Pinworms

Is this your child’s symptom?

• Tiny, harmless worms that can cause anal itching
• The pinworms live in the colon (large bowel)

Symptoms of Pinworms

• Itching and irritation of the anus and buttocks is the main symptom
• Sometimes, moves to the vagina and causes vaginal itching or discharge

Cause

• A white, very thin, threadlike worm, about ¼ inch (6 mm) long.
• It moves. If it doesn’t wiggle, it’s probably lint or a thread.
• The worm may be seen around the anus or on the child’s bottom. It is especially active at night or early morning.
• Rarely, the pinworm is seen on the surface of a stool.
• The pinworm’s secretions are a strong skin irritant and cause the itching.

When to Call for Pinworms

Contact Doctor During Office Hours

• Pinworm is seen. Reason: needs a pinworm medicine.
• Red and tender skin around the anus. Reason: could be Strep infection.
• Anal itching lasts more than 1 week
• You think your child needs to be seen
• You have other questions or concerns

Self Care at Home

• Anal itching without a pinworm being seen
• Questions about pinworm exposure or contact

Seattle Children’s Urgent Care Locations

If your child’s illness or injury is life-threatening, call 911.

Care Advice

Treatment for Pinworms

1. What You Should Know About Pinworm Treatment:
   • Pinworms are the most common worm infection in the US.
   • Pinworms can cause anal itching.
   • Pinworms do not carry any diseases.
   • Treatment is very helpful.
   • Here is some care advice that should help.
2. Pinworm Medicine:
   • If a pinworm was seen, your child’s doctor will suggest a special pinworm medicine. Pinworm medicines are available without a prescription (such as Reese’s Pinworm Medicine). There are also prescription medicines that treat pinworms. Your doctor will decide which one is best for your child. Take as directed.
   • Give a repeat dose of the pinworm medicine in 2 weeks. Reason: To prevent the pinworms from coming back.
   • The repeat dose is needed because eggs can live for 1 to 2 weeks. Temperature and humidity levels also affect how long the eggs can stay alive.
3. Treating Close Contacts:
   • There is a slight risk that Pinworms may spread to others.
   • Treat family members only if they have symptoms.
   • If another child sleeps with the infected child, they also should be treated.
   • If any of your child’s friends have symptoms, be sure to tell their parents. These children should get tested or checked for pinworms.
4. Return to School:
   • Children with pinworms do not need to miss any child care or school.
5. What to Expect:
   • After taking the pinworm medicine, itching should stop in 5 to 7 days.
6. Prevention of Pinworms:
   • Wash hands and fingernails well before meals and after using the toilet.
7. Call Your Doctor If:
   • Anal symptoms last over 1 week after treatment
   • You think your child needs to be seen
   • Your child becomes worse

Treatment for Anal Itching Without Pinworm Being Seen

1. What You Should Know About Anal Itching:
   • There are many causes of itching around the anus. Some are more common than pinworms.
   • The most common cause is stool that has been left on the skin. Stool contains chemicals and germs that can cause itchy skin rashes. Try to prevent this by washing the skin off. After wiping off stool with toilet tissue, cleanse the skin with warm water.
   • Bubble bath can also cause an itchy bottom. Children with dry skin are at increased risk. Avoid bubble bath or any soapy bath water.
   • If these changes don’t get rid of the anal itching, get a pinworm test.
2. Pinworm Checks: Check your child for pinworms.
   • Examine the area around the anus, using a flashlight.
   • Look for a ¼-inch (6 mm), white, threadlike worm that moves.
   • Do this a few hours after your child goes to bed. Check him 2 nights in a row. Also, check him first thing in the morning for 2 days.
3. Scotch Tape Test:
   • If no adult pinworm is seen, call your doctor’s office. Ask for instructions on doing a Scotch-tape test for pinworm eggs. You can also use the technique below:
   • Take a piece of clear Scotch tape with the sticky side down. Touch it to the skin on both sides of the anus. Do this in the morning soon after your child has awakened. Also, do this before any bath or shower.
   • Put the sticky tape side that touched the skin on a slide. If you don’t have a slide, put it on a second piece of tape.
   • Do it 2 mornings in a row.
   • Bring the 2 samples in to be looked at under a microscope.
4. Steroid Cream for Itching:
   • For the itching, wash the skin around the anus with warm water.
   • For severe itch, use 1% hydrocortisone cream (such as Cortaid) 2 times per day. Use for 1 or 2 days. No prescription is needed.
5. Call Your Doctor If:
   • Pinworm is seen
   • Skin around the anus gets red or tender
   • Anal itching lasts more than 1 week
   • You think your child needs to be seen
   • Your child becomes worse

Treatment for Pinworm Exposure

1. Low Risk for Getting Pinworms:
   • Your child has had contact with a child with pinworms, but no symptoms now. Your child probably won’t get them. This is especially likely if over a month has passed.
   • If contact is within the last month, your child may get pinworms. This risk is small.
   • Pinworms are harmless. They are never present very long without being seen or causing anal itching.
2. Scotch Tape Test:
   • If you’re still worried, call your doctor’s office. Ask for instructions on doing a Scotch tape test. This can be done to look for pinworm eggs.
   • Do this about 1 month after contact.
   • Reason: The swallowed egg will not become an adult pinworm for 3 or 4 weeks.
3. Call Your Doctor If:
   • Pinworm is seen (white, ¼ inch or 6 mm, and moves)
   • Anal itching lasts more than 1 week
   • You think your child needs to be seen

Treatment for Reducing Reinfection or Spread to Others

1. Preventing Pinworm Infections:
   • Infection is caused by swallowing pinworm eggs.
   • A child can get pinworms no matter how carefully you clean.
   • The following hygiene measures, however, can help to reduce the chances of reinfection. It also can reduce the chance of new infections in other people.
   • Pets don’t carry pinworms.
2. Wash Hands:
   • Have your child scrub the hands and fingernails well before each meal. Also, wash the hands well after each use of the toilet.
   • Keep the fingernails cut short, because eggs can collect here.
   • Help your child give up thumb sucking and nail biting.
3. Shower:
   • Each morning give your child a shower.
   • Always rinse the anal area.
   • Do this for 3 days after taking the pinworm medicine.
4. Vacuum:
   • Vacuum or wet-mop your child’s bedroom once a week.
   • Any eggs left on the floor can still infect others for 1 or 2 weeks.
5. Wash Clothes:
   • Wash clothes and bedding at a hot temperature. This will kill any eggs left in them.
6. Return to School:
   • Children with pinworms do not need to miss any child care or school.

And remember, contact your doctor if your child develops any of the ‘Call Your Doctor’ symptoms.

Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.

Last Reviewed: 09/16/2021

Last Revised: 03/11/2021

Copyright 2000-2021. Schmitt Pediatric Guidelines LLC.

Pinworm Infestation Mimicking Crohns’ Disease

We here report a case of a young man who presented to his general practitioner with diarrhea. Inflammatory bowel disease was suspected and a colonoscopy showed aphthous lesions suggestive of Crohns’ disease but biopsies revealed eggs of Enterobius vermicularis. When treated for this parasite, his symptoms were alleviated and a followup colonoscopy revealed a normal colon and distal ileum. Enterobius vermicularis is the most common parasite worldwide and has been attributed with many different presentations and pathologies. It is therefore necessary to maintain vigilance, even in high-income countries, in order to diagnose patients with one of the many atypical presentations of pinworms.

1. Introduction

In Scandinavia, the presence of aphthous ulcerations and erosions in the distal ileum and caecum is usually a manifestation of Crohns disease. However numerous differential diagnoses exist and histopathological confirmation is required in order not to give the patient the lifelong diagnosis of Crohns disease inaccurately.

Enterobius vermicularis is the most common helmintic parasite known, affecting all members of society regardless of age, gender, and social status [1]. They typically reside in the caecum, appendix and distal ileum, where they adhere to the mucosa [2]. Although many infections are asymptomatic, perianal itching, especially at night, is the most common symptom [1]. However there are a lot of atypical presentations described in the literature, for example, infections of the kidneys [3] and infections of the female genital tract [4] as well as many other presentations.

Typically the diagnosis rests upon applying cellophane or scotch tape to the perianal skin in the morning, removing it, and detecting eggs using the microscope [1, 5]. The worms can however be seen during endoscopy [6], and both the worm and its eggs can be found in histological specimens [5, 7]. Once diagnosed the infection is eradicated with two doses of Mebendzole two weeks apart as well as hygienic measures [8].

We here present a case of a young man with an Enterobius vermicularis infection which mimics Crohns disease.

2. Case Presentation

A 22-year-old man presented to his GP with an exacerbation of diarrhea during the past two months. He reported that he usually had diarrhea once or twice a week mostly on weekends and on daytime normally beginning as abdominal cramps that was relieved by defecation. During the past two months, he had been having an increased amount of watery-thin diarrhea 5-6 days a week. He now had symptoms also during the night and with no relation to food intake. In addition abdominal cramps were sustained during the days of diarrhea. He had not been outside Sweden recently. Blood work included liver function tests, creatinine, ions, anti- transglutaminase and gliadin antibodies, thyroid function tests, a full blood count, stool culture and microscopy for cysts and worms. They all came back negative. He was diagnosed with IBS and his GP prescribed inolaxol and loperamide.

He returned six months later with a history of one week of watery-thin diarrheas without mucus or blood. He also had abdominal cramps, nausea, and a fever of 38°C but no cardiopulmonary or mictuition problems. This time ESR was elevated as well as CRP and a blood count showed leucocytosis. He had not been traveling outside Sweden nor received antibiotics recently. Infectious enterocolitis was suspected and a stool culture was obtained.

Four days later the stool culture came back negative, his symptoms were slightly better, and CRP had dropped significantly. His GP suspected noninfectious bowel disease and ordered a quick test for fecal calprotectin. When it showed >60 μg/g of feces he was referred for a colonoscopy.

The colonoscopy showed a normal colon up till mid transverse colon where erosions started to appear. These erosions increased distally up until the caecum (Figure 1), where aphthous ulcerations upon a erythematic base was seen. In the distal ileum cobblestone pattern was seen together with multiple erosions (Figure 2). The morphology suggested Crohns disease and multiple biopsies were taken and an MRI of the small bowel was scheduled; the patient was given Prednisolone which alleviated his symptoms.

When the biopsy results came back four weeks later they showed no crypt abscesses and no granulomas. In ileum lymphoid hyperplasia with germinal centers was found as well as focal neutrophilic infiltrates (Figures 3 and 4). In caecum and ascending colon a few spots with cryptitis were found. The most remarkable finding was a female larvae of Enterobius vermicularis with numerous eggs lying in the intestinal lumen (Figure 5). The patient was therefore given a single dose of Mebendazole with a second dose two weeks later. Three days after the first dose he still had an elevated fecal calprotectin and although he no longer had diarrhea he experienced nausea and vomiting. The MRI was normal and prednisolone was scaled out.

A follow-up colonoscopy five months later revealed a macroscopically normal colon and distal ileum; biopsies were taken and they revealed lymphoid hyperplasia in the distal ileum and a normal caecum and colon. Fecal calprotectin was normalized during the following months and he remains symptom free.

3. Discussion

To our knowledge only three other cases of Enterobius vermicularis mimicking Crohns disease have been reported in the literature [2, 9, 10]. It is believed that Enterobius vermicularis cannot penetrate the intestinal mucosa unless there is some insult to the mucosal barrier. They are however known to be associated with colonic ulcerations but the question of causation remains unanswered. Using the Rome III criteria it is probable that our patient has IBS, but since IBS is not associated structural derangement of the colonic mucosa we have no indication of a previous insult to the mucosa. In two of the previous cases presented by Beattie et al. [9] and McDonald and Hourihane [2] a reasonable mechanism of mucosal damage was present. In the case presented by McDonald and Hourihane [2] a perforated appendix was deemed reason behind the symptomatic Enterobius vermicularis. Also in the case presented by Beattie et al. [9] Campylobacter jejuni was found in a stool culture and may have contributed to mucosal damage. The third case by Fernandez-Flores and Dajil [10] contains no explaining factor, as in the present case. The previous authors have described that the worms attach themselves to the mucosa using their heads [2]. This may cause the ulceration necessary for the pinworms to become invasive but the question remains unanswered.

As in the case presented by Beattie et al. we could demonstrate a normal colon and distal ileum during a follow-up colonoscopy. In our case we could also show a normalized fecal calprotectin indicating that the mucosal inflammation had ceased. The prompt response of his symptoms to Prednisolone is probably due to the anti-inflammatory effect of the drug, limiting the mucosal inflammation, which gave him his symptoms. Despite prednisolone however his fecal calprotectin was elevated and did not start to drop until he received Mebendazole. This also highlights the importance of a correct diagnosis since Crohns disease is a chronic disease there is a possibility that future flare-ups could have been treated as Crohns disease. The diagnosis of Crohns disease must therefore rest upon stronger evidence than slight macroscopic changes and therapeutic evaluation since it could mask other causes such as an Enterobius vermicularis infection.

The question whether the worm we found in the lumen could have caused this inflammatory reaction does not have a definitive answer. In the case reported by McDonald and Hourihane worms were indeed present in the intestinal wall. However in the cases presented by Fernandez-Flores and Dajil the worm was found solely in the lumen covered by eosinophils. The worm was described as being found at the base of an ulcer in the case presented by Beattie et al. but the worm was deemed invasive by the authors. Lastly in a case where Enterobius vermicularis caused eosinophilic ileocolitis no worms were found in biopsy specimens obtained during colonoscopy instead the worm was found during stool examination [11].

In conclusion, the histopathological finding of a pinworm and the lasting remission after Mebendazole treatment lean towards the notion that Enterobius vermicularis infection and not Crohns disease is the cause of his symptoms. Since the patient responded well to Mebendazole and the inflammatory infiltrates found in the biopsy specimen were not typical for Crohns disease, we believe that our patients symptoms were caused by Enterobius vermicularis. It is today unknown if Enterobius vermicularis is an invasive pathogen or if structural damage is required for invasive infection. Enterobius vermicularis might be an important differential diagnosis to Crohns disease even in Scandinavia and other highly industrialized nations, since this easily treated parasite infection can greatly reduce the patients quality of life. It is necessary to maintain vigilance among pathologists since an Enterobius vermicularis infection can be very similar to Crohns disease during colonoscopy.

Acknowledgment

The authors would like to thank Magnus Ström for his careful and critical reading of our paper.

Copyright

Copyright © 2013 Joel Johansson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Rectal Bleeding

Is this your symptom?

• Blood mixed in with the stool or passed separately
• Bloody or maroon-colored stools
• Tarry-black stools
• Blood just on toilet paper or a few drops into toilet water
• Streaks on surface of normal formed bowel movement (stool)

Some Basics.

..

• Rectal bleeding is never normal. However, it is not always serious.
• Sometimes bleeding can be mild. There may be just a few drops of blood in the stool or blood on the toilet paper. Often this is from hemorrhoids (piles) or a small scratch from a hard stool.
• Sometimes bleeding can more severe. There may be blood clots, bloody stool or black stool. There can be a number of possible causes. A visit to the doctor is needed.

Causes

Some common causes of rectal bleeding are:

• Anal fissure: This is a small crack or tear in the skin of the anus. It may result from passing hard stools or from having many diarrhea stools. Symptoms are pain during and right after passing a stool, mild rectal bleeding, and rectal itching.
• Hemorrhoids: Another name for these is piles. These are enlarged veins that are just inside (“internal”) or outside (“external”) the rectal opening (anus). Two top reasons why people get hemorrhoids are constipation and pregnancy. People with bleeding hemorrhoids often see blood in the toilet water or small amounts of blood on the stool.

Some less common causes of rectal bleeding are:

• Angiodysplasia
• Cancer of colon (intestines)
• Cancer of rectum (anus)
• Colon polyps
• Crohn’s Disease
• Diarrhea
• Proctitis
• Pseudomembranous colitis
• Radiation treatment
• Rectal foreign object
• Ulcerative colitis

Types of Rectal Bleeding

• Bright red blood just on toilet paper: This is least serious. It often means that the bleeding is coming from the rectal opening (anus). The two most common causes of this type of bleeding are hemorrhoids and anal fissures.
• Bright red blood on the surface of a stool: This often means that the bleeding is from the anus or just inside. This can be caused by hemorrhoids or anal fissures. It can also be caused by more serious problems like cancer and polyps.
• Blood mixed with a stool: This usually means that there is a disease or problem inside the rectum or higher up in the colon (intestines). Examples are colon cancer, colon polyps, diverticulosis, and ulcerative colitis.
• Blood mixed with diarrhea: This may be a sign of a more severe colon infection. Other causes of bloody diarrhea are Crohn’s disease and ulcerative colitis.
• Tarry-black stool: This may be a sign of more severe bleeding from the stomach or esophagus. When the blood passes through the gut and comes out the rectum, it can make the stool look black or tarry. Stomach acid breaks down the blood and turns it black.

Severity of Rectal Bleeding is defined as:

• Drops, Spots, Streaks: blood on toilet paper or a few drops in toilet bowl; streaks or drops of blood on surface of stool
• Mild: more than just a few drops or streaks
• Moderate: small blood clots, passing blood without stool, or toilet water turns red
• Severe: large blood clots; on and off, or constant bleeding

What can Cause Red or Black Stools… that is Not Blood?

Causes of black-colored stools (not blood) are:

• Bismuth (Pepto-Bismol)
• Black licorice
• Blueberries
• Dark green stools may sometimes look like black. Put stool on white paper and hold under bright light. Is it green or black? Spinach and other dark vegetables can make stool look dark green.

Causes of red-colored stools (not blood) are:

• Beets
• Cranberries
• Medicines (Omnicef)
• Red food coloring dyes (red gelatin/Jell-O, red Kool-Aid)
• Red licorice
• Tomato juice or soup

When to Call for Rectal Bleeding

Care Advice

Mild Rectal Bleeding

1. What You Should Know:
   • Rectal bleeding is never normal. However, it is not always serious.
   • Sometimes bleeding can be very mild. There may be just a few drops of blood in the stool or blood on the toilet paper. Often this is from hemorrhoids (piles) or a small scratch from a hard stool.
   • You can treat very mild rectal bleeding from hemorrhoids, anal fissure, or constipation at home.
   • Here is some care advice that should help.
2. Warm SITZ Baths Twice a Day:
   • Sit in warm bath water for 20 minutes 2 times each day. This helps clean and heal the rectal area.
   • If you want, you can add ¼ cup (80 grams) of table salt or baking soda to each tub of water. Stir the water until it dissolves.
   • This is also called a Sitz bath.
3. Stool Softener for Hard Bowel Movements:
   • If you have hard stools, stool softeners can help soften the stool. This can help decrease rectal pain when passing stool.
   • Docusate (Colace) is a stool softener that you can get over-the-counter.
4. Call Back If:
   • Bleeding increases
   • Bleeding lasts more than 3 days
   • Bleeding is off and on for weeks or months
   • You think you need to be seen
   • You get worse

Constipation

1. What You Should Know:
   • Trouble passing a stool, hard stools, and infrequent stools are signs of constipation.
   • Healthy living habits can help treat and prevent constipation. Healthy habits include eating a diet high in fiber and regular exercise.
   • You can treat mild constipation at home.
   • Here is some care advice that should help.
2. Eat a High Fiber Diet:
   • Slowly increase the amount of fiber in your diet. This will help soften your stools. Fiber works by holding more water in your stools.
   • Eat more fresh fruit and vegetables. They are great sources of natural fiber. This includes peas, prunes, citrus, apples, beans, and corn.
   • Eat more foods made from whole grains. Foods made from whole grains also have fiber. Examples are bran flakes, bran muffins, graham crackers, oatmeal, brown rice, and whole wheat bread. Popcorn is also a good source of fiber.
3. Liquids:
   • Drinking enough liquids is important to keep your stools soft.
   • Drink 6-8 glasses of water a day. Caution: certain medical problems require fluid restriction.
   • Prune juice is a natural laxative.
   • Avoid alcohol.
4. Exercise:
   • Staying active is always a healthy choice.
   • Regular exercise decreases constipation.
   • Even a daily walk for 15 minutes helps.
5. Call Your Doctor If:
   • Constipation lasts more than 2 weeks after using Care Advice
   • Stomach swelling, vomiting or fever occur
   • Constant or increasing stomach pain
   • You think you need to be seen
   • You get worse

Over-the-Counter (OTC) Medicines for Constipation

1. Step-By-Step: A step-by-step approach to using OTC medicines for constipation is best.

2. Step 1 – Use a Fiber Laxative Every Day:
   • You can take a fiber laxative every day instead of eating more fiber.
   • An example of a fiber laxative is psyllium (Metamucil). You can buy this at the store without a prescription.
   • Fiber can help soften your stools. Fiber works by holding more water in your stools. Be patient. Sometimes this takes 1 to 2 weeks to work.
   • Osmotic Laxatives, as needed: You can take milk of magnesia or polyethylene glycol (PEG, Miralax). This type of medicine helps pull water into your intestines. This softens the stools.
   • Read the instructions and warnings on the package insert for all medicines you take.
3. Step 2 – Add a Stool Softener:
   • For stools that are more firm or hard, try an over-the-counter stool softener. An example is docusate (Colace, Surfak).
   • These medicines soften stools and make them easier to pass. You can buy them at the store.
   • They may take 1 to 2 days to start working.
   • Read the instructions and warnings on the package insert for all medicines you take.
4. Step 3 – Use an Osmotic Laxative if Needed:
   • If needed, you can try an osmotic laxative to treat occasional constipation. Examples are polyethylene glycol (PEG and Miralax) and milk of magnesia. You can buy these at the store without a prescription. Another option is to try a glycerine rectal suppository.
   • These medicines help pull water into your intestines. This softens the stools. They often start working in 1 to 2 days. Glycerine suppositories often work within an hour or less.
   • Do not use laxatives for more than 2 weeks unless your doctor instructs you to do this.
   • Caution: do not use milk of magnesia if you have kidney disease.
   • Caution: if you are pregnant, talk to your doctor before using these laxatives.
   • Read the instructions and warnings on the package insert for all medicines you take.
5. Step 4 – Add a Stimulant Laxative:
   • If the constipation does not get better with the Care Advice in the above 3 steps, add a stimulant laxative. Use only if needed.
   • Try bisacodyl (Dulcolax) tablets. You can buy these at the store without a prescription.
   • These laxatives often work in 6 to 12 hours. Another option is Senna. This is a mild, plant-based laxative.
   • Do not use laxatives for more than 2 weeks unless your doctor instructs you to do this.
   • Caution: do not use stimulant laxatives if you are pregnant.
   • Read the instructions and warnings on the package insert for all medicines you take.
6. Call Your Doctor If:
   • Constipation lasts more than 2 weeks after using Care Advice
   • Stomach swelling, vomiting or fever occur
   • Constant or increasing stomach pain
   • You think you need to be seen
   • You get worse

And remember, contact your doctor if you develop any of the ‘Call Your Doctor’ symptoms.

Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.

Parasitic Infection, Pinworm Symptoms, Treatment

Overview

What are roundworms?

Roundworms are small organisms that can live in your intestines, part of your digestive system for a long time. They can be harmful and cause many problems, including abdominal (belly) pain, fever and diarrhea.

Roundworms have long, round bodies and can be different sizes, depending on the type. The eggs or larvae (newly hatched roundworms) often live in infected soil or stool (poop).

What is a parasite?

Roundworms are parasites — organisms that need to live on or in another creature (the host) to survive. Often, the parasite causes problems for its host. For roundworms, they need the body of a human or another animal to mature into egg-laying adults.

How common are roundworms?

Hundreds of millions of people around the world are infected with roundworms at any given time. But many of these parasites are uncommon in the United States. Americans may come into contact with them when traveling to certain countries.

Pinworms are the most common roundworm infection in the United States, affecting 20 to 42 million people, many of them children.

How does a person get infected with roundworms?

The route into the body depends on the type of roundworm. Many of these parasites enter the body through the mouth. Infection often happens from touching poop or soil that is infected with eggs and not washing hands (fecal-oral route). Pinworm infections result from touching eggs laid near the opening of the buttocks (anus).

People can accidentally ingest roundworm eggs by preparing food or touching soil that is contaminated. The eggs then hatch inside the body.

For other roundworms, eggs may hide in the food people eat. And in some cases, larvae can enter the body directly through the skin. Regardless of how they enter, most roundworms end up in the intestines, causing infection or disease.

Who is at risk for roundworms?

Anyone can get roundworms. Roundworm infections are more common in children and people who are:

• Living in poverty, especially in underdeveloped areas of the world.
• Living in warm climates.
• Living in an institution, such as a prison or mental health facility.
• Not practicing good hygiene.

Are roundworms contagious?

Yes. If you come into contact with infected poop of people or animals, you can get roundworms. You can also get them by touching infected surfaces, like soil.

Can I get roundworms from my pets?

Yes. If your pet has roundworms, you can be exposed to the eggs or larvae in their poop. A pet with roundworms can spread the disease to many people. Talk to your veterinarian about protecting you and your pet from roundworms.

Symptoms and Causes

What causes roundworms?

Each type of roundworm has different causes as well as different symptoms.

What are the causes and symptoms of roundworm infection of your intestines (ascariasis)?

This type of roundworm spreads through poor hygiene. It often lives in human feces (poop). People catch it through hand-to-mouth contact.

If you have a roundworm infection of your intestines (ascariasis), you may not have symptoms. You may see live worms in your poop though. If you do have symptoms, they may include:

What are the causes and symptoms of hookworm?

People get hookworm by walking barefoot on dirt mixed with infected poop.

If you have hookworm, you may not notice symptoms if your health is otherwise good. If you do have symptoms, the signs may include:

• Anemia, when you don’t have enough red blood cells, making you feel tired and weak.
• Colic, a lot of crying and fussiness in an otherwise healthy baby.
• Diarrhea.
• Mild abdominal pain and intestinal cramps.
• Nausea.

What are the causes and symptoms of pinworm?

Pinworm is the most common roundworm infection in the United States. It occurs most often in children and can spread easily in school or day care. The infection starts when eggs enter the mouth and travel to the intestines. The eggs hatch and develop into adult pinworms.

A female pinworm then lays her eggs in and around the anus (opening of the buttocks). Without realizing it, people touch the eggs with their fingers. For example, a small child might touch or scratch their bottom or not wash their hands after using the bathroom. Parents may not wash their hands properly after changing a diaper of a child who has pinworms.

After touching an infected area, people may put their fingers in or near their mouths or touch surfaces. Pinworm eggs can attach to bedding, clothing, toys, doorknobs, furniture and faucets for up to two weeks.

Those with pinworm infections may experience mild symptoms or none at all. The most common symptom is itching around the anus or vagina. The itching can become intense after a pinworm lays eggs.

What are the causes and symptoms of strongyloidiasis?

This type of roundworm mainly lives in tropical and subtropical areas, where it’s warm year-round. But it can also live in other regions during warmer seasons. People get infected by touching contaminated soil. Strongyloidiasis enters through the skin and travels to the intestines.

Some people may experience mild symptoms or none at all. If you have a moderate infection, you may feel:

Severe strongyloidiasis infections may cause:

• Anemia.
• Chronic (long-lasting) diarrhea.
• Weight loss.

What are the causes and symptoms of trichinellosis?

Trichinellosis is different than other roundworm infections. It’s not an intestinal infection. It affects your muscles. You get it through eating undercooked meat, especially sausage, pork, horse, walrus and bear meat.

Some people may experience mild symptoms or none at all. But you may feel tired or get stomach symptoms, including:

• Diarrhea.
• Stomach cramps.

When trichinosis enters the muscles, you may get:

• Eye infection and rashes.
• High fever.
• Muscle pain and aches.
• Swelling in the eyes and face.

What are the causes and symptoms of whipworm?

You get whipworm by:

• Touching it with your hands.
• Eating food that has whipworms on it.
• Eating food that was grown in soil with whipworms.

There are usually no symptoms with whipworm. However, if you have a severe infection, you may experience:

• Blood in your poop.
• Diarrhea.
• Stomach pains that come and go.
• Weight loss.
• Anemia.

Diagnosis and Tests

Should I call my healthcare provider if I may have roundworms?

Yes. It’s important to get a proper diagnosis for roundworms. Tell your provider if you have:

• Come into contact with wild animals or infected pets.
• Eaten raw or undercooked meats.
• Seen a worm or part of a worm in your poop.
• Traveled to an area with poor hygiene and sanitation in the last two years.

How are roundworms diagnosed?

Your healthcare provider will ask you about your medical history and symptoms. Then you will probably need a blood test. Your provider may also ask for a stool sample to test it for eggs. To get a stool sample, your provider gives you a sterile (germ-free) container. You place a poop sample in the container and bring it to your provider or a lab.

Management and Treatment

How are roundworms treated?

While there are various kinds of roundworms, they usually all have the same treatment. Your provider will prescribe a medicine called albendazole. This medicine prevents the larvae from getting bigger or multiplying. The worms in your body then pass through your poop. You may not even notice it happening.

Depending on the type of roundworm, you may need to repeat the treatment after a few weeks. Doing so makes sure the parasites are completely gone.

You may also need a prescription for an iron supplement to help with anemia. And a prescription cream can help stop any itching.

Prevention

Can I prevent roundworms?

Take steps to prevent roundworm infections:

Pet safety:

• Clean up dog or animal poop in your yard.
• Get your pet dewormed. Talk to your vet about a deworming schedule that’s right for your pet.

Good hygiene:

• Make sure children don’t play near an animal’s poop.
• Teach children not to eat dirt or soil.
• Wash hands well with soap and hot water, especially after playing with pets or doing outdoor activities.

Food and drink safety:

• Don’t eat raw fruits and vegetables in areas with poor sanitation.
• Don’t eat raw or undercooked meats, including meat from wild animals and pork, poultry, beef or fish.
• If you’re traveling to an area without modern sanitation, only drink bottled water.
• Wash garden-grown fruits and vegetables well.

Outlook / Prognosis

How long does roundworm treatment take to work?

The medicine destroys roundworms in about three days.

What’s the outlook for people with roundworm infection?

Most roundworm infections don’t cause long-term problems. Follow your provider’s instructions for taking your medicine. Take precautions to prevent an infection from happening again.

Living With

How should I take care of myself?

Take your medicine as prescribed. Wash bedding and towels in hot water. If you’re planning to travel to a high-risk area, talk to your provider about preventive medications.

When should I call my healthcare provider?

Contact your provider if you:

• Have a red, itchy rash on your skin.
• Have stomach problems that last longer than two weeks — such as diarrhea or a stomachache.
• Have unexplained weight loss.
• See a worm or piece of a worm in your poop.

What else should I ask my healthcare provider?

If you have a roundworm infection, ask your provider:

• Will I need medication?
• How long should I take medication?
• Will the infection come back?
• Will there be long-term health problems from the roundworm infection?
• What can I do to protect myself from roundworms?

A Note from Cleveland Clinic

Roundworms are a group of parasites that includes pinworms and ascariasis. These tiny organisms enter your body, where they often live in your digestive system and cause problems. You can get roundworms by coming into contact with roundworm eggs or larvae. See your healthcare provider if you have symptoms of pinworm or other roundworms. A round of medication usually treats the infection. People don’t usually have long-term health effects from roundworms.

Common Intestinal Parasites – American Family Physician

CORRY JEB KUCIK, LT, MC, USN, GARY L. MARTIN, LCDR, MC, USN, and BRETT V. SORTOR, LCDR, MC, USN, Naval Hospital Jacksonville, Jacksonville, Florida

Am Fam Physician. 2004 Mar 1;69(5):1161-1169.

Intestinal parasites cause significant morbidity and mortality. Diseases caused by Enterobius vermicularis, Giardia lamblia, Ancylostoma duodenale, Necator americanus, and Entamoeba histolytica occur in the United States. E. vermicularis, or pinworm, causes irritation and sleep disturbances. Diagnosis can be made using the “cellophane tape test.” Treatment includes mebendazole and household sanitation. Giardia causes nausea, vomiting, malabsorption, diarrhea, and weight loss. Stool ova and parasite studies are diagnostic. Treatment includes metronidazole. Sewage treatment, proper handwashing, and consumption of bottled water can be preventive. A. duodenale and N. americanus are hookworms that cause blood loss, anemia, pica, and wasting. Finding eggs in the feces is diagnostic. Treatments include albendazole, mebendazole, pyrantel pamoate, iron supplementation, and blood transfusion. Preventive measures include wearing shoes and treating sewage. E. histolytica can cause intestinal ulcerations, bloody diarrhea, weight loss, fever, gastrointestinal obstruction, and peritonitis. Amebas can cause abscesses in the liver that may rupture into the pleural space, peritoneum, or pericardium. Stool and serologic assays, biopsy, barium studies, and liver imaging have diagnostic merit. Therapy includes luminal and tissue amebicides to attack both life-cycle stages. Metronidazole, chloroquine, and aspiration are treatments for liver abscess. Careful sanitation and use of peeled foods and bottled water are preventive.

Intestinal parasites cause significant morbidity and mortality throughout the world, particularly in undeveloped countries and in persons with comorbidities. Intestinal parasites that remain prevalent in the United States include Enterobius vermicularis, Giardia lamblia, Ancylostoma duodenale, Necator americanus, and Entamoeba histolytica.

E. vermicularis

E. vermicularis, commonly referred to as the pinworm or seatworm, is a nematode, or roundworm, with the largest geographic range of any helminth.1 It is the most prevalent nematode in the United States. Humans are the only known host, and about 209 million persons worldwide are infected. More than 30 percent of children worldwide are infected.2

Adult worms are quite small; the males measure 2 to 5 mm, and the females measure 8 to 13 mm. The worms live primarily in the cecum of the large intestine, from which the gravid female migrates at night to lay up to 15,000 eggs on the perineum. The eggs can be spread by the fecal-oral route to the original host and new hosts. Eggs on the host’s perineum can spread to other persons in the house, possibly resulting in an entire family becoming infected.

Ingested eggs hatch in the duodenum, and larvae mature during their migration to the large intestine. Fortunately, most eggs desiccate within 72 hours. In the absence of host autoinfection, infestation usually lasts only four to six weeks.

Disease secondary to E. vermicularis is relatively innocuous, with egg deposition causing perineal, perianal, and vaginal irritation.3 The patient’s constant itching in an attempt to relieve irritation can lead to potentially debilitating sleep disturbance. Rarely, more serious disease can result, including weight loss, urinary tract infection, and appendicitis.4,5

Pinworm infection should be suspected in children who exhibit perianal pruritus and nocturnal restlessness. Direct visualization of the adult worm or microscopic detection of eggs confirms the diagnosis, but only 5 percent of infected persons have eggs in their stool. The “cellophane tape test” (Figure 1) can serve as a quick way to clinch the diagnosis.6,7

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FIGURE 1.

“Cellophane tape test.” (Top) Affix the end of the tape near one end of the slide. Loop the rest of the tape over the end of the slide so the adhesive surface is exposed. (Center) Touch the adhesive surface to the perianal region several times. (Bottom) Smooth down the tape across the surface of the slide.

FIGURE 1.

“Cellophane tape test.” (Top) Affix the end of the tape near one end of the slide. Loop the rest of the tape over the end of the slide so the adhesive surface is exposed. (Center) Touch the adhesive surface to the perianal region several times. (Bottom) Smooth down the tape across the surface of the slide.

This test consists of touching tape to the perianal area several times, removing it, and examining the tape under direct microscopy for eggs. The test should be conducted right after awakening on at least three consecutive days. This technique can increase the test’s sensitivity to roughly 90 percent.

FIGURE 2

Giardia lamblia cyst.

Reprinted from Centers for Disease Control and Prevention. Accessed November 15, 2003, athttp://phil.cdc.gov.

G. lamblia

G. lamblia is a pear-shaped, flagellated protozoan (Figure 2) that causes a wide variety of gastrointestinal complaints. Giardia is arguably the most common parasite infection of humans worldwide, and the second most common in the United States after pin-worm.8,9 Between 1992 and 1997, the Centers for Disease Control and Prevention (CDC) estimated that more than 2.5 million cases of giardiasis occur annually.10

Because giardiasis is spread by fecal-oral contamination, the prevalence is higher in populations with poor sanitation, close contact, and oral-anal sexual practices. The disease is commonly water-borne because Giardia is resistant to the chlorine levels in normal tap water and survives well in cold mountain streams. Because giardiasis frequently infects persons who spend a lot of time camping, backpacking, or hunting, it has gained the nicknames of “backpacker’s diarrhea” and “beaver fever.”11

Food-borne transmission is rare but can occur with ingestion of raw or undercooked foods. Giardiasis is a zoonosis, and cross-infectivity among beaver, cattle, dogs, rodents, and bighorn sheep ensures a constant reservoir.12

The life cycle of Giardia consists of two stages: the fecal-orally transmitted cyst and the disease-causing trophozoite. Cysts are passed in a host’s feces, remaining viable in a moist environment for months. Ingestion of at least 10 to 25 cysts can cause infection in humans.8,9 When a new host consumes a cyst, the host’s acidic stomach environment stimulates excystation. Each cyst produces two trophozoites. These trophozoites migrate to the duodenum and proximal jejunum, where they attach to the mucosal wall by means of a ventral adhesive disk and replicate by binary fission.

Giardia growth in the small intestine is stimulated by bile, carbohydrates, and low oxygen tension.7 It can cause dyspepsia, mal-absorption, and diarrhea. A recent theory suggests that the symptoms are the result of a brush border enzyme deficiency rather than invasion of the intestinal wall.9 Some trophozoites transform to cysts and pass in the feces.

Clinical presentations of giardiasis vary greatly. After an incubation period of one to two weeks, symptoms of gastrointestinal distress may develop, including nausea, vomiting, malaise, flatulence, cramping, diarrhea, steatorrhea, and weight loss. A history of gradual onset of a mild diarrhea helps differentiate giardiasis or other parasite infections from bacterial etiologies. Symptoms lasting two to four weeks and significant weight loss are key findings that indicate giardiasis.

Chronic giardiasis may follow an acute syndrome or present without severe antecedent symptoms. Chronic signs and symptoms such as loose stool, steatorrhea, a 10 to 20 percent loss in weight, malabsorption, malaise, fatigue, and depression may wax and wane over many months if the condition is not treated.

Rarely, patients with giardiasis also present with reactive arthritis or asymmetric synovitis, usually of the lower extremities.13 Rashes and urticaria may be present as part of a hypersensitivity reaction.

Cyst excretion occurs intermittently in both formed and loose stools, while trophozoites are almost only found in diarrhea. Stool studies for ova and parasites (O&P) continue to be a mainstay of diagnosis despite only low to moderate sensitivity. Examination of a single stool specimen has a sensitivity of 50 to 70 percent; the sensitivity increases to 85 to 90 percent with three serial specimens.8,10 Because Giardia is not invasive, eosinophilia, and peripheral or fecal leukocytosis do not occur.

Antigen assays use enzyme-linked immunosorbent assay (ELISA) or immunofluo-rescence to detect antibodies to trophozoites or cysts. Sensitivities range from 90 to 99 percent, with specificities of 95 to 100 percent compared with stool O&P.9 Despite the high yield of these studies, direct microscopy is still important, because multiple diarrhea-causing infectious etiologies can be present simultaneously.

Duodenal aspirates and biopsies give a higher yield than stool studies but are invasive and usually not necessary for diagnosis. Serology and stool cultures are generally unnecessary. Polymerase chain reaction (PCR) analysis, while only experimental, may be effective for screening water supplies.9

A. duodenale and N. americanus

Two species of hookworm, A. duodenale and N. americanus, are found exclusively in humans. A. duodenale, or “Old World” hookworm, is found in Europe, Africa, China, Japan, India, and the Pacific islands. N. americanus, the “New World” hookworm, is found in the Americas and the Caribbean, and has recently been reported in Africa, Asia, and the Pacific.

Until the early 1900s, N. americanus infestation was endemic in the southern United States and was only controlled after the widespread use of modern plumbing and footwear. Even though the prevalence of these parasites has drastically decreased in the general population, the CDC reports that in the United States, hookworm infection is the second most common helminthic infection identified in stool studies.14

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FIGURE 3.

Electron micrograph of teeth and cutting plate differences between (left) Ancylostoma duodenale and (right) Necator americanus .

Reprinted from Centers for Disease Control and Prevention and Dr. Mae Melvin. Accessed November 15, 2003, athttp://phil.cdc.gov.

FIGURE 3.

Electron micrograph of teeth and cutting plate differences between (left) Ancylostoma duodenale and (right) Necator americanus .

Reprinted from Centers for Disease Control and Prevention and Dr. Mae Melvin. Accessed November 15, 2003, athttp://phil.cdc.gov.

N. americanus ranges from 10 to 12 mm in length for females and 6 to 8 mm for males. It is distinguished from its slightly larger European cousin by its semilunar dorsal and ventral cutting plates at the buccal cavity compared with A. duodenale’s two pairs of ventral cutting teeth (Figure 3). The eggs of both worms are 60 to 70 μm in length and bounded by an ovoid transparent hyaline membrane; they contain two to eight cell divisions (Figure 4).

Both species share a common life cycle. Eggs hatch into rhabditiform larvae, feed on bacteria in soil, and molt into the infective filariform larvae. Enabled by moist climates and poor hygiene, filariform larvae enter their hosts through pores, hair follicles, and even intact skin. Maturing larvae travel through the circulation system until they reach alveolar capillaries. Breaking into lung parenchyma, the larvae climb the bronchial tree and are swallowed with secretions. Six weeks after the initial infection, mature worms have attached to the wall of the small intestine to feed, and egg production begins.

FIGURE 4.

Hookworm egg.

Reprinted from Centers for Disease Control and Prevention. Accessed November 15, 2003, athttp://phil.cdc.gov.

While larvae occasionally cause pruritic erythema or pulmonary symptoms during their migration to the gut,15 hookworm infection rarely is symptomatic until a significant intestinal worm burden is established. A transient gastroenteritis-like syndrome can occur because mature worms attach to the intestinal mucosa.

The greatest concern from infection is blood loss. Aided by an organic anticoagulant, a hookworm consumes about 0.25 mL of host blood per day. The blood loss caused by hookworms can produce a microcytic hypochromic anemia.16 Compensatory volume expansion contributes to hypoproteinemia, edema, pica, and wasting. The infection may result in physical and mental retardation in children. Eosinophilia has been noted in 30 to 60 percent of infected patients.

While clinical history, hygiene status, and recent travel to endemic areas can give important clues, definitive diagnosis rests on microscopic visualization of eggs in the stool.

E. histolytica

Amebiasis is caused by E. histolytica, a protozoan that is 10 to 60 μm in length and moves through the extension of finger-like pseudo-pods.1 Spreading occurs via the fecal-oral route, usually by poor hygiene during food preparation or by the use of “night soil” (crop fertilization with human waste), as well as by oral-anal sexual practices. Spreading is frequent in persons who have a deficient immune system. Crowding and poor sanitation contribute to its prevalence in Asia, Africa, and Latin America. Approximately 10 percent of the world’s population is infected, yet 90 percent of infected persons are asymptomatic.17 Of the roughly 50 million symptomatic cases occurring each year, up to 100,000 are fatal.18 The stable reservoir of infective cases complicates eradication. After malaria, it is likely that E. histolytica is the world’s second leading protozoan cause of death.19

Much like Giardia, the two stages in the E. histolytica life cycle are cysts and trophozoites (Figure 5). Infective cysts are spheres of about 12 μm in diameter that have one to four nuclei and can be spread via the fecal-oral route by contaminated food and water or oral-anal sexual practices. The pseudopodal trophozoite is about 25 μm across, has a single nucleus, and may contain red blood cells of the host in various stages of digestion. Ingested cysts hatch into trophozoites in the small intestine and continue moving down the digestive tract to the colon. Also like Giardia, some ameba trophozoites become cysts that are passed in the stool and can survive for weeks in a moist environment. However, trophozoites can invade the intestinal mucosa and spread in the bloodstream to the liver, lung, and brain.

Amebiasis can cause both intraluminal and disseminated disease. In the intestinal lumen, E. histolytica can disrupt the protective mucus layer overlying the colonic mucosa. The resulting epithelial ulcerations can bleed and cause colitis,20 usually two to six weeks after initial infection. Acute progression to malaise, weight loss, severe abdominal pain, profuse bloody diarrhea, and fever can occur, often leading to a misdiagnosis of appendicitis, especially in children. In chronic smoldering cases, inflammatory bowel disease can be misdiagnosed, and treatment with steroids only exacerbates the infection.

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FIGURE 5.

(Top) Entamoeba histolytica cyst and (bottom) trophozoite.

Reprinted from Centers for Disease Control and Prevention and Drs. L.L.A. Moore, Jr., and Mae Melvin. Accessed November 15, 2003, athttp://phil.cdc.gov.

FIGURE 5.

(Top) Entamoeba histolytica cyst and (bottom) trophozoite.

Reprinted from Centers for Disease Control and Prevention and Drs. L.L.A. Moore, Jr., and Mae Melvin. Accessed November 15, 2003, athttp://phil.cdc.gov.

Rarely, a reactive collection of edematous granulation and fibrous tissue called an ameboma can grow into the lumen, causing pain, obstruction and, possibly, intussusception. Toxic megacolon, pneumatosis coli (intramural air), and peritonitis also may occur.17,19

Tissue penetration and dissemination are possible. Trophozoites that penetrate the intestinal wall spread through the body via the portal circulation. Amebas are chemotactic, attracting neutrophils in the circulation. Amebic liver abscesses form because of toxin release and hepatocyte damage, and usually develop within five months after infection. Symptoms of a developing abscess include fever, dull pleuritic right upper quadrant pain radiating to the right shoulder, and pleural effusions. Diarrhea is present in only one of three patients with abscess. Fever is the presenting symptom in 10 to 15 percent of patients, and therefore amebic abscess should be considered in patients with a fever of unknown origin. Abscesses may rupture into the pleural space, peritoneum, or pericardium, requiring emergency drainage.

Traditional O&P stool testing for amebiasis should use at least three fresh samples to increase sensitivity. However, this test has recently fallen out of favor18 because an E. histolytica stool antigen test with a sensitivity of 87 percent and a specificity of more than 90 percent has become available.19 Stool culture and PCR testing modalities used in research are not yet sufficiently widespread to be clinically useful. Positive stool samples are likely to be heme positive and to have low neutrophils but may contain Charcot-Leyden crystals, indicating the presence of eosinophils. Biopsy of colonic ulcer edges may yield intramural trophozoites but carries with it the risk of perforation.

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FIGURE 6.

Computed tomographic scan showing liver abscess.

Reprinted with permission from Medscape. Accessed November 15, 2003, athttp://www.medscape.com/content/2002/00/44/12/441223/artiim441223.fig4.jpg.

FIGURE 6.

Computed tomographic scan showing liver abscess.

Reprinted with permission from Medscape. Accessed November 15, 2003, athttp://www.medscape.com/content/2002/00/44/12/441223/artiim441223.fig4.jpg.

Serologic tests such as ELISA and agar gel diffusion are more than 90 percent sensitive, but these tests often become negative within a year of initial infection. Approximately 75 percent of infected patients have leukocytosis, but mucosal invasion does not cause eosinophilia. Liver function tests usually are normal but may show minimal elevation of alkaline phosphatase, even in the presence of large abscesses. To avoid misdiagnosis, patients with suspected ulcerative colitis must be tested for E. histolytica antibodies before starting steroid therapy.17

Intestinal barium studies may be useful in identifying possible amebomas, but biopsy is required to confirm the diagnosis and rule out neoplasia. Liver imaging studies, such as ultra-sonography, computed tomography (Figure 6), magnetic resonance imaging, and nuclear medicine scans, can reveal abscesses as oval or round hypoechoic cysts, usually in the right lobe of the liver.21

Risk of complications increases with cysts of more than 10 cm, multiple cysts, superior right lobe involvement, or any left lobe involvement. Repeat studies may be confusing by showing larger abscesses in improving patients. Although two thirds of abscesses resolve within six months, approximately 10 percent of abscesses persist for more than a year.17

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TABLE 1

Treatment and Prevention of Parasite Infections

TABLE 1

Treatment and Prevention of Parasite Infections

Treatment and Prevention

Treatment and prevention strategies for parasite infections are summarized in Table 1.1,2,5,7,9,17,19,22  Amebicidal agents available in the United States are compared in Table 2.22

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TABLE 2

Advantages and Disadvantages of Amebicidal Agents

TABLE 2

Advantages and Disadvantages of Amebicidal Agents

Pinworms – Better Health Channel

What are pinworms?

The most common type of human worm infection in Australia is pinworm. Other names for this parasite include threadworm and Enterobius vermicularis, or the common term ‘worms’.

Children are more likely to pick up an infection than an adult, probably because of children’s tendency to put their fingers in their mouths. However, once a child is infected, other members of their household are also likely to get pinworms unless strict hygiene practices are observed. Infection can happen to anyone, regardless of a child’s home hygiene.

Despite the unsavoury reputation, a pinworm infection is relatively harmless and can be easily treated.

Worms require a host in order to survive. In the case of pinworms, the human acts as the host.

Life cycle of a pinworm

Infections begin when pinworm eggs are eaten, usually directly through contaminated hands or indirectly through contaminated food, bedding, clothing or other articles. The eggs then travel to the gut where they hatch and mature. A grown pinworm is yellowish white, slender and about one centimetre long.

Around 4 weeks after ingestion, the adult female moves down the gut and exits the body via the anus to lay a batch of eggs on the surrounding skin, often at night. The worm then dies, her reproductive mission complete.

The eggs may cause intense itching, especially at night, so children can easily reinfect themselves by scratching the anus and scraping eggs under their fingernails. These eggs can then be transferred to the mouth and the whole life cycle of the pinworm starts again. 

The eggs can survive on surfaces or objects (such as furniture, kitchen surfaces and toothbrushes) for up to 2 weeks in the right conditions and can infect other people if transferred to the mouth or food.

Household pets cannot be infected with pinworms or pass them on to humans.

Symptoms of pinworm

Pinworm infections often produce no symptoms but, when they occur, symptoms can include:

• itchy bottom, especially at night
• reduced appetite
• feeling mildly unwell
•  inflammation of the vagina
• adult worms can sometimes be seen in the faeces, and eggs may be seen clinging to the skin around the anus
• irritability and behavioural changes.

Treatment for pinworm infection

Your doctor might want to perform a test to make sure the problem is a pinworm infection. This is done by collecting the eggs from around the anus using sticky tape first thing in the morning. 

Medication is available to kill the worms and this is usually prescribed for the person who is infected and all other members of the household. One dose may be followed up with a second dose 2 weeks later to take care of any surviving worms.

Although the medication is safe for humans, you should consult your doctor or chemist before commencing treatment.

Preventing another pinworm infection

Suggestions to prevent another infection during treatment include:

• All family members should wash their hands and nails thoroughly with soap and water, particularly after going to the toilet, after changing nappies, before preparing food and before eating food.
• Discourage scratching of the bottom and nail biting.
• Keep fingernails short.
• Daily bathing and showering.
• Wash all sheets, bed linen, pyjamas and sleepwear in hot water to kill any pinworm eggs.
• Clean toilet seats and potties regularly with disinfectant (remember to store the disinfectant out of reach of children).
• All family members should take the medication, regardless of whether they are experiencing symptoms.

Where to get help

Parasitic Colitis

Clin Colon Rectal Surg. 2015 Jun; 28(2): 79–86.

, MD¹ and , MD, FACS, FASCRS²

Elizabeth M. Hechenbleikner

¹Department of Surgery, MedStar Georgetown University Hospital, Washington, District of Columbia

Jennifer A. McQuade

²Department of Colorectal Surgery, Virginia Hospital Center, Arlington, Virginia

¹Department of Surgery, MedStar Georgetown University Hospital, Washington, District of Columbia

²Department of Colorectal Surgery, Virginia Hospital Center, Arlington, Virginia

Address for correspondence Jennifer A. McQuade, MD, FACS, FASCRS Colorectal Surgery, Virginia Hospital Center, 1625 N. George Mason Drive, Suite 454, Arlington, VA 22205, moc.liamg@dmedauqcmjThis article has been cited by other articles in PMC.

Abstract

Over one billion people worldwide harbor intestinal parasites. Parasitic intestinal infections have a predilection for developing countries due to overcrowding and poor sanitation but are also found in developed nations, such as the United States, particularly in immigrants or in the setting of sporadic outbreaks. Although the majority of people are asymptomatically colonized with parasites, the clinical presentation can range from mild abdominal discomfort or diarrhea to serious complications, such as perforation or bleeding. Protozoa and helminths (worms) are the two major classes of intestinal parasites. Protozoal intestinal infections include cryptosporidiosis, cystoisosporiasis, cyclosporiasis, balantidiasis, giardiasis, amebiasis, and Chagas disease, while helminth infections include ascariasis, trichuriasis, strongyloidiasis, enterobiasis, and schistosomiasis. Intestinal parasites are predominantly small intestine pathogens but the large intestine is also frequently involved. This article highlights important aspects of parasitic infections of the colon including epidemiology, transmission, symptoms, and diagnostic methods as well as appropriate medical and surgical treatment.

Keywords: parasitic intestinal infections, protozoa, helminths, coccidia, ciliates, flagellates, amoebae, Chagas disease, nematodes, schistosomes

Parasitic enteric infections are a serious health burden in developing countries,¹² particularly among infants and children, and are common in Africa, Asia, and Latin American countries.³ In the United States, parasitic intestinal infections are generally uncommon without specific risk factors, such as traveling to endemic areas or having a compromised immune system.⁴ Protozoa and helminths are the two major classes of parasites that infect the human gastrointestinal (GI) tract causing a range of clinical outcomes from asymptomatic colonization to life-threatening illness. Protozoa are microscopic, unicellular organisms that invade cells and have different patterns of motility. In contrast, helminths are multicellular, worm-like organisms that reside inside the GI tract.⁵ Intestinal parasites are predominantly small intestine pathogens but the large intestine is also frequently involved.

Depending on the specific pathogen and the host’s overall health, parasitic intestinal infections can develop acutely with severe abdominal pain and fever mimicking appendicitis or in a chronic fashion with weight loss and diarrhea presenting like inflammatory bowel disease (IBD).⁶ In general, protozoa cause diarrheal illnesses, while helminths cause abdominal pain and can lead to intestinal obstruction or prolapse in individuals with a large burden of worms. In summary, parasitic intestinal infections are common worldwide causing tremendous morbidity. Most infections are self-limiting and respond to proper medical treatment while surgical intervention is reserved for complications of infection. This article highlights important aspects of parasitic infections of the colon including epidemiology, transmission, clinical presentation, and diagnostic methods as well as appropriate medical and surgical treatment.

Protozoal Infections

Protozoan enteric infections are caused by a diverse group of parasites including the coccidia, ciliates, flagellates, and amoebae, all of which result in diarrheal illness. In contrast, Trypanosoma cruzi infection (i.e., Chagas disease) causes constipation due to chronic colonic dilation and hypoperistalsis.⁷ The protozoan life cycle has two major stages: the cyst stage and trophozoite stage. Cysts are excreted in feces, have robust protective walls, and are responsible for the transmission of the parasite. The trophozoite stage generally occurs directly inside cells or hollow organs and is responsible for the intestinal pathology and clinical manifestations.

The Coccidia:

Cryptosporidium, Cystoisospora, and Cyclospora

Cryptosporidium, Cystoisospora, and Cyclospora cause the diarrheal illnesses cryptosporidiosis, cystoisosporiasis, and cyclosporiasis, respectively. Cryptosporidium species are found worldwide from Sub-Saharan Africa to the United Kingdom and Australia. Cystoisospora is common in the tropics and subtropics and Cyclospora is endemic in Haiti, Peru, China, and Nepal.⁸ All three diseases result from ingesting infectious oocysts which excyst to sporozoites, invade epithelial cells, and reproduce making more oocysts that are shed in feces.⁹ In contrast to Cystoisospora and Cyclospora, Cryptosporidium generates oocysts that stay inside the GI tract reinfecting epithelial cells (i.e., autoinfection) along with mature, infectious oocysts that are excreted with feces. Contaminated drinking or recreational water from infected humans or cattle is the main source of disease spread for Cryptosporidium. Oral–anal sexual practices also increase the risk of Cryptosporidium infection. In contrast, humans are the only hosts and reservoirs for Cystoisospora and Cyclospora, which are generally spread via contaminated water or food. Children and acquired immunodeficiency syndrome (AIDS) patients in developing countries are particularly vulnerable to intestinal coccidial infections, while sporadic waterborne outbreaks generally happen in developed countries.

Characteristically, patients present with profuse nonbloody, watery diarrhea along with nonspecific symptoms, such as abdominal pain, nausea, and/or sweats. The acuity and severity of diarrheal disease depends on the immunologic health of the patient. Immunocompetent patients usually present with acute, self-limiting symptoms whereas immunocompromised patients (e.g., AIDS patients) may have protracted and severe diarrheal disease resulting in malnutrition and weight loss. In addition, AIDS patients frequently develop extraintestinal problems including gallbladder and/or biliary tract infection.¹⁰

Coccidian protozoa usually parasitize small intestine epithelial cells but have also been found in the appendix, colon, and rectum, particularly in the setting of cryptosporidiosis. Characteristic histopathologic changes include an intense inflammatory response as well as blunting and atrophy of villi. Nonspecific mucosal abnormalities may be noted at the time of colonoscopy. Notably, cystoisosporiasis causes peripheral eosinophilia which is not seen with other coccidian parasites. Diagnosis can be confirmed by examining stool specimens for the presence of oocysts which may require concentration procedures (e.g., Sheather sugar flotation) and/or staining (e.g., modified Ziehl–Neelsen staining).¹¹¹² Polymerase chain reaction (PCR) diagnostic techniques are also available and are more sensitive. If fecal analyses fail, intestinal biopsies can be obtained for diagnosis.

Intestinal coccidial infections are treated with medical intervention. Treatment is initially aimed at properly rehydrating patients and addressing any nutritional needs. Nitazoxanide is used to treat cryptosporidiosis in immunocompetent adults and pediatric patients¹³ as well as AIDS patients with low CD4 counts (i.e., < 100 cells/µL).¹⁴ Patients with AIDS having very low CD4 counts (i.e., < 50 cells/µL) are less likely to respond to therapy and can progress to fulminant infection with high mortality.¹⁵ Trimethoprim/sulfamethoxazole (TMP-SMX) is the treatment of choice for cystoisosporiasis and cyclosporiasis. It is imperative to optimize highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV) patients, particularly for cryptosporidiosis for which HAART is the cornerstone of therapy.

The Ciliates and Flagellates:

Balantidium coli and Giardia lamblia

The ciliate, Balantidium coli, and flagellate, Giardia lamblia, are responsible for the protozoan illnesses known as balantidiasis and giardiasis, respectively. B. coli infection is frequently asymptomatic and is more limited in its geographic distribution compared with G. lamblia. Balantidiasis is relatively uncommon in humans and largely confined to the tropics and subtropics. Unlike the intestinal coccidial infections, balantidiasis is not typically seen in immunocompromised patients.¹⁶

Pigs are the major reservoir for B. coli and infection is common in areas with poor sanitary conditions where public water supplies are contaminated with pig feces. Once humans ingest infective cysts, excystation occurs and trophozoites colonize the large intestine and may invade the colonic wall. Trophozoites then undergo encystation and mature cysts are excreted in feces. Human-to-human spread of B. coli infection is possible, albeit much less common. Balantidiasis may present in a similar fashion to amebiasis (E. histolytica infection) with acute abdominal pain, bloody diarrhea, and colon ulceration.¹⁷ Surgical intervention is reserved for serious complications, such as bleeding and perforation.¹⁸ Microscopically, trophozoites can be easily identified in wet mount preparations of freshly collected diarrhea while cysts are found in normal, formed stool samples. Colon biopsies can also be used to identify the parasite and determine the amount of inflammation and damage to the intestinal wall.¹⁶ In adults, medical treatment with tetracycline or metronidazole typically resolves balantidiasis.¹⁴

In contrast to balantidiasis, giardiasis is one of the most common protozoan diarrheal illnesses in humans and is frequently found in other animal species.¹⁰ The presence of HIV infection does not appear to increase the risk of infection. In the United States, G. lamblia is the most prevalent protozoan parasite.¹⁹ Giardiasis is transmitted mainly by ingesting contaminated water but can be passed between humans or, less commonly, contracted from infected animals. After ingestion of infectious cysts, trophozoites multiply in the small or large intestine either staying in the lumen or attaching to the epithelium without mucosal invasion. Similar to cryptosporidium, cysts are immediately infectious after being excreted in feces; hence, giardiasis is easily passed between household members or in day care centers. In developing countries, infection can become rampant in areas of crowding and poor sanitation.

Clinically, G. lamblia infection can result in asymptomatic colonization, acute diarrhea, chronic diarrhea with malabsorption and weight loss, or nonspecific GI complaints (e.g., dyspepsia).²⁰²¹ Acute diarrhea is usually self-limiting and frequently accompanied by cramping, bloating, and steatorrhea. In the chronic setting, giardiasis can negatively affect growth and cognitive development in children and has been included in the World Health Organization’s Neglected Diseases Initiative.²² Microscopic examination of stool samples is commonly used to make the diagnosis. Similar to balantidiasis, cysts are almost always found in formed stool while trophozoites are excreted in diarrhetic fecal samples. Enzyme-linked immunosorbent assays (ELISA) to detect serum antibodies against G. lamblia are also available and are very sensitive. If stool and serum studies fail to make the diagnosis, duodenal aspirates or biopsies may be obtained. Treatment is generally the same regardless of the patient’s immunologic status and is predicated on whether symptoms are present.⁶ The preferred antiparasitic agents are tinidazole or metronidazole.¹⁴ In developing countries, reinfection rates are high thus treatment of asymptomatically colonized patients may not be worth the cost.

The Amoebae:

Entamoeba histolytica

Entamoeba histolytica is an invasive colon pathogen found globally but concentrated in Central and South America, Africa, and India.²³E. histolytica moves and feeds with pseudopodia or “false feet” and is transmitted via the fecal–oral route; humans are the predominant reservoir and host. The life cycle is similar to that of B. coli; while extraintestinal spread is rare in balantidiasis, E. histolytica invades the mucosa causing ulceration, spreads in the bloodstream, and commonly infects other organs. E. histolytica infection has three clinical scenarios: (1) asymptomatic colonization, (2) intestinal amebiasis, or (3) extraintestinal amebiasis. In extraintestinal amebiasis, the most common infection is a liver abscess, but brain and splenic abscesses may develop. Intestinal amebiasis commonly presents with abdominal pain, tenesmus, fever, and bloody diarrhea with mucus. Intestinal symptoms that develop abruptly in children and immunocompromised patients are often misdiagnosed as appendicitis.⁶ Despite the rarity of amebic acute appendicitis, it is a possibility and predominantly occurs in regions where the risk of amebiasis is high.²⁴ Serious complications include hemorrhage from ulceration, peritonitis due to perforation,²⁵ toxic megacolon,²⁶ and fulminant colitis which frequently require urgent surgical exploration and intestinal resection. In the setting of fulminant colitis, the colon can be extremely friable and difficult to manipulate due to extensive necrosis.²⁷

Diagnosis can be made via microscopic examination of stool to identify trophozoites or cysts but this is mainly done in places where updated techniques are not available. Currently, serologic assays (e.g., indirect fluorescent antibody test) and the detection of E. histolytica antigens in stool are the preferred diagnostic methods. Conventional and real-time PCR tests are available but are more expensive.²⁸ In addition, colonoscopy may aid in the diagnosis; biopsies of ulcerated colon tissue may demonstrate trophozoites ().⁶ Notably, deep, flask-shaped ulcers are common in amebiasis and can be mistaken for ulcerative colitis (UC) during colonoscopy.²⁷ In the setting of presumed UC, patients may mistakenly receive steroid treatment which can lead to hyperinfection and have fatal consequences.²⁹ For intestinal amebiasis, treatment with metronidazole or tinidazole should be followed by a luminal agent, such as iodoquinol or paromomycin.¹⁴ Liver abscesses usually respond to metronidazole and do not require drainage.²⁷

Entamoeba histolytica trophozoites in the intestinal tissue stained with hematoxylin and eosin.

Chagas Disease:

Trypanosoma cruzi

Trypanosoma cruzi is the parasite that causes Chagas disease, infecting humans and other mammals. The disease is also known as American Trypanosomiasis because it is endemic in parts of Latin America, particularly Brazil, Argentina, and Mexico, where millions of people are infected. In the United States, over 300,000 people are likely to suffer from Chagas disease.³⁰ Transmission is predominantly vector borne through infected triatomine bugs which are almost exclusively found in Latin America. During a bite, the triatomine vector defecates and infective metacyclic trypomastigotes enter the host’s bloodstream. Other less common routes of transmission include congenital, blood borne, and oral; solid organ donors can also transmit T. cruzi to recipients.³⁰

Upon entry into the host, trypomastigotes invade a variety of cell types becoming amastigotes where they multiply, become trypomastigotes again, and spread throughout the body. Chagas disease has both acute and chronic presentations. In the acute setting, localized redness and swelling are commonly noted at the triatomine bite wound. As the parasite spreads systemically, patients may develop generalized lymphadenopathy and complain of fevers and fatigue. Acute Chagas disease is diagnosed via microscopic visualization of parasites in blood smears and typically resolves within 8 weeks.³¹ Upon resolution of the acute phase, patients may transition into an asymptomatic disease state for years before developing end-organ dysfunction. Chronic Chagas disease predominantly causes cardiac and GI complications. In chronic disease, serodiagnostic assays are used to identify IgG antibodies to T. cruzi.⁷ Treatment is recommended for asymptomatic adults with chronic Chagas disease, particularly women of child-bearing age. The most common medications used to treat Chagas disease are benznidazole and nifurtimox.¹⁴

GI complications are heavily focused in South American countries.³² Megaesophagus is the most common GI problem but megacolon also develops.⁷ The distal aspects of the colon and rectum appear to be the most affected, which can be demonstrated on barium enema or other radiographic studies.³² The pathogenesis involves thickening of the intestinal wall, degeneration of neurons, progressive dilation, ineffective peristalsis, constipation, and ultimately megacolon (). The abnormally dilated colon can also present as a volvulus. Patients with constipation should initially be treated with increased dietary fiber and water intake, laxatives, and enemas. Apart from surgical emergencies (e.g., volvulus), elective resection is offered to patients with chronic, debilitating symptoms who fail conservative treatment. Surgical options include rectosigmoidectomy with ileal loop interposition³³ or the Duhamel–Haddad operation which involves a sigmoidectomy followed by sewing the descending colon to the posterior aspect of the rectal stump.³⁴

Representative drawing of a patient with abnormally dilated loops of large intestine due to chronic Chagas disease.

Helminth Infections

Helminths are macroscopic parasites with complex life cycles infecting billions of people worldwide.⁹ Nematodes and schistosomes are responsible for the majority of human helminth infections. A subset of nematodes is called soil-transmitted helminths (STHs), including Ascaris lumbricoides, Trichuris trichiura, and Strongyloides stercoralis. In contrast, Enterobius vermicularis is an intestinal nematode that does not require a soil phase for transmission. Schistosomes are parasitic flatworms commonly referred to as flukes. STHs are found in the tropical climates of Africa, Asia, and Latin America and schistosomes are common in the Middle East, South America, Africa, and Asia.³⁵E. vermicularis is found in both tropical and temperate climates around the world.

Soil-Transmitted Helminths:

Ascaris lumbricoides

Ascaris lumbricoides causes the intestinal illness known as ascariasis. Over 800 million people are estimated to be infected with the Ascaris roundworm.³⁶ In developing countries, ascariasis is very common resulting in impaired growth, cognitive development, and decreased school attendance particularly among preschool-aged children and adolescents.³⁷ In the United States, ascariasis is rare but tends to occur in the rural Southeast³⁸ and in immigrants³⁹ from the developing world. Patients with HIV do not appear to be at increased risk for infection.⁴⁰

Infection occurs when embryonated Ascaris eggs are ingested from contaminated food and/or water. Characteristically, eggs are shed in the feces of infected individuals into the soil where they mature over a few weeks to become infectious. Upon ingestion, eggs hatch into larvae in the small intestine where they penetrate the intestinal wall to enter the bloodstream and travel to the lungs. In the lungs, the larvae ascend the respiratory tract and are swallowed back into the GI tract. The majority of adult worms are found in the jejunum and ileum and can grow to over 30 cm. Female worms produce thousands of eggs each day which are shed in feces. Diagnosis is made via microscopic visualization of eggs in fecal samples.

Most people who are infected with Ascaris worms have no symptoms. In patients with ascariasis, symptoms range from minimal GI complaints to severe abdominal pathology.⁴¹ Surgical complications of ascariasis are frequent in children. Patients with a large worm burden are more likely to have intestinal symptoms and may present with obstruction, perforation, intussusception, and/or bowel necrosis requiring emergent surgical intervention.⁴²Ascaris worms can also migrate into the appendix causing acute appendicitis.³⁹ In adult women, biliary and pancreatic complications are common. Adult worms can obstruct the extrahepatic biliary tree resulting in complications, such as cholangitis, pancreatitis, and hepatic abscess.³⁶ Abdominal computed tomography, plain films, and ultrasound are useful diagnostic modalities for establishing intestinal and/or biliary complications of ascariasis.⁴³⁴⁴ Effective anthelminthic agents include albendazole and mebendazole.

Soil-Transmitted Helminths:

Trichuris trichiura

Whipworm or Trichuris trichiura infection affects an estimated 600 to 800 million people globally.³⁶ Similar to Ascaris, T. trichiura eggs take several weeks to embryonate in soil and cause infection upon ingestion from contaminated food or water. In contrast to ascariasis, trichuriasis is a disease of the large intestine. Once the Trichuris eggs are ingested, larval maturation preferentially happens in the cecum and there is no migration to extraintestinal sites. Mature whipworms attach themselves to the epithelial surface causing inflammation and colitis which, in serious infections, can affect the entire colon and rectum ().⁴⁵

Adult Trichuris trichiura worms in hemorrhagic colon mucosa.

The majority of individuals infected with T. trichiura are asymptomatic or have minimal symptoms. Some patients with trichuriasis present with symptoms similar to IBD, such as bloody diarrhea, anemia, and abdominal pain. Serious complications, such as rectal prolapse, are more likely to happen with heavy worm infections and may require surgical intervention.⁴⁶ Microscopic visualization of Trichuris eggs from fecal samples confirms the diagnosis but may require concentration procedures. If noninvasive tests fail, endoscopy allows for direct visualization of Trichuris worms, assessment of the severity of colitis and/or proctitis, and removal of worms.⁴⁷ A short course of an anthelminthic agent, such as albendazole and mebendazole, is usually sufficient to eradicate infection.¹⁴

Soil-Transmitted Helminths:

Strongyloides stercoralis

Strongyloides stercoralis is estimated to infect up to 100 million people worldwide.⁴⁸ Studies reporting the prevalence of strongyloidiasis in the United States are outdated but historically infection has been endemic in subregions of Appalachia.⁴⁹ In contrast to other STHs, S. stercoralis infection results from infective larvae penetrating the skin, which usually happens in the feet while walking barefoot on the soil. Infective larvae enter the bloodstream traveling to the lungs where they mature, ascend the respiratory tree, and are swallowed. Female larvae typically burrow into the intestinal wall in the duodenum and jejunum and release eggs. The eggs hatch into noninfective larvae which are shed in feces contaminating the external surroundings. In the soil, noninfective larvae become infective either via direct development or through the release of eggs that hatch and mature into infective larvae.⁴⁸

Strongyloidiasis can affect various areas of the body including the GI tract, kidneys, alveoli, meningeal space, skin, and joints. In the GI tract, noninfective S. stercoralis larvae can become infective, invade the colonic mucosa, and cause an inflammatory pattern that mimics IBD, particularly UC.⁵⁰S. stercoralis colitis may demonstrate aphthoid ulceration on colonoscopy, absence of haustra on radiographic studies, and/or peripheral eosinophilia.⁵¹ Disseminated strongyloidiasis is a rare form of S. stercoralis hyperinfection which spreads to multiple organs and is almost always fatal. In addition, the risk of strongyloidiasis appears to be increased in HIV/AIDS patients as well as patients with human T-cell lymphotropic virus type I (HTLV-I).

The diagnosis is typically made by visualization of larvae on wet-mount preparation of stool, which may require concentration procedures and/or multiple samples. S. stercoralis colitis is confirmed by identifying larvae in biopsy samples.⁵¹ The preferred drug for treatment is ivermectin but albendazole is a suitable alternative.

The Common Pinworm:

Enterobius vermicularis

Enterobiasis or pinworm infection is caused by Enterobius vermicularis and is estimated to infect at least one billion people globally. Enterobiasis is the most common intestinal helminth infection in the United States.⁵² Humans are believed to be the only host for E. vermicularis. Children suffer the burden of most pinworm infections with an estimated 4 to 28% of this age group affected worldwide.⁵³ Enterobiasis is passed easily among people living in close quarters particularly institutionalized patients and household members who cobathe or share sleeping space.

E. vermicularis‘ eggs are ingested and hatch into larvae in the small intestine. The larvae migrate to the large intestine residing largely in the cecum and appendix. Adult and female larvae mature and mate inside the GI tract. The gravid adult females travel to the perianal region at night laying eggs which can cause intense itching. The eggs become infective within 6 hours and get deposited on clothes, sheets, and under fingernails when the host scratches the perianal region. Finger sucking and nail biting can result in autoinfection.⁵⁴ Although pruritus ani is the most common symptom, acute appendicitis is also frequently associated with enterobiasis in the pediatric population due to adult worms migrating into the appendix ().⁵⁵ Diagnosis is different from other intestinal nematodes because E. vermicularis‘ eggs are uncommonly shed with feces. The Scotch tape test, either done at night or early in the morning, is the best way to make the diagnosis. Briefly, scotch tape is pressed against the perianal region and then placed on a glass slide to visualize eggs under a microscope.⁵⁶ Medical treatment with albendazole or mebendazole is usually highly effective. Of note, following appendectomy for parasitic appendicitis, patients should undergo medical treatment to ensure pinworm infection is completely cleared.

Section from appendectomy specimen demonstrating intraluminal Enterobius vermicularis worms.

Schistosomiasis:

Schistosoma

Schistosomiasis is caused by a diverse group of Schistosoma species or trematodes and is estimated to infect 200 million people worldwide.⁵⁷ Schistosomiasis is a significant health and economic burden in developing, impoverished nations where early childhood infection is common. Three predominant species infect humans, including S. haematobium, S. mansoni, and S. japonicum. S. haematobium and S. mansoni are endemic throughout parts of Africa, while S. japonicum is highly prevalent in China and the Philippines.

Humans are infected in freshwater when they come in contact with cercarial larvae from intermediate snail hosts. These free-swimming larvae penetrate the skin while the host is swimming or bathing which may result in an itchy rash. Once in the bloodstream, the larvae become schistosomulae, enter the mesenteric and portal circulation, mature to adult form, and migrate to various organs laying eggs. Ultimately, S. haematobium eggs are excreted in the urine while S. mansoni and S. japonicum eggs are shed with feces contaminating freshwater sources. The eggs hatch into miracidia larvae which then infect snails to restart the life cycle.⁵⁸

Acute and chronic sequelae happen as a result of the deposited eggs. Chronic sequelae are more likely to develop in endemic areas of infection. In the acute setting, the initial immune response results in nonspecific, generalized findings, such as peripheral eosinophilia, fever, and organomegaly (Katayama fever). In the chronic setting, inflammation and fibrosis cause varying degrees of organ injury.⁵⁸S. haematobium infects the urogenital tract; eggs get deposited in the ureters and bladder which can cause dysuria, hematuria, bladder outlet obstruction, and renal failure. In contrast, S. mansoni and S. japonicum infect the liver and GI tract. In the liver, eggs localize to the inferior mesenteric and portal veins leading to portal hypertension, hepatic dysfunction, and hematemesis.⁵⁹⁶⁰ In GI schistosomiasis, eggs are deposited in the intestinal submucosa causing abdominal pain and bloody diarrhea, and chronic colitis, ulceration, stricturing, and inflammatory polyps may also develop.⁶¹

The diagnosis of schistosomiasis can be made by visualizing eggs under a microscope from urine or fecal samples as well as biopsies from the GI or urogenital tracts. ELISA techniques are also available for detecting antischistosomal antibodies in the blood but cannot differentiate between active or previous infection. The mainstay of medical therapy is praziquantel¹⁴ and is estimated to clear infection in 60 to 90% of the patients.⁵⁷ Surgery for GI schistosomiasis is reserved for complications, such as bleeding, perforation, and stricturing.

Conclusion

Parasitic intestinal infections are a serious global health burden, particularly in developing countries, and can have a detrimental effect on growth and cognitive development in children. GI parasites have a broad spectrum of clinical manifestations from asymptomatic colonization to overwhelming sepsis. Medical therapy is the mainstay of treatment while surgical intervention is reserved for complications of infection, such as perforation, bleeding, or fulminant colitis.

The World Health Organization has included protozoal (i.e., Chagas disease) and soil-transmitted helminth GI infections in their neglected tropical diseases initiative which is aimed at eliminating tropical infections with widespread deleterious effects. Mass drug administration of antiparasitic agents to endemic areas of infection has drastically improved but still has challenges; continued funding, epidemiological and drug research, and logistical support are required to sustain the delivery of proper medical care to those who most need it. Improved diagnostic techniques and vaccines offer additional opportunities in the global fight against pathogenic GI parasites.

Acknowledgments

The authors thank Mr. Ronald Neafie, MSc, Parasitologist, and Dr. Mary Klassen-Fischer, MD, Pathologist with The Joint Pathology Center in Silver Spring, MD, for assistance with acquisition of images.

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Diagnostics of helminths

I cannot but appeal to the audience reading us about different options for parasitological research.

With a clinical suspicion of a parasitic disease in children and adults, diagnosis can be carried out by examining feces for helminth eggs and scrapings for enterobiasis. To expand diagnostic capabilities, a blood test for some types of helminths allows: hepatic flukes, ascariasis, giardiasis, and for the presence of tissue helminths (toxocara, echinococcus and trichinella), when antibodies to these parasites are determined in a blood test.

I must say that none of the methods has 100% accuracy, and there is no 100% guarantee for negative results either. Many laboratory tests must necessarily be correlated with clinical data. Analyzes need to be performed multiple times, increasing the likelihood of getting the correct result. The difference in diagnostic capabilities depends on the specificity of helminths. So, if the helminth in the body is in the tissues, then eggs in the feces of a person cannot be detected. Some “prolific” parasites release many eggs into the environment, but release them in different places and cyclically.For example, the female roundworm secretes eggs in large numbers into the intestinal lumen, and in the feces they are often searchable, while pinworms secrete eggs only in the perianal region of a person, and they can be detected by scraping with adhesive tape. Against the background of various circumstances and life cycles of parasites, the release of eggs does not occur every day, which means that it is not always possible to detect eggs in feces or in scrapings from the perianal region. Therefore, helminthiases are not easy to detect, they require repetition of studies up to 3 times, or to increase the sensitivity of diagnostic methods, PCR diagnostics of feces is carried out to detect even “traces” of helminths (ie.e. detection of the DNA of the parasite).

If suspicious inclusions are found in the feces (something similar to a parasite), describe to the doctor, photograph the inclusions, bring them to the laboratory for research and correlate with clinical complaints. Only after carefully analyzing all the information, the doctor will prescribe treatment, conduct an epidemiological investigation and monitor the result of therapy.

The prevalence of helminthiasis is high, the detection rate is low, we will talk about prevention and preventive treatment later.

Worms (helminthiasis): Symptoms, diagnosis and treatment

Worms – worms leading a parasitic lifestyle in the body of their host – a person. Age doesn’t matter. Both adults and children are equally susceptible to infection. The classification of helminthiases is very extensive, especially in countries with hot climates.

There are 3 classes of parasitic worms:

• round (nematodes) – pinworms, roundworms;
• tape (cestodes) – pork tapeworm, bovine tapeworm, echinococcus;

90,021 flatworms, flukes (flukes).

The most common worms in children are pinworms, which cause enterobiasis. These helminths are small in size, on average up to 1 cm, white-gray in color with a curved body. The place of localization of these parasites is the large intestine, but they can also penetrate into the lower parts of the small intestine. Pinworms reproduce on the skin near the anus. At night, female pinworms get out to lay eggs in the folds of the skin, often penetrating the labia of girls, which ends with infectious diseases of the genitals.In total, these helminths live for about 1-1.5 months. The process of self-infection in a child can lead to the fact that the malaise will continue for many years. Parasites can be detected with the naked eye in the feces.

Another type of worms most common in children is roundworm. A characteristic species, reaching a length of 15 cm, these nematodes settle in the lumen of the loops of the small intestine, moving towards the moving food lump. Roundworms enter the feces very rarely. Females periodically release eggs, which can be found in feces analysis.But if during the study they were not found, this does not mean that the child is not infected. The life cycle of a roundworm can last for several years.

Reasons

The kid’s curiosity is realized by his fingers, the child, learning about the world, actively touches everything that comes under his arm and immediately pulls into his mouth, trying for strength and taste. Thus, pinworm eggs safely enter the digestive tract of their future little host.

A child becomes infected with worm eggs from the surface of unwashed fruits when drinking contaminated water.Very often, infection occurs when communicating with animals, or when playing in the ground, sandpit, where cats and dogs like to solve their physiological problems. After a walk, children often do not wash their hands, and all the dirt, along with parasitic eggs, gets into their mouths.

Symptoms

If a child has been infected with a large number of eggs of parasitic worms, then a sharp deterioration may occur in a few days. In milder cases, the first symptoms of invasion appear after several weeks or even months.Much depends on the child’s immunity. He may well cope with parasites and restrain their development. But gradually the defenses are reduced, and helminths infect the body, causing serious problems.

Symptoms of poisoning (intoxication) are the first signs. The vital activity of worms is accompanied by the release of a large number of animal toxins that can poison the child’s body. In the intestines, parasitic worms use nutrients, as a result of which the baby gradually becomes deficient in proteins, carbohydrates, fats and vitamins.

The child has:

• emaciation,
• pallor of the skin,
• weakness, frequent dizziness,
• rise in body temperature, headache,
• bad dream,
• tearfulness,
• depressed mood.

Intestinal ailments are manifested – constipation, loose stools, rumbling and pain in the abdomen, bouts of nausea and vomiting, painful sensations in different parts of the abdomen, bloating.The disease can be accompanied by allergic conditions: itching, rashes, cough, inflammation of the mucous membranes of the respiratory tract. Weakening of immunity leads to the addition of infectious diseases.

Diagnostics and treatment

Diagnosis of helminthiasis in feces is rather difficult. This is due to the fact that roundworm eggs or pinworms do not appear in the feces every day, and the technique of smear microscopy from the analysis requires great care. To increase the reliability of the analysis of feces for eggs of worms, it is advisable to take at least 3 days in a row.

In cases of increased risk of infection with worms (contact with animals, the child’s playing on the ground or in open sandpits, the child’s habit of taking things in his mouth, biting his nails or licking his fingers, etc.), it is advisable to undergo an in-depth examination, including, in addition to three-fold analysis of feces special blood tests that detect antibodies to helminths.

In the presence of allergic manifestations of unknown origin, an increase in the number of eosinophils in the blood test, persistent intestinal dysbiosis, it is advisable to donate blood for the determination of class E immunoglobulins (Ig E and G) to roundworm and other helminths.You can check for worms in pets.

Assessing the totality of indirect signs and anamnesis, the doctor can recommend antihelminthic therapy without direct evidence of the presence of worms in the child, if other pathologies that cause similar clinical manifestations are excluded.
If worms are found in a child or in one of the family members, it is necessary, if possible, to treat all family members in order to avoid the formation of a focus of infection with each other with helminth eggs.In this situation, in addition, it is necessary to strengthen hygiene measures, in particular, to boil and iron bed and personal linen on both sides.

90,000 Analysis for enterobiasis (pinworm eggs, enterobiasis), swab

Method of determination
Microscopy.

Study material
Scraping

Home visit available

Enterobiasis – helminthiasis, the clinical manifestations of which are perianal itching and intestinal disorders.

The causative agent is a pinworm (Enterobius vermicularis or Oxyuris vermicularis). This is a small nematode that lives in the large intestine, and crawling out of the rectum, it lays eggs in the folds at the anus. The source of infection is a sick person.

The mechanism of infection is fecal-oral (“dirty hands” disease). Pinworm larvae, attaching to the skin, cause inflammation, and mature worms disrupt the motor and secretory functions of the intestine. The waste products of these worms and, especially, their decay products have a toxic and allergic effect.Eosinophilia, metabolic disorders and vitamin deficiencies are often observed.

We draw your attention to the need to purchase a kit for taking the material (a plastic test tube with a cotton swab in glycerin), which, together with the instructions, must be purchased in advance at any INVITRO office on bail. The return of the collateral is carried out upon the delivery of the analysis and subject to the availability of a check for posting the collateral.

Attention! The possibility of taking biological material in the medical office and the cost of this service, check with the operators of the Federal Information Service by phone:

8 (495) 363-0-363, 8 (800) 200-363-0.

Literature

1. Human parasitic diseases (protozoses and helminthiases). A guide for doctors. Ed. Sergeeva V.P., Lobzina Yu.V., Kozlov S.S. SPb., 2006.586 p.
2. Guide to Medicine (Ch. Ed. R. Berkow) – M. – Mir 1997, vol. 1 pp. 142 – 163.
3. Wallach J. Interpretation of diagnostic test Lippincott – 2000 pp. 864 – 885.

Enterbiosis: routes of infection, symptoms, diagnosis and treatment

Enterobiasis is a disease caused by parasites (helminths), roundworms and small nematodes – pinworms.

With the naked eye, you can mainly see only female pinworms, the length of which is slightly more than one centimeter. Male pinworms are about 5 times smaller in size, and without a certain skill they are difficult to notice.

Why did we decide to draw your attention to this, probably, the smallest type of parasitic worms?

In general, in nature, unfortunately, there is a fairly large number of different parasites with which a person can become infected, for example, from dogs – toxocars, or by eating unwashed, contaminated fruits and vegetables – roundworms, or poorly fried or cooked beef or fish, and so In this way, you can pick up tape chains or opisthorchiasis.

But fortunately, thanks to the high-quality work of the sanitary services, many of the listed parasites have become a rarity, but ordinary, and almost invisible pinworms have not become a rarity.

In Soviet times, people of the older generation remember that children in kindergartens were given a drug against worms twice a year without fail, since regularly conducted studies showed that at least 2 – 3 percent of children attending kindergarten were permanently infected with pinworms.

Enterobiasis, route of infection

Pinworms enter the human body through the fecal-oral route, that is, through unwashed hands after using the toilet, or through contaminated food and household items. Children are more often infected, inclined to try all new objects “to the teeth”. In organized children’s groups, a lot depends on the attentiveness of educators, who force their wards to wash their hands before eating, but it is also impossible to remove responsibility from parents, because, as you know, the best upbringing is their own example for the younger generation.

Enterobiasis, clinic, symptoms

The first symptoms of enterobiasis appear two weeks after infection. During this time, small pinworms “hatch” from the helminthic eggs that have entered the intestines and grow to a sexually mature individual. And then they begin to reproduce. The severity of the disease, among other things, also depends on the number of ingested parasites. In the case of the development of a very large number of parasites in the intestine, the disease can be severe. The same effect is exerted by the duration of helminthic invasion.In most adult patients, who have mastered hygiene skills since childhood, accidental infection, as a rule, ends with self-recovery after 2 – 3 months. The situation is different with children.

The most common complaints of pinworm infestation are burning and itching in the anus, which most of all disturb at night, in the morning, become unbearable, spread to the perineum, genitals, thighs, abdomen. Children suffering from enterobiasis become nervous, their appetite significantly deteriorates, weight loss is observed, and the child may cry involuntarily at night.

In adults and children with severe helminthic invasion, diarrhea can be observed, sometimes with an admixture of mucus and blood, nausea, vomiting, bloating, and sometimes, on the contrary, constipation, up to the development of intestinal obstruction, requiring surgical treatment.

Enterobiasis, diagnostics

The diagnosis of enterobiasis can be assumed by the presence of itching in the anus and the release of pinworms in the feces. True, perianal itching can sometimes be caused by food allergies or irritation of the skin around the anus in case of intestinal disorders.The decisive role in the diagnosis of enterobiasis is played by the results of laboratory studies of scraping from the folds located around the anus. Pinworm eggs can be removed from the perianal folds with adhesive plastic tape, or with a cotton swab dipped in glycerin. The study for enterobiasis should be three times, since with a single study the detectability of enterobiasis does not exceed 50%.

In any case, it does not hurt at all for your own peace of mind to take this analysis at least twice a year, especially if there are several children in the family.Remember that enterobiasis, for all its simplicity, can be a very serious problem, be the cause of many disorders both on the part of the digestive system, and in some cases cause an exacerbation of allergic diseases, and in long-term neglected cases, even a reason for surgical intervention. Teach your kids hygiene skills and get tested regularly!

Analysis for worm eggs. How to donate feces for me / worm

Author

Minchenkova Evgeniya Vladimirovna

Leading physician

Pediatrician

Worms are parasitic worms that live in the human body.The life cycle of many worms is designed in such a way that their eggs must enter the external environment (this is a necessary condition for their maturation). From the human body, eggs are released outside together with feces. Therefore, with helminthic invasion, the likelihood of finding helminth eggs in the feces is quite high.

When is feces taken for analysis for worm eggs?

Analysis of feces for eggs of worms is necessary in the following cases:

Preparation for analysis for worm eggs

Preparation for the analysis consists in the exclusion of factors that can distort the results of the study.For several days before the study, you should not use:

• castor oil;
• preparations containing bismuth and magnesium;
• antidiarrheal drugs;
• antibiotics.

How to donate feces for eggs of worms?

Feces should be collected in a special container. If a pot or vessel is used to collect material, it should first be washed well with soap and rinsed.

The bowel movement should be natural, without the use of enemas or laxatives.Care must be taken to ensure that no urine enters the collected material.

For analysis, a volume equal to 1-2 teaspoons is sufficient. It is advisable to collect material from different parts of the feces (this will increase the likelihood of detecting worm eggs in case of damage).

Feces can be collected in the evening, and taken to the laboratory in the morning. In this case, the container with the collected material should be stored in the refrigerator. It is optimal to deliver the collected material to the laboratory within 3 hours.

The result of the analysis of feces for eggs of worms

Norm: eggs of worms in the feces should be absent. If the eggs, the worms themselves or their fragments are found, their identification is carried out (the type of worms is established).

In order for a negative result to be considered truly confirmed, it is advisable to pass the test three times (at intervals of several days).

The most common worms – pinworms – are usually not detected with this analysis.To detect enterobiasis (pinworm infection), another analysis is used – scraping from the folds of skin around the anus (scraping for enterobiasis).

If the result of the analysis of feces for eggs of worms turned out to be negative, but suspicions of helminthic invasion (infection with worms) persist, an enzyme-linked immunosorbent assay (ELISA) may be prescribed, which allows detecting antibodies to parasites of various types.

Where to make an analysis for eggs of worms in Moscow?

You can make an analysis of feces for eggs of worms in JSC “Family Doctor”.You can hand over the material for analysis in any of our clinics, choosing the one that is located in the district of Moscow you need. If you need to do an analysis for the eggs of worms urgently, you can take the analysis at the Polyclinic №15 (metro station Baumanskaya) in CITO mode.

Do not self-medicate. Contact our specialists who will correctly diagnose and prescribe treatment.

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synlab: FALSE TESTS

Many diseases of the gastrointestinal tract require specific diagnostics.In recent years, reliable tests have been developed to determine fecal parameters. These tests provide useful information for the differential diagnosis of pathological conditions. The surface of the mucous membrane of the human gastrointestinal tract (GI) is about 200-300 m² and is colonized by 10¹³¯¹⁴ bacteria of 400 different species and subspecies.

SINLAB offers stool tests:

– Pancreatic elastase-1
– Coprogram
– Determination of Clostridium difficile toxins A and B
– Giardia
– Determination of Helicobacter pylori antigens
– Determination of helminth eggs
– Calprotectin
– Occult blood in feces
– Complex: hidden blood, transferrin , calprotectin, lactoferrin
– Scraping for enterobiasis

Feces are the end product of digestion, which consists of undigested food particles, digestive juices, intestinal mucosa cells and bacteria.
Coprogram involves the study of the general properties of feces, chemical and microscopic examination.
– Physical indicators: shape, consistency, color, odor, mucus
– Biochemical indicators: pH, bilirubin, stercobilin
– Microscopic examination: connective tissue, muscle fibers, neutral fat, soaps, fatty acids, vegetable fiber, starch, iodophilic bacteria, mucus, leukocytes, erythrocytes, epithelium, protozoa, yeast-like fungi.

Determination of hemoglobin and transferrin in human feces.
The aim of this study is to identify gastrointestinal bleeding, which can be an indicator of diseases in both the lower and upper gastrointestinal tract.
Determination of occult blood is an effective method for the early diagnosis of colorectal cancer.
The presence of blood in the feces may be due to other reasons: hemorrhoids, anal fissures, intestinal polyps, peptic ulcers, ulcerative colitis, Crohn’s disease, the use of non-steroidal anti-inflammatory drugs, etc.
The test results are not affected by substances present in food, therefore, a special diet does not need to be followed to prepare for the study.

The purpose of the test is to diagnose inflammatory diseases of the gastrointestinal tract.
Indications for appointment:
– diagnosis of suspected inflammatory bowel diseases such as ulcerative colitis, Crohn’s disease, etc.
– control of inflammatory bowel diseases
– differential diagnosis between organic inflammatory diseases and functional irritable bowel syndrome
Definition of this a biomarker in feces is a good screening test before endoscopic examination for suspected irritable bowel syndrome.This is especially important for children.

Microscopic examination gives a picture of all parasites and pathogens that are in the test material (in the feces) at the time of collection. Diagnosis of most intestinal parasites is based on the detection of protozoa and their cysts, eggs or helminth larvae.

Enterobiasis is widespread, with the greatest occurrence in childhood from 5 to 10 years.
The route of transmission is fecal-oral.
With feces, eggs are very rarely excreted, therefore, for diagnosis, material is taken with adhesive tape from the skin of the perianal region.Scraping is performed in the morning after waking up, daily for three days. The taken material is placed on a glass slide, the glass with the material is delivered to the laboratory, after which its microscopic examination is carried out.

Analysis of feces for enterobiasis in Moscow

Enterobiasis is an intestinal infection accompanied by perianal itching and intestinal disorders. The causative agent of this disease is pinworm, which belongs to the group of nematodes and settles in the large intestine.

Pinworms are sent to the anus only at the stage when they need to lay eggs. The transmission of the pathogen occurs from a sick person to a healthy one. Egg larvae, fixing themselves on the skin, contribute to the development of inflammation, and adults worsen the work of the intestines.

What the analysis shows

Stool analysis for enterobiasis is the standard method for determining the presence of pinworms in the body. After receiving the result, the doctor can determine:

• Approximately how many worms are in the intestines.
• What cycle do helminths go through at the time of examination.
• How severe is the form of the disease.

Based on the results of the diagnosis, the doctor will be able to prescribe an effective treatment.

Indications for analysis

The reason for the appointment of an analysis is the appearance of symptoms indicating enterobiasis. The analysis of feces is not always informative, since eggs are not deposited in feces, but on the surface of the skin on the eve of the anus.In this case, the eggs of the nematode in the feces will be absent.

The main sign of the presence of pinworms in the body is severe itching in the anal area. In addition, the patient complains about:

• abdominal pain;

90,021 nausea;

• upset stool.

This type of examination is mandatory when a child enters child care facilities, when undergoing medical examinations before starting work.

The chance of finding pinworm eggs in the feces is small, and amounts to fifteen percent, therefore, in order to diagnose enterobiasis, it is scraping that is used.

Preparation for procedure

Before passing the scraping for enterobiasis, preparation is not required. The only conditions are:

• Delivery of scrapings in the morning.
• A swab may be taken until the bowel is emptied.
• Women should not urinate before the scraping is taken.
• Seven days before the examination, you should not take laxatives, antibiotics and drugs used to combat helminthic invasion.

The rules for taking feces for analysis are the same as when examining for other types of helminthic invasions. The material is taken from three different locations. This is done to increase the likelihood of finding eggs. For a full study, two teaspoons of feces are enough. It is undesirable to store a container with feces, but it is allowed to place containers with feces for a period not exceeding eight hours in the refrigerator.

Reasons for false results

The result will be false if the material was taken at a time when the nematodes did not lay eggs. In this case, the pinworms will be in the rectum, but the scraping result will be negative.

Before taking the material, it is impossible to carry out hygienic procedures for the genitals and anus, in which case the eggs may be washed off. The same will happen when you have a bowel movement.

How is the analysis done

The collection of material can be carried out in two ways: on adhesive tape or in a sterile container.Containers suitable for examination are available from pharmacies. They are a sterile container with a sterile cotton swab. With a cotton swab, lightly move it along the skin around the anus. After that, the stick is returned back to the container and tightly closed.

The second method involves the use of a glass slide with adhesive tape, which is carefully torn off the glass and pressed with the adhesive side to the skin of the anus. After that, Lena returns to the glass and signs.The material is ready to be sent to the laboratory. Samples prepared for analysis are viewed under a microscope.

Norms and interpretation of the result

Normally, there should be no pinworm eggs on either a cotton swab or adhesive tape. In the presence of symptoms of helminthic invasion and a negative examination result, scraping for enterobiasis is repeated after a while, and the result is considered false.

When examining feces, eggs of worms belonging to other species are more often found.With PCR, the genetic material of pinworms is extremely rare, but in some cases, the analysis of feces for pinworm eggs is carried out in conjunction with scraping.

If during this time the material is not delivered to the laboratory, the sample result will be false. The larva, after the egg has been laid, takes four hours to hatch. The analysis of feces for enterobiasis is carried out in the case when scraping cannot be carried out. If the skin of the anus is severely combed and covered with sores.

When examining feces, it is not eggs that can be found, but the remains of male pinworms, which die after mating.In rare cases, pinworms themselves can be found in the feces, which are clearly visible due to their mobility.

The result of the analysis is usually sent to the doctor the next day.

With a one-time delivery of a scraping for enterobiasis, the probability of finding eggs is about fifty percent, with a second examination, the probability of detection increases to ninety percent.