What are the symptoms of Type A influenza. How long does Type A flu typically last. What treatments are available for Type A flu. How can you prevent catching and spreading Type A influenza.

Understanding Type A Influenza: A Comprehensive Overview

Type A influenza is a highly contagious viral infection that targets the respiratory system. It’s one of three main groups of influenza viruses (A, B, and C) that affect humans, and it’s known for causing widespread outbreaks and potentially severe illness. Unlike its counterparts, Type A influenza has the ability to infect both humans and animals, making it particularly concerning from a public health perspective.

Type A viruses are further categorized into subtypes and strains, and they have a remarkable ability to mutate rapidly. This characteristic not only makes Type A flu more challenging to control but also increases its potential to cause pandemics. The natural hosts for Type A viruses are wild birds, which is why it’s sometimes referred to as avian flu or bird flu.

Why is Type A Influenza Considered More Dangerous?

Type A influenza is often regarded as more dangerous than other types for several reasons:

• Rapid mutation rate: This allows the virus to evade human immune responses and potentially render previous vaccinations less effective.
• Ability to infect multiple species: This increases the risk of viral reassortment and the emergence of novel strains.
• Potential for severe complications: In some cases, Type A flu can lead to life-threatening conditions, especially in high-risk groups.
• Pandemic potential: Due to its characteristics, Type A influenza has been responsible for several global pandemics throughout history.

Recognizing the Symptoms of Type A Influenza

Type A influenza typically presents with a sudden onset of symptoms, distinguishing it from the common cold. Recognizing these symptoms early can lead to prompt treatment and better outcomes. The most common signs of Type A flu include:

• Fever (usually high)
• Severe body aches
• Extreme fatigue
• Dry cough
• Sore throat
• Runny or stuffy nose
• Headache
• Chills

It’s important to note that not everyone with flu will experience all of these symptoms, and the severity can vary from person to person. Some individuals, particularly children, may also experience gastrointestinal symptoms such as nausea, vomiting, and diarrhea.

How Quickly Do Type A Flu Symptoms Develop?

The incubation period for Type A influenza is typically 1-4 days, with an average of 2 days. This means that symptoms usually appear within 48 hours of exposure to the virus. The rapid onset of symptoms is a hallmark of influenza, often catching people off guard with its intensity.

Duration and Progression of Type A Influenza

Understanding the typical duration and progression of Type A flu can help individuals manage their expectations and seek appropriate care. While the course of illness can vary, there are some general patterns to be aware of:

How Long Does Type A Flu Usually Last?

For most healthy adults, Type A flu symptoms typically last about 5-7 days. However, some symptoms, particularly fatigue, can persist for several weeks. The illness usually follows this general timeline:

1. Days 1-3: Sudden onset of symptoms, often with high fever and severe body aches
2. Days 4-5: Peak of symptoms, after which fever typically begins to subside
3. Days 5-7: Gradual improvement of symptoms, though fatigue may persist
4. Days 7+: Most symptoms resolve, but full recovery may take 1-2 weeks

Can Type A Flu Last Longer in Some Cases?

Yes, in some cases, Type A flu can last longer than the typical 5-7 days. Factors that can contribute to a prolonged illness include:

• Age: Older adults and young children may take longer to recover
• Overall health: Those with weakened immune systems or chronic conditions may experience a longer duration of illness
• Complications: Secondary infections or other complications can extend the course of the flu
• Strain virulence: Some strains of Type A influenza may cause more severe or prolonged illness

Potential Complications of Type A Influenza

While many people recover from Type A flu without significant issues, it can lead to serious complications, especially in high-risk groups. Understanding these potential complications is crucial for recognizing when to seek immediate medical attention.

What Are the Most Common Complications of Type A Flu?

The most frequent complications associated with Type A influenza include:

• Pneumonia: This can be viral pneumonia caused by the flu virus itself or secondary bacterial pneumonia
• Myocarditis: Inflammation of the heart muscle
• Encephalitis: Inflammation of the brain
• Myositis: Inflammation of muscle tissues
• Rhabdomyolysis: A severe form of myositis that can lead to kidney damage
• Multi-organ failure: In severe cases, the flu can cause multiple organs to fail

These complications can be life-threatening and require immediate medical intervention. Certain groups are at higher risk for developing complications, including older adults, young children, pregnant women, and individuals with chronic health conditions or weakened immune systems.

Diagnosis and Treatment of Type A Influenza

Accurate diagnosis and timely treatment are crucial in managing Type A influenza and preventing complications. While mild cases may resolve on their own with rest and supportive care, more severe cases or those in high-risk individuals often require medical intervention.

How is Type A Flu Diagnosed?

