What are the key differences between active and latent TB. How is latent TB diagnosed and treated. Why is identifying latent TB important for public health. What are the risk factors for developing active TB from a latent infection.

The Three Stages of Tuberculosis: From Infection to Disease

Tuberculosis (TB) is a unique bacterial infection that typically progresses through three distinct stages. Understanding these stages is crucial for effective prevention, diagnosis, and treatment.

1. Primary TB infection
2. Latent TB infection
3. Active TB disease

Remarkably, millions of people carry latent TB bacteria without ever developing active tuberculosis. In the United States alone, an estimated 13 million individuals have a latent TB infection.

Latent TB Infection: The Hidden Threat

Latent TB infection is a state where the tuberculosis bacteria are present in the body but remain dormant. Approximately 30% of people exposed to Mycobacterium tuberculosis develop latent TB. If left untreated, 5-10% of these individuals may progress to active tuberculosis disease at some point in their lives. This risk is significantly higher for those with HIV.

Who is at Risk for Latent TB Progression?

Certain factors increase the likelihood of latent TB progressing to active disease:

• Recent infection (within the past two years)
• Weakened immune system
• HIV infection
• Advanced age
• Certain medical conditions

Dr. Hayan Yacoub, an internal medicine practitioner at Austin Regional Clinic in Texas, describes latent TB as “a ticking bomb waiting for your immune system to get weak.” This highlights the importance of identifying and treating latent TB to prevent future complications and disease spread.

Primary TB Infection: The Initial Encounter

TB infection begins when a person inhales airborne bacteria, typically through close contact with individuals who have active TB and are coughing or sneezing. The body’s response to this initial infection can vary:

• In many people, the immune system immediately kills the inhaled bacteria.
• In others, white blood cells called macrophages surround the TB bacteria, causing them to enter a dormant state (latent infection).
• In certain populations, such as infants, the elderly, and those with weakened immune systems, symptoms of active tuberculosis may develop within weeks of primary infection.

Diagnosing Latent TB: Silent but Detectable

While individuals with latent TB have no symptoms and are not infectious, their infection can be detected through specific tests:

• Tuberculin skin test
• Interferon-gamma release assay (IGRA) blood test

A positive result on either of these tests indicates exposure to tuberculosis and the presence of a latent infection. This information is crucial for healthcare providers to assess the need for preventive treatment and monitor individuals at risk of developing active TB.

Who Should Be Screened for Latent TB?

In the United States, universal screening for latent TB is not necessary due to the relatively low prevalence of active TB. Dr. Lee Reichman, founding executive director at the Rutgers Global Tuberculosis Institute, explains, “The average person doesn’t get exposed to TB. For example, if you work in publishing and just go to work and go home, we don’t test you because [exposure] is unlikely.”

However, certain high-risk populations should be screened for latent TB:

• Recent immigrants from countries with high TB rates
• Individuals whose work or living situations put them in contact with active TB cases
• People who inject drugs
• Children under 4 and those exposed to high-risk adults
• Individuals with conditions that increase the risk of TB activation (e.g., diabetes, end-stage renal disease, HIV)
• People taking immunosuppressive medications
• Individuals planning to start chemotherapy or long-term steroid treatment

The Importance of Treating Latent TB

Identifying and treating latent TB is crucial for several reasons:

1. Preventing progression to active TB disease
2. Reducing the spread of tuberculosis in communities
3. Avoiding complications in future medical treatments
4. Protecting vulnerable populations

Treatment for latent TB typically involves a course of antibiotics, which can significantly reduce the risk of developing active tuberculosis. The specific regimen may vary depending on individual factors and local guidelines.

Active TB Disease: When Dormancy Ends

Active TB disease occurs when the dormant bacteria in a latent infection become active and begin to multiply. This can happen when the immune system is weakened or compromised. Symptoms of active TB may include:

• Persistent cough (lasting more than three weeks)
• Chest pain
• Coughing up blood or sputum
• Fatigue
• Fever
• Night sweats
• Unintentional weight loss

Active TB is infectious and requires immediate medical attention and treatment to prevent further spread of the disease.

The Global Impact of Tuberculosis

Tuberculosis remains a significant global health concern, particularly in developing countries. Understanding the differences between latent and active TB is crucial for effective disease control and prevention strategies.

TB and HIV: A Dangerous Combination

The risk of a latent TB infection progressing to active disease is substantially higher in people with HIV. This underscores the importance of comprehensive screening and treatment programs for both conditions in high-risk populations.

Challenges in TB Control

Several factors contribute to the ongoing challenge of tuberculosis control worldwide:

• Limited access to healthcare in some regions
• Emergence of drug-resistant TB strains
• Stigma associated with the disease
• Incomplete treatment adherence
• Lack of awareness about latent TB

Addressing these challenges requires a multi-faceted approach involving improved diagnostics, treatment options, and public health initiatives.

Advancements in TB Prevention and Treatment

Ongoing research and development in the field of tuberculosis are yielding promising results:

New Diagnostic Tools

Improved diagnostic techniques are being developed to detect TB more quickly and accurately, even in resource-limited settings. These include:

• Rapid molecular tests
• Advanced imaging technologies
• Novel biomarker-based assays

Innovative Treatment Approaches

Scientists are exploring new treatment strategies to combat TB, including:

• Shorter treatment regimens for both latent and active TB
• Novel drug combinations to address drug-resistant strains
• Immunotherapies to boost the body’s natural defenses against TB

Vaccine Development

While the BCG vaccine has been used for decades to prevent severe forms of TB in children, researchers are working on developing more effective vaccines that could:

• Prevent initial infection
• Stop progression from latent to active TB
• Provide long-lasting immunity across all age groups

The Role of Public Health in TB Control

Effective TB control requires a coordinated public health approach. Key components of successful TB control programs include:

1. Active case finding and contact tracing
2. Directly observed therapy (DOT) to ensure treatment adherence
3. Targeted screening of high-risk populations
4. Education and awareness campaigns
5. Collaboration between healthcare providers, public health agencies, and community organizations

By implementing comprehensive strategies that address both latent and active TB, public health officials can work towards reducing the global burden of tuberculosis.

Living with Latent TB: What You Need to Know

If you’ve been diagnosed with latent TB, it’s essential to understand your condition and take appropriate steps to protect your health:

Follow-up Care

Regular check-ups with your healthcare provider are crucial to monitor your condition and assess the need for treatment. Your doctor may recommend:

• Annual chest X-rays
• Periodic blood tests
• Symptom monitoring

Treatment Options

Depending on your individual risk factors, your doctor may recommend preventive treatment for latent TB. Common treatment regimens include:

• Isoniazid therapy for 6 to 9 months
• Rifampin therapy for 4 months
• Combination therapy with isoniazid and rifapentine for 3 months

It’s crucial to complete the full course of treatment as prescribed to effectively prevent the progression to active TB.

Lifestyle Considerations

While latent TB doesn’t require drastic lifestyle changes, certain habits can help maintain overall health and reduce the risk of TB activation:

• Maintain a balanced diet rich in nutrients
• Exercise regularly to boost immune function
• Avoid smoking and excessive alcohol consumption
• Manage stress through relaxation techniques or counseling
• Get adequate sleep to support immune health

Travel Precautions

If you have latent TB and plan to travel, especially to areas with high TB prevalence, consider these precautions:

• Consult your healthcare provider before your trip
• Carry documentation of your latent TB status and any ongoing treatment
• Be aware of TB symptoms and seek medical attention if they develop
• Consider wearing a mask in high-risk settings

The Future of TB Prevention and Control

As we look to the future, several promising developments offer hope for improved TB prevention and control:

Personalized Medicine Approaches

Advances in genomics and molecular diagnostics are paving the way for more targeted TB treatments. This personalized approach could lead to:

• More effective treatment regimens
• Reduced side effects
• Improved patient outcomes

Digital Health Technologies

The integration of digital technologies in TB care holds great potential:

• Mobile apps for treatment adherence and symptom monitoring
• Telemedicine consultations for remote patient management
• AI-powered diagnostic tools for faster and more accurate TB detection

Global Collaboration and Research

International efforts to combat TB are intensifying, with initiatives focusing on:

• Sharing of data and research findings
• Coordinated funding for TB research and development
• Harmonization of TB control strategies across countries

These collaborative efforts aim to accelerate progress towards global TB elimination goals.

Empowering Individuals in the Fight Against TB

While healthcare providers and researchers play crucial roles in TB control, individuals also have an important part to play:

Education and Awareness

Understanding the basics of TB transmission, symptoms, and prevention can help individuals:

• Recognize potential TB exposure
• Seek timely medical attention
• Support community TB control efforts

Advocacy and Support

Individuals can contribute to TB control by:

• Supporting TB awareness campaigns
• Advocating for increased funding for TB research and control programs
• Participating in community health initiatives

Reducing Stigma

By promoting understanding and compassion, we can help reduce the stigma associated with TB, encouraging:

• Open discussion about TB
• Increased willingness to seek testing and treatment
• Better support for those affected by TB

Through these collective efforts, we can work towards a future where both latent and active TB are effectively managed, ultimately leading to better health outcomes for individuals and communities worldwide.

Latent Tuberculosis Infection vs. Active TB Disease: What’s the Difference?

Tuberculosis (TB) is unlike most bacterial infections in that it usually doesn’t cause symptoms immediately. Even when it starts to make you sick, symptoms come on very gradually and can often be confused with other conditions.

Most commonly, tuberculosis goes through three stages:

• Primary TB infection
• Latent TB infection
• Active TB disease

Millions of people carry latent TB bacteria but never develop active tuberculosis. In fact, it’s estimated that as many as 13 million people in the United States have a latent TB infection. (1,2,3)

About 30 percent of people who get exposed to Mycobacterium tuberculosis will develop latent TB, and if that’s left untreated, around 5 to 10 percent of those people could end up getting active tuberculosis disease at some point in their lifetime. The number is much higher for people infected with HIV. (3,4)

Tuberculosis is more likely to enter the active phase in people who have acquired the infection recently (in the past two years). It’s also more likely to be active among those whose immune systems are weakened.

In some literature, latent tuberculosis may also be referred to as “tuberculosis infection,” while active tuberculosis is also known as “tuberculosis disease,” as noted in a 2021 journal article.

Primary or Initial Tuberculosis Infection

Infection with M. tuberculosis begins when a person breathes in airborne bacteria.

This is more likely to happen if a person is in close contact with one or more people infected with active TB who are coughing or sneezing.

In many people, any inhaled bacteria are killed immediately by the immune system. In others, the TB bacteria are surrounded by macrophages, a type of white blood cell, and enter a dormant state. This is called latent infection, and this stage can last for years or even for life. But in certain populations, including infants, the elderly, those with recently acquired TB infection, and people with weakened immune systems, symptoms of active tuberculosis may start within weeks of primary infection. (2)

What It Means to Have a Latent TB Infection

While a person with latent TB has no symptoms and is not infectious, a tuberculin skin test or blood test for TB — called the interferon-gamma release assay, or IGRA — will be positive, showing that the person has not only been exposed to tuberculosis but has a latent (or “occult”) infection with the bacteria that causes tuberculosis. (2,5)

“You have a ticking bomb waiting for your immune system to get weak,” says Hayan Yacoub, MD, internal medicine practitioner at Austin Regional Clinic in Texas. Latent TB can also complicate treatment for potential health issues that happen later in life, he says. That’s why it’s important to identify and treat latent TB.

If a latent infection is discovered, treatment is recommended in certain individuals at high risk to prevent that person from developing active disease and to prevent the further spread of tuberculosis.

People at high risk of TB infection (such as those who work in hospitals) may be screened, sometimes annually, for latent infection.

Who Should Get Tested for Latent Tuberculosis?

In the United States, there isn’t a need to test everyone for latent TB because it’s unlikely most people will come in contact with someone who has the active disease.

“The average person doesn’t get exposed to TB,” says Lee Reichman, MD, MPH, the founding executive director at the Rutgers Global Tuberculosis Institute in Newark, New Jersey. “For example, if you work in publishing and just go to work and go home, we don’t test you because [exposure] is unlikely.”

Screening for latent TB is done based on your risk factors. The following populations should generally be screened: (6,7)

• People who have recently come to the United States from a country with a high rate of tuberculosis
• People whose work or living arrangement puts them in contact with people who have active tuberculosis
• People who struggle with injected drug use
• Children under age 4 or children and adolescents exposed to adults in high-risk categories
• People with other diseases that increase the risk of developing active TB once infected, such as insulin-requiring diabetes, end-stage renal disease, prior gastrectomy, or HIV infection
• People who are taking drugs that block tumor necrosis factor alpha (TNF-alpha), such as infliximab (Remicade), adalimumab (Humira), or etanercept (Enbrel), as well as those taking steroid medications at higher doses or over a longer period of time

People who plan to start chemotherapy for cancer or an immunosuppressive drug — to treat an autoimmune condition, for example — should also be screened for latent tuberculosis.

The risk of a latent TB infection becoming active is much higher in people infected with HIV than those without HIV. (8)

What Does Treatment for Latent TB Involve?

Treatment for latent TB involves less medication and a shorter regimen than treatment of active TB, says Alexea M. Gaffney-Adams, MD, an internist with subspecialty training in infectious disease at Stony Brook Medicine in Stony Brook, New York.

The CDC and the National Tuberculosis Controllers Association (NTCA) now recommend a short-course of a rifamycin (Aemcolo)-based three- or four-month latent TB infection treatment. The previous recommendation was a six- or nine-month isoniazid (Nydrazid) single-drug therapy. Some of the regimens your infectious disease doctor may recommend are:

• Three months of once-weekly isoniazid plus rifapentine (Priftin), called 3HP
• Four months of daily rifampin (Rifadin), called 4R
• Three months of daily isoniazid plus rifampin, called 3HR (5,9)

What It Means to Have Active Tuberculosis Disease

In active tuberculosis, the bacteria multiply in the body, causing noticeable symptoms. This is also when the disease can spread to others. The difference between active and latent TB is the amount of organisms in the body, according to Dr. Reichman.

The most common kind of tuberculosis, pulmonary tuberculosis, typically causes the following symptoms: (5,10)

• Breathing difficulty
• Chest pain
• Coughing, sometimes with phlegm
• Fatigue
• Fever
• Night sweats
• Weakness
• Weight loss
• Wheezing

In addition to the lungs, tuberculosis can affect other parts of the body, including the lymph nodes, other internal organs, bones and joints, or the brain. This form of the disease, called extrapulmonary tuberculosis, also causes fatigue, fever, night sweats, weakness, and weight loss, and it may also cause other symptoms depending on what body parts are affected.

Active TB is curable, but the disease can be deadly if left untreated. About 45 percent of people not infected with HIV, and almost all HIV-positive people, will die from TB without proper treatment.  (11)

Tuberculosis is spread through the air, which means you can only get it by breathing contaminated air. If someone who is actively sick talks, coughs, sneezes, or speaks, they can spread TB. People with active TB can infect 10 to 15 other people they come into regular close contact with in the course of a year. (11)

The reality is that if someone does have active TB, they’re breathing bacteria out into the air, and anyone can pick them up, says Dr. Gaffney-Adams. “You’re most likely to spread it to your household, but it can definitely spread elsewhere.”

Who Should Get Tested for Active TB Disease?

If you find out you’ve been exposed to someone with TB, you need to be screened, says Gaffney-Adams. If a first screening was negative, she recommends going in for testing again, especially if you experience any respiratory symptoms.

Screening is recommended for anyone with the following symptoms of active TB: (7)

• Coughing that lasts for three weeks or longer
• Weight loss that can’t be explained
• Coughing up blood
• Chest pain
• Loss of appetite
• Night sweats
• Fever
• Fatigue

According to Gaffney-Adams, who has treated several cases of both latent and active TB, night sweats is a very common symptom in active TB disease. It’s usually pretty dramatic, she says, like sweating so heavily that a person needs to get up and change sheets and clothes.

What Does Treatment for Active TB Involve?

The treatment for any type of active tuberculosis is long-term administration of antibiotics.

Because there are so many drug-resistant strains of TB, people with active disease must take more than one antibiotic to ensure that all of the bacteria are killed. In addition, because tuberculosis bacteria grow slowly, it’s necessary to take the antibiotics for four to nine months typically. (5,12)

The two most common regimens for active TB disease, where TB is not drug resistant, are:

• The four-month TB treatment regimen, which consists of a high-dose daily rifapentine (Priftin) with moxifloxacin (Avelox), isoniazid (Nydrazid), and pyrazinamide
• The six- to nine-month RIPE TB treatment regimens, which consist of rifampin (Rifadin), isoniazid (Nydrazid), pyrazinamide, and ethambutol (Myambutol)

One major concern in the treatment of active TB is making sure people continue to take the medication even after symptoms have gone away. People typically need to take medication for many months, so they often get tired of it and forget, says Robert Amler, MD, dean and professor of public health at New York Medical College in Valhalla, New York.

Stopping the drugs early can cause the TB bacteria to return, and that bacteria may not respond to drugs that worked the first time. This is called drug-resistant TB, and it’s much harder to treat.

To make sure people with active TB finish the full medication schedule, directly observed therapy, or DOT, is used. In DOT, a trained healthcare worker provides each dose of medication, watches the patient swallow it, and documents that the medication has been taken.

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Latent and Active Tuberculosis, What Is the Difference

By Dr Tan Seow Yen, Head, Training and Education Office, Infectious Disease Research and Training Office, National Centre for Infectious Diseases

While tuberculosis (TB) and humans have coexisted for thousands of years, the understanding of the pathophysiology of TB continues to evolve. While the classical model of distinct latent and active forms of TB disease are well known to most, it is increasingly understood that the complex bacterial and host dynamics result in the pathology of TB disease falling on a spectrum.¹

Nonetheless, the notion that certain cases of untreated latent TB can progress to active TB still holds true. Overall, without treatment, about 5% to 10% of infected persons will develop TB disease at some time in their lives.² About half of those people who develop TB will do so within the first two years of infection. For persons whose immune systems are weak, especially those with untreated human immunodeficiency virus (HIV) infection, the risk of developing TB disease is considerably higher than for persons with normal immune systems. When the TB bacteria overcome the defences of the immune system and begin to multiply, it results in the progression from latent TB to active TB. Some people develop active disease soon after infection, while others progress to active disease later when their immune system becomes weak.

There are considerable differences between the two conditions. In terms of symptoms, persons with latent TB do not feel sick and do not have any symptoms, while most persons with active TB experience symptoms, which generally include unexplained weight loss, loss of appetite, night sweats, fever, fatigue and chills. Depending on site of infection, the symptoms experienced by the person could vary, such as prolonged cough, or coughing up blood in persons with pulmonary TB; and back pain in persons with spinal TB.

Persons with latent TB infection are not infectious and cannot spread TB infection to others. However, for active TB, only infections of the lungs and larynx (voice box) is contagious and capable of spread to others.

A latent TB infection is often diagnosed in an asymptomatic individual, who has either a skin test or blood test result indicating infection. It is normal that the chest X-ray would not show indication of infection, and the sputum tests for TB are expected to be negative. In short, aside from the positive blood or skin test, there are no symptoms and signs of active disease. The diagnosis of active TB is made, when there are symptoms and signs of active disease, and a positive test results which can be a sputum sample showing growth of the bacteria, or a positive nucleic acid amplification test.

There are treatments available for both active and latent TB, although the treatment regimen used are slightly different. Treatment of latent TB aims to prevent the progression to active TB, and usually involves a single drug, taken for a duration of a few months. Treatment for active TB is generally more intense, requiring the use of multiple drugs (mostly consisting of four drugs), and the treatment course is generally longer.

References
1 Tuberculosis, Jennifer Furin et al, Lancet 2019; 393: 1642–56

2 https://www.cdc.gov/tb/publications/factsheets/general/ltbiandactivetb.htm

The article was also published in Volume 1 of Infectious Disease Intelligence here.

How to Diagnose TB – Tips from a TB Doctor

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How to Diagnose TB : Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis. Primary diagnosis of tuberculosis will require an X-ray of the lungs and a subsequent consultation with a phthisiatrician. As an additional examination, the doctor may prescribe a CT scan of the lungs, ultrasound, blood and sputum tests, and a biopsy.

Which doctor treats tuberculosis : If you have symptoms of tuberculosis, you should first consult a TB doctor.

Tuberculosis is a bacterial infection that is spread through the air when an infected person coughs or sneezes. It mainly affects the lungs, but can affect any part of the body, including the abdomen, glands, bones, and nervous system.

Causes of tuberculosis

Tuberculosis affecting the lungs is the most contagious type, but it usually spreads only after prolonged contact with the sick. In most healthy people, the body’s natural defense against infection and disease kills the bacteria and the disease does not develop, or prevents it from spreading in the body. If the immune system fails to kill or contain the infection, it can spread to the lungs or other parts of the body, and symptomatic active TB develops. In some cases, the bacteria infect the body but cause no symptoms—this is called latent TB. Up to 10% of people with latent TB eventually develop active disease several years after initial infection. Although tuberculosis is transmitted in the same way as a cold or flu, it is not as contagious. A person will have to spend long periods (several hours) in close contact with an infected person in order to contract the infection themselves. For example, tuberculosis is usually transmitted between family members living in the same household. Not all TB patients are contagious – patients with extrapulmonary disease do not spread the infection and are not dangerous to others.

TB risk groups

Anyone can get TB, but the people most at risk are:

• who live in, travel to, or spend time in a country or area with a high incidence of TB;
• in prolonged close contact with an infected person;
• with a condition that weakens the immune system, such as diabetes, HIV infection;
• undergoing treatment that weakens the immune system, such as chemotherapy; very young or old;
• in poor health or poor nutrition;
• alcohol or drug abusers
• was in prison.

HIV and tuberculosis

Patients living with HIV are at higher risk of infection and death from tuberculosis. Latent tuberculosis, if left untreated, is more likely to become active in an HIV patient. The following steps are recommended for HIV patients to reduce their risk of contracting TB infection:

• periodic examinations for tuberculosis
• HIV therapy as recommended by healthcare professionals
• avoid contact with tuberculosis patients
• smoking cessation
• a balanced diet rich in nutrients. Helps reduce the risk of HIV complications and improve drug absorption
• regular exercise to promote immune system health.

Symptoms of pulmonary tuberculosis

The symptoms of tuberculosis vary depending on which area of ​​the body is affected. The disease usually develops slowly, and it may take several weeks before the patient notices any symptoms. Sometimes they may not appear until months or even years after the initial infection.

General symptoms of tuberculosis

• lack of appetite and weight loss;
• high temperature;
• night sweats;
• extreme tiredness or fatigue.

However, these signs can have many different causes and are not always a sign of TB.

Pulmonary tuberculosis

Most cases of tuberculosis affect the lungs, which can cause:

• persistent cough lasting more than 3 weeks, usually with sputum, which may be bloody;
• shortness of breath that gradually worsens.

Extrapulmonary tuberculosis

Less commonly, tuberculosis infections develop in areas outside the lungs, such as the lymph nodes, bones and joints, the digestive system, bladder and reproductive system, and the brain and nervous system. Symptoms may include:

• permanently inflamed, swollen and painful glands;
• abdominal pain;
• pain and loss of motion in the affected bone or joint;
• persistent headache;
• convulsions.

Tuberculosis Diagnosis

Several tests are used to diagnose tuberculosis, depending on the type of disease suspected.

Pulmonary tuberculosis

Diagnosis of pulmonary tuberculosis can be difficult and usually requires several tests. The patient may have a chest x-ray or CT scan of the lungs to look for changes in the appearance of the lungs that indicate tuberculosis, and sputum samples will be taken to examine it for the presence of the infectious agent. These tests are important for choosing the most effective treatment for the patient.

Extrapulmonary TB

Several tests can be used to confirm extrapulmonary TB, which include:

• CT, MRI, or ultrasound of the affected body part;
• endoscopic research methods – fibrogastroduodenoscopy, laparoscopy;
• urine and blood tests;
• biopsy – a small sample of tissue or fluid is taken from the affected area and examined for the presence of mycobacteria;
• A lumbar puncture in which a small sample of cerebrospinal fluid is taken from the base of the spine and examined for spread of bacteria to the nervous system.

Testing for latent TB

In some cases, a person may need to be tested for latent TB, for example if they have been in close contact with someone who has been diagnosed with active pulmonary disease, or if they have recently was in a country with a high rate of tuberculosis. The Mantoux test is a widely used test for latent tuberculosis. It involves injecting a small amount of a substance called tuberculin into the skin of the forearm. It is also called tuberculin skin test (TST). If the patient has a latent TB infection, the skin will be sensitive to tuberculin and a hard, red bump will appear at the injection site, usually within 48 to 72 hours of the test. If a person has a very severe skin reaction, they will need a chest x-ray to confirm active TB. If he does not have a latent infection, the skin will not respond to the Mantoux test. However, since TB can take a long time to develop, you may need to be retested at a later stage. If a patient has been vaccinated with BCG, they may have a mild skin reaction to the Mantoux test, and this does not necessarily mean that they have latent TB.

Interferon-gamma release assay

Interferon-gamma release assay (IGRA) is a blood test for tuberculosis that is becoming increasingly available. It can be used to diagnose latent tuberculosis:

• if the patient has a positive Mantoux test;
• if he has previously been vaccinated with BCG – the Mantoux test may be unreliable in these cases;
• as part of a TB screening if they have just arrived from a country where TB is common;
• if the patient is about to undergo a course of treatment that will suppress their immune system; if he is a medical professional.

Tuberculosis treatment

Although tuberculosis is a serious disease that can be fatal if left untreated, death during treatment is extremely rare. TB treatment usually involves taking antibiotics for several months, and most patients do not need to be hospitalized for this.

Pulmonary TB

A patient with active pulmonary TB will be given at least 6 months of a combination of antibiotics. Common regimens include:

• 2 antibiotics (isoniazid and rifampicin) for 6 months;
• 2 additional antibiotics (pyrazinamide and ethambutol) for the first 2 months of a 6-month treatment period.

It may take several weeks before the patient feels better. The exact time will depend on your general health and the severity of your TB. After 2 weeks of taking antibiotics, most patients cease to be contagious and report a positive trend. However, it is important to continue taking the medication exactly as prescribed and complete the entire course of antibiotic therapy. If antibiotics are stopped before the course is completed or a dose is missed, the TB infection can become resistant to antibiotics. This is potentially dangerous because it will require a more aggressive, prolonged and possibly more toxic treatment.

Treatment of extrapulmonary TB

Extrapulmonary TB can be treated with the same combination of antibiotics as the pulmonary form. If the patient has TB in areas such as the brain or the pericardium, they may first be given a corticosteroid (prednisolone) for several weeks along with antibiotics. This will help reduce swelling in the affected areas. As with pulmonary TB, it is important to take your medicines exactly as prescribed and complete the entire course of treatment.

Treatment of multidrug-resistant TB

Although rare today, there are strains of TB that are resistant to 2 or more antibiotics. This is known as multidrug resistant tuberculosis. It requires a much longer course of antibiotic treatment – from 9 to 24 months depending on the form. Multidrug-resistant tuberculosis usually has less favorable outcomes than the classic form of the disease.

Treatment of latent TB

If a patient is diagnosed with latent TB at 65 years of age or younger, treatment is usually recommended. However, antibiotics used to treat tuberculosis can cause liver damage in older people, so individual tactics are used for each patient. In some cases, testing and treatment for latent TB may be recommended for patients who require treatment that weakens their immune system, such as long-term steroid drugs, chemotherapy, or biological inhibitors. Treatment for latent TB usually includes:

• or a combination of rifampicin and isoniazid for 3 months;
• or isoniazid alone for 6 months.

Latent TB is not treated if it is thought to be resistant to drugs. In this case, the patient can be observed regularly to make sure that the infection does not reactivate.

Side effects of treatment

Isoniazid can cause nerve damage (peripheral neuropathy). Therefore, vitamin B6 (pyridoxine) supplements are given to patients undergoing TB treatment to reduce this risk. In rare cases, antibiotics can cause serious eye damage. Rifampicin may reduce the effectiveness of some types of contraception, such as combined birth control pills, so an alternative method of contraception should be used while taking rifampicin.

TB vaccination

The BCG vaccine provides protection against TB and is recommended by the World Health Organization for infants, children, and adults under 35 who are considered at risk of contracting TB. The BCG vaccine is not usually given to people over 35 because there is no evidence that it works for people in this age group. The risk groups include:

• children living in areas with a high incidence of tuberculosis; people with close relatives from countries with a high incidence of tuberculosis;
• people who are going to live and work with the local population for more than 3 months in an area with a high incidence of tuberculosis.

If the person is a healthcare worker and has contact with patients or clinical specimens, they should also be vaccinated against tuberculosis, regardless of age, if: they have not been previously vaccinated and the Mantoux skin test or blood test for interferon gamma isolation is negative.

Tuberculosis prevention

Usually a TB patient does not need to isolate during treatment, but it is important to take some basic precautions to stop the infection from spreading to family and friends. The patient should:

• stay away from work, school, until he ceases to be contagious to others;
• Always cover your mouth when coughing, sneezing or laughing;
• Dispose of used wipes carefully in a sealed plastic bag;
• open windows whenever possible to allow fresh air to flow in the places where he spends his time; do not sleep in the same room with other people.

Author: Telegina Natalya Dmitrievna

Specialization: Therapist

Where does the reception: MRI center and clinic RIORIT

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The best specialists in St.

Petersburg with a rating of 4.5+

Ananiev Semyon Mikhailovich

Specialization: Phthisiatrician

Medical experience: since 2010

Where does the reception: Clinic Scandinavia

Kulakova Natalya Valerievna

Specialization: Phthisiatrician

Medical experience: since 1998

Place of appointment: German Family Clinic, Clinic Scandinavia

Literature

1. Borisov S.E. Diagnosis of tuberculosis: possibilities and limits // In: Tuberculosis today: problems and prospects. M. – 2000 – p. 92-97.
2. Cardona PJ. Reactivation or reinfection in adult tuberculosis: Is that the question? Int J Mycobacteriol. 2016 Dec;5(4):400-407. doi: 10.1016/j.ijmyco.2016.09.017. Epub 2016 Oct 27. PMID: 27931680.
3. Gunzburg A.JI. Genodiagnostics of infectious diseases // Zhurn. microbiol., epidemiol. and immunobiol. -1998. No. 3. – p. 8695.
4. Litvinov V.I., Gergert V.Ya., Moroz A.M. Immunology of tuberculosis // Bulletin of the Russian Academy of Medical Sciences. 1999. – No. 7. – p. 8-11.
5. Koch A, Mizrahi V. Mycobacterium tuberculosis. Trends Microbiol. 2018 Jun;26(6):555-556. doi: 10.1016/j.tim.2018.02.012. Epub 2018 Mar 23. PMID: 29580884.
6. Son I.M. Tuberculosis incidence // Abstract collection “Tuberculosis”. 1997. – No. 6. – p. 1-14.
7. Chernousova JI.H., Larionova E.E., Sevastyanova E.V. The role of PCR analysis in complex bacteriological studies in phthisiology // Problems of tuberculosis. 2001. – No. 3. – p. 58-60.
8. Cardona PJ. Pathogenesis of tuberculosis and other mycobacteriosis. Enferm Infecc Microbiol Clin (Engl Ed). 2018 Jan;36(1):38-46. English, Spanish. doi: 10.1016/j.eimc.2017.10.015. Epub 2017 Dec 2. PMID: 29198784.

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Latent TB or latent TB is when a person is infected with TB but has no symptoms of active disease. In the article, you will learn how to identify latent tuberculosis, what symptoms may appear and how to treat it.

Tuberculosis is an infectious disease caused by a specific bacterium, Mycobacterium tuberculosis. It is often associated with a characteristic cough and weight loss, but there is a form of TB that is rarely talked about: latent TB. This is when a person is infected with M. tuberculosis, but the bacteria are not active and therefore do not cause symptoms of the disease.

In this article, we look at the symptoms of latent TB, ways to accurately diagnose it, and effective treatments that can help prevent its reactivation.

Definition of latent TB

Latent TB is a form of the disease when TB bacteria are present in the body but do not cause active disease. According to WHO, more than 1/3 of the world’s population are carriers of a latent form of tuberculosis.

This form of TB can last for many years without obvious symptoms, but it can become active at any time. Latent tuberculosis is dangerous, since it is impossible to immediately determine the presence of the disease.

The presence of latent tuberculosis can be determined using special tests, such as Mantoux or GAME. They help to detect the presence of antibodies to tuberculosis bacteria in the blood or changes in the composition of the blood. In case of a positive result, it is necessary to undergo an additional medical examination and start preventive treatment.

Differences between latent and active tuberculosis

Latent tuberculosis and active tuberculosis are two different forms of the disease caused by the bacterium Mycobacterium tuberculosis. Latent tuberculosis means there is an infection but no visible symptoms, usually the presence of bacteria in the body does not cause tissue destruction.

Another important difference between the two forms is that latent TB is not contagious, while the active form can be spread from person to person through coughing, sneezing and talking.

Thus, the control of latent TB is an important step in continuing to control the disease as a whole and prevent the progression of the disease into an active form.

Modes of transmission of latent TB

Latent TB is an asymptomatic form of disease that may go unnoticed in a patient for a long time. But at the same time, this disease is contagious and can be transmitted from person to person.

The main mode of transmission of latent tuberculosis is airborne. That is, the disease can be transmitted through coughing, sneezing and talking of a sick person. Mycobacterium tuberculosis, getting into the air, can be in it for a long time, remaining infectious.

A high risk of getting latent tuberculosis exists in people living in conditions where there is a high population density and sanitary standards are violated. These conditions include prisons, refugees, the homeless, and so on.

Finally, the risk of contracting TB increases in people with weakened immune systems, such as HIV-infected people, cancer patients, chronically ill people, etc.

In general, to protect against latent tuberculosis, it is very important to observe the rules of personal hygiene, treat sick people with care and take the necessary measures to treat the disease in time.

Risks of latent TB

Latent TB occurs when the bacteria that causes TB is in the body but does not show up. However, the presence of latent tuberculosis must be taken seriously, because it can turn into an active form, which causes serious complications.

The risk of developing latent tuberculosis is increased in the following cases:

• contact with a patient with tuberculosis
• weak immunity
• obesity
• alcohol abuse and smoking
• diabetes mellitus 900 26

It is important to remember that the risk of latent tuberculosis is not only in people living in conditions of low hygiene or poor ecology. It can occur in anyone, and therefore it is important to follow preventive measures and undergo regular examinations, especially if you have risk factors.

Symptoms of latent tuberculosis

Latent tuberculosis is a form of tuberculosis that does not show obvious symptoms. In this case, the person is infected with the bacteria but does not have tuberculosis and may not even be aware of the infection in their body.

Often, latent TB is discovered incidentally during examination for other diseases. However, in some cases, symptoms may still appear.

1. Excessive fatigue and weakness
2. If you have a strong rush to lose weight
3. If you have frequent colds
4. If you have a fever

If any symptoms are detected after detecting latent tuberculosis, you should immediately consult a doctor and undergo treatment.

Diagnosis of latent tuberculosis

Latent tuberculosis is a form of the disease in which the causative agent of tuberculosis is in the body, but does not actively develop. This form of the disease is often asymptomatic, but can lead to the development of an open form of tuberculosis in the future.

Also, the diagnosis of latent tuberculosis can be carried out using a blood test for antibodies to the causative agent of the disease. This method is less accurate than the Mantoux skin test, but may be useful if the Mantoux test fails or if the patient is unable to do the skin test for some reason.

In case of a positive diagnosis of latent tuberculosis, it is necessary to consult a phthisiatrician to prescribe effective treatment and prevent the development of an open form of tuberculosis.

How to prevent active TB from latent

Latent TB is a form of the disease in which a person does not show symptoms but has TB bacteria in their body. This condition can last for many years and, if the immune system is disturbed, can be activated in the form of active tuberculosis.

In order to prevent the development of active tuberculosis from latent it is necessary: ​​

• Get tested – if you are at risk for possible infection with tuberculosis, you need to get tested regularly. In case of detection of latent tuberculosis, immediately start treatment.
• Adhere to treatment – Treatment of latent TB involves taking tuberculinostatic drugs for several months. It is necessary to strictly follow the recommendations of the doctor and go through the entire course of treatment to the end.
• Maintain a healthy lifestyle – strengthen your immunity as much as possible, follow the correct daily routine, eat right, do not abuse alcohol and smoking.

Following these steps will help prevent latent active TB from developing and keep you healthy.

Effective treatment of latent TB

Treatment of latent TB involves the use of antibiotics to help prevent active disease. The course of antibiotics lasts from 3 to 9 months, depending on the individual characteristics of the patient and the nature of the disease.

Among the most effective drugs for the treatment of latent tuberculosis are Isoniazid, Rifampicin and Pyrosinamide. They allow you to destroy bacteria that are dormant in the patient’s body.

Proper treatment of latent TB reduces the chance of developing an active form of the disease by up to 90%. After completing a course of antibiotics, it is recommended to undergo a regular medical examination to monitor your health.

• Antibacterial drugs are the main treatment for latent TB;
• The course of treatment can last up to 9 months;
• Isoniazid, Rifampicin and Pyrosinamide are effective drugs;
• Treatment reduces the chance of developing active disease by up to 90%;
• Regular medical examination helps to control the state of health after the end of the course of treatment.

Anti-tuberculosis therapy

Latent tuberculosis is a serious disease that requires mandatory treatment. Anti-tuberculosis therapy is a complex of medications that help fight infection and prevent the development of the disease into an active form.

Drugs used in anti-tuberculosis therapy aim to inhibit the growth and reproduction of M. tuberculosis bacteria that cause disease. They include isoniazid, rifampicin, pyrazinamide, and ethiambutol. As a rule, the course of anti-tuberculosis therapy lasts at least 6 months.

When selecting anti-tuberculosis drugs, the doctor considers many factors, including the age and general condition of the patient, as well as laboratory data to determine the sensitivity of bacteria to drugs. The use of anti-tuberculosis drugs has its own side effects, so the doctor must constantly monitor the patient’s condition during treatment.

Successful completion of anti-tuberculosis therapy leads to elimination of the infection and prevention of the development of the disease into an active form. Although treatment may take several months, adherence to treatment is key to fighting latent TB and preventing the development of complex forms of the disease that can be dangerous to the health of the patient and those around him.

Diet in the treatment of latent TB

Proper nutrition is an important component of the treatment of latent TB. Patients should monitor their diet in order to improve the functioning of the immune system.

First, to strengthen the immune system, it is necessary to increase the amount of protein in the diet. Especially useful food rich in amino acids. These foods include meat, fish, eggs, legumes, and nuts.

Second, patients should increase their intake of fruits and vegetables, as these foods are loaded with vitamins and antioxidants that boost the immune system and help fight infection.

Also pay attention to the consumption of foods rich in calcium, such as dairy products and green vegetables. This is because TB often causes a mineral imbalance that can lead to a weakened immune system.

However, you should not get carried away with fatty foods and easily digestible carbohydrates, such as sweets, cookies and pastries. It is also not recommended to drink strong coffee and alcohol.

In general, the diet for treatment of latent TB should be balanced and varied. The above foods should form the basis of the patient’s diet, but it is also worth watching the portion sizes and not overeating.

Physical exercise to improve health

Patients with latent TB may benefit from physical activity. However, before starting classes, you should consult with your doctor and choose exercises that will not affect the general condition of the body.

The following exercises may be helpful:

• Walking outdoors. Walking improves blood circulation and helps boost immunity;
• Bicycle or step machine. This is a great way to strengthen the cardiovascular system;
• Easy rope exercises. Jump rope helps to strengthen muscles and increase endurance;
• Yoga or Pilates. These exercises help improve flexibility, strength and coordination;

However, it should be remembered that patients with latent TB should avoid strenuous exercise, especially in the early stages of treatment. Exercise should be moderate and performed regularly so that the body can adapt and strengthen itself.

Preventive measures for latent tuberculosis

Latent tuberculosis is a dangerous disease that can become active in the future. In order to prevent its development, it is necessary to take a number of preventive measures.

The first thing to do is to have regular medical check-ups. Even if you don’t have symptoms of TB, regular check-ups can help identify latent disease and start treatment on time.
The second important step in the prevention of latent TB is respiratory hygiene. Contact with TB patients should be avoided, rooms should be regularly ventilated and masks should be used when necessary.
Prolonged contact with patients is one of the main causes of tuberculosis infection. Therefore, if you have any doubts about your health, it is recommended that you quit your job until you have completed a full medical examination.
Finally, it is very important to eat right and pay attention to physical activity. A strong body is better protected from infections, so do not forget about a healthy lifestyle and proper nutrition.

What you need to know about TB vaccination

What is TB vaccination?

Vaccination against tuberculosis is a procedure that allows you to protect the body from the disease and its complications. This is one of the most effective preventive measures against tuberculosis.

Vaccination is given once and must be done in childhood. Vaccination is performed by a simple injection of the vaccine intradermally on the left arm, which allows you to create immunity that lasts for life.

What types of tuberculosis vaccines are available?

There are two types of tuberculosis vaccines:

• BCG-1 is the first vaccine that was created in 1921. It contains a weakened strain of Mycobacterium bovis and is considered the classic TB vaccine.
• BCG-2 is an improved version of the first vaccine. It contains a more attenuated strain and has a lower risk of side effects.

Depending on the country and region, one or the other vaccine may be used.

Who should not be vaccinated against tuberculosis?

Tuberculosis vaccination is not recommended for people who have contraindications:

• High fever and other acute illnesses.
• Weak immune system due to chronic diseases, medications and other causes.
• Pregnant and breastfeeding women.
• Children under two months old and people over 60 years of age.

What side effects can occur after vaccination against tuberculosis?

The following side effects may occur after vaccination against tuberculosis:

• Redness, swelling and itching at the injection site.
• Body temperature up to 38 degrees.
• Increased sweating, headache, weakness.

In most cases, the symptoms resolve quickly and without complications. In case of any complications associated with vaccination, you should consult a doctor.

Complementary treatments for latent TB

In addition to standard treatment, there are additional techniques that can help fight latent TB.

• Immunomodulators. These drugs can help boost the immune system and help the body fight infection more effectively.
• Physiotherapy. Some types of physical therapy can help reduce inflammation and cough, as well as slow the progression of the disease.
• Prophylactic drugs. In some cases, a doctor may recommend taking small doses of antibiotics to prevent reinfection or worsening of the disease.

It is important to understand that these techniques should only be used with a doctor’s prescription and in conjunction with standard care. You should not try to treat latent tuberculosis on your own, as this form of the disease can become active at any time and lead to serious complications. Regular examinations and adherence to the doctor’s recommendations will help to overcome latent tuberculosis faster and more effectively.

Complications and consequences of latent tuberculosis

Although latent tuberculosis does not show characteristic symptoms, it can lead to serious complications and consequences, especially if not treated promptly.

One of the main risks in latent tuberculosis is the transition of the disease into an active form, which can cause inflammation in the lungs, where the main vital organs of the respiratory system are located. This can lead to chronic persistent coughing, bleeding from the lungs, and even death.

In addition, latent TB can increase the risk of contracting HIV, a virus that attacks a person’s immune system, making them more vulnerable to diseases such as TB. This is especially dangerous for those who live in areas with high rates of TB infection or who work with people with open TB.

Other complications may include damage to other organs such as joints, kidneys, or heart. Some patients may also suffer from neurological disorders such as migraines or chronic headaches.

In general, latent TB should not be ignored and symptoms, if present, should be identified as soon as possible. Treatment can help prevent the development of complications and consequences that can be dangerous to a person’s health and life.

Living with latent TB

How to live with latent TB

Living with latent TB can be quite ordinary. However, it is important to monitor your health and visit a doctor to avoid developing an active form of the disease.

Vaccination

There is a vaccine for tuberculosis called BCG. It does not prevent latent TB, but it may reduce the risk of developing active disease. As a rule, BCG is given to infants in the first days of their life.

Healthy lifestyle

It is important to maintain a healthy lifestyle in order to have a strong immune system and prevent the development of active TB. This includes a healthy diet, regular physical activity, and a no-smoking habit.

Social responsibility

It is important to take care not only of your own health, but also of the health of those around you. If you know you have latent TB, avoid contact with immunocompromised people and wear a mask in public.

Risks of latent TB

Latent TB can go unnoticed for a long time, but any change in health should be discussed with a doctor. Although latent TB rarely leads to active disease, immunosuppressed people are at greater risk.

Main risk groups: What precautions should be taken:

Conclusions

Latent tuberculosis is a latent form of the disease that does not manifest itself in obvious symptoms and can last for many years. Also, this form of tuberculosis may not be noticed by standard diagnostic methods, such as x-rays and blood tests.

However, there are a number of diagnostic methods that can be used to detect latent TB, including the mantoux test and a blood test for interferon gamma.

Treatment of latent TB involves taking special drugs for several months. It is also important to monitor your health and detect the disease at an early stage in order to avoid the development of active tuberculosis, which can lead to serious complications and even death.

In general, latent TB is not a problem-free disease, but it can be successfully treated and more dangerous forms of TB can be prevented. It is important to take care of your health and follow all the doctor’s recommendations for successful treatment and prevention of tuberculosis.

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Q&A:

What is latent tuberculosis?

Latent tuberculosis is a condition in which a person is infected with a bacterium, but it does not show up as an active form of the disease. The patient has no symptoms and does not transmit the infection to others.

What symptoms can latent tuberculosis cause?

Latent tuberculosis has no characteristic symptoms, but in some cases there may be mild signs of ill health such as weakness, loss of appetite and slight coughing.

How is latent tuberculosis diagnosed?

To diagnose latent TB, a Mantoux skin test and/or a blood test to check for antibodies to the TB bacteria is required. If the results are positive, then the person should be observed by a doctor and regular examinations should be carried out.

What are the treatments for latent TB?

Latent tuberculosis is treated with antibiotics such as isoniazid. The course of treatment is usually from 3 to 9 months and is an effective means of preventing the active form of the disease.

Can latent tuberculosis be completely cured and is there a risk of recurrence?

Treatment of latent TB is considered effective in preventing the development of active disease.