Diagnosis of Type A influenza typically involves a combination of clinical assessment and laboratory testing:

• Clinical evaluation: A healthcare provider will assess symptoms and medical history
• Rapid influenza diagnostic tests (RIDTs): These can provide results within 10-15 minutes but may not be as accurate as other tests
• Rapid molecular assays: More accurate than RIDTs, these tests can detect viral RNA within 15-30 minutes
• RT-PCR tests: The most accurate but takes longer to get results (1-8 hours)
• Viral culture: Used less frequently due to longer turnaround time (3-10 days)

What Treatments Are Available for Type A Flu?

Treatment for Type A influenza focuses on managing symptoms and preventing complications. The primary approaches include:

1. Antiviral medications:
   • Oseltamivir (Tamiflu)
   • Zanamivir (Relenza)
   • Peramivir (Rapivab)
   • Baloxavir marboxil (Xofluza)

   These drugs can shorten the duration of illness and reduce the risk of complications if started early (within 48 hours of symptom onset).

2. Supportive care:
   • Rest
   • Increased fluid intake
   • Over-the-counter pain relievers and fever reducers
   • Humidifiers to ease respiratory symptoms
3. Treatment of complications: This may involve antibiotics for secondary bacterial infections or more intensive care for severe complications.

Prevention Strategies for Type A Influenza

Preventing the spread of Type A influenza is a crucial public health goal. While complete prevention isn’t always possible, there are several effective strategies to reduce the risk of infection and transmission.

How Can You Protect Yourself from Type A Flu?

The most effective prevention strategies include:

1. Annual vaccination: This is the single most important step in preventing flu. The vaccine is updated each year to protect against the most likely circulating strains.
2. Good hygiene practices:
   • Frequent handwashing with soap and water
   • Using alcohol-based hand sanitizers when soap and water aren’t available
   • Avoiding touching your face, especially your mouth, nose, and eyes
3. Healthy lifestyle habits:
   • Maintaining a balanced diet
   • Getting regular exercise
   • Ensuring adequate sleep
   • Managing stress

   These habits can help boost your immune system and make you more resistant to infections.

4. Environmental measures:
   • Regular cleaning and disinfection of frequently touched surfaces
   • Proper ventilation in indoor spaces
5. Social distancing during outbreaks: Avoiding close contact with infected individuals and crowded places during flu season can reduce your risk of exposure.

How Can You Prevent Spreading Type A Flu if You’re Infected?

If you do contract Type A influenza, it’s important to take steps to prevent spreading it to others:

• Stay home: Avoid going to work, school, or public places while you’re contagious (typically up to 5-7 days after symptom onset)
• Cover your mouth and nose: Use a tissue when coughing or sneezing, and dispose of it properly
• Wear a mask: If you must be around others, wear a mask to reduce the spread of respiratory droplets
• Avoid close contact: Keep your distance from others, especially those at high risk for complications
• Clean and disinfect: Regularly clean surfaces you touch to prevent the spread of the virus

The Global Impact of Type A Influenza

Type A influenza has a significant impact on global health and economics. Its ability to cause widespread outbreaks and potentially lead to pandemics makes it a major focus of public health efforts worldwide.

How Does Type A Flu Affect Global Health?

The impact of Type A influenza on global health is multifaceted:

• Annual epidemics: Seasonal flu, often caused by Type A strains, affects millions worldwide each year
• Mortality: The World Health Organization estimates that annual flu epidemics result in about 290,000 to 650,000 deaths globally
• Pandemic potential: Type A viruses have caused several pandemics in history, including the 1918 Spanish flu and the 2009 H1N1 pandemic
• Economic burden: Flu outbreaks lead to increased healthcare costs, lost productivity, and strain on healthcare systems
• Research and surveillance: Significant resources are dedicated to monitoring flu activity and developing new vaccines and treatments

Understanding the global impact of Type A influenza underscores the importance of individual prevention efforts and supports ongoing research and public health initiatives aimed at mitigating its effects.

Emerging Research and Future Directions in Type A Influenza Management

The field of influenza research is dynamic, with ongoing efforts to improve prevention, diagnosis, and treatment of Type A flu. Some of the most promising areas of research include:

What New Developments Are on the Horizon for Type A Flu?

1. Universal flu vaccines: Researchers are working on developing vaccines that could provide protection against a wide range of influenza strains, potentially eliminating the need for annual vaccinations.
2. Improved antiviral drugs: New antiviral medications with different mechanisms of action are being studied to combat drug resistance and provide more effective treatment options.
3. Advanced diagnostic tools: Rapid, highly accurate diagnostic tests that can differentiate between viral strains are in development, which could lead to more targeted treatment approaches.
4. Gene editing techniques: CRISPR and other gene editing technologies are being explored as potential tools for creating flu-resistant cells or developing new treatments.
5. AI and big data in flu forecasting: Advanced computational methods are being used to predict flu outbreaks and inform public health responses.
6. Novel delivery methods for vaccines: Researchers are exploring alternatives to traditional injections, such as nasal sprays or patch-based vaccines, which could improve vaccine uptake and efficacy.

These emerging areas of research hold promise for revolutionizing our approach to Type A influenza management in the coming years. As our understanding of the virus and our technological capabilities advance, we may see significant improvements in our ability to prevent, diagnose, and treat this perennial health threat.

Type A Influenza: Symptoms, Treatment, and Prevention

Type A influenza is a common infection that can cause widespread flu outbreaks. It can cause fever, body aches, chills, fatigue, and other symptoms.

Influenza — also known as the flu — is a contagious viral infection that attacks your respiratory system.

Influenza viruses that infect humans can be classified into three main groups: A, B, and C. Type A influenza infection can be serious and cause widespread outbreaks and disease.

Common symptoms of type A infection can be confused with other conditions. While in some milder cases the flu can resolve on its own without significant symptoms, severe cases of type A influenza can be life-threatening.

Unlike a common cold, the flu typically occurs with a sudden onset of symptoms. Common signs of an influenza infection include:

• coughing
• runny or stuffy nose
• sneezing
• sore throat
• fever
• headache
• fatigue
• chills
• body aches

Sometimes, influenza A symptoms may resolve on their own. However, if symptoms persist for more than a week without improvement, schedule a visit with your doctor.

People who are at high risk for flu complications, such as those who are 65 years old and up or who have weakened immune systems, should seek immediate medical treatment. In rare cases, the flu can be deadly.

Left untreated, the flu can cause:

• ear infection
• diarrhea
• nausea
• vomiting
• dizziness
• abdominal pain
• chest pain
• asthma attack
• pneumonia
• bronchitis
• cardiac issues

Types A and B influenza are the more common forms of this infection, routinely causing seasonal outbreaks. Type C influenza usually only causes mild respiratory infections.

Type B influenza can be just as severe as type A influenza but is less common throughout the flu season compared to type A.

Humans are the natural host for type B infection. Type B viruses mutate much slower than type A infections and are categorized by strains, but not subtypes. The B virus strains take longer for their genetic makeup to change than influenza A. This drastically reduces the risk of a widespread pandemic due to type B influenza.

Type A influenza can be dangerous and is known to cause outbreaks and increase your risk of disease. Unlike a type B infection, type A viruses are categorized by subtypes and strains. Influenza A mutates faster than influenza B, but both viruses are always changing, creating new strains from one flu season to the next. Past flu vaccinations will not prevent infection from a new strain.

Wild birds are the natural hosts for a type A virus, also called avian flu and bird flu. This infection can also spread to other animals and humans. This, combined with the ability of type A influenza to mutate faster than type B, can cause pandemics.

Before treating your condition, your doctor will need to check for the influenza virus. The preferred test is the rapid molecular assay. In this procedure, your doctor swabs your nose or throat. The test will detect influenza viral RNA within 30 minutes or less.

Results aren’t always accurate, and your doctor may have to make a diagnosis based on your symptoms or other flu tests.

In some cases, influenza A symptoms can clear on their own with ample rest and fluid intake. In other cases, your doctor may prescribe antiviral medication to fight the infection.

Common antiviral prescriptions include:

• zanamivir (Relenza)
• oseltamivir (Tamiflu)
• peramivir (Rapivab)

These medications, known as neuraminidase inhibitors, reduce the ability of the influenza virus to spread from cell to cell, slowing down the infection process.

Though effective, these medications can cause side effects such as nausea and vomiting. If you begin to experience any of these symptoms or if your condition worsens, stop using the prescription and visit your doctor immediately.

A new medication called baloxavir marboxil (Xofluza), created by a Japanese pharmaceutical company, was approved in October 2018 by the U. S. Food and Drug Administration (FDA). This antiviral drug helps stop the influenza virus from replicating.

Over-the-counter medication therapy can also ease flu symptoms. Be sure to stay hydrated to loosen mucus in your chest and strengthen your immune system.

How long is it contagious?

If you have the flu, you’re contagious from at least a day before you begin to experience symptoms up through five days after your symptoms begin.

In more severe cases, you could be contagious for even longer after you begin experiencing symptoms. This number can fluctuate if your immune system is weak or undeveloped, specifically in cases of children or older adults.

The best way to prevent the flu is through annual vaccinations. Each flu shot protects against three to four different influenza viruses within that year’s flu season.

Other ways to prevent spreading this disease include:

• washing your hands regularly
• avoiding large crowds, specifically during a flu outbreak
• covering your mouth and nose when you cough or sneeze
• staying home if you develop a fever and for at least 24 hours after it goes away

Type A influenza is a contagious viral infection that can cause life-threatening complications if left untreated. While some cases of this infection can improve without prescribed medication, a visit to your doctor is recommended. If you don’t already have a provider, our Healthline FindCare tool can help you connect to physicians in your area..

Don’t self-diagnose your condition. The flu can resemble the common cold, but may trigger worsening symptoms. If you think you’ve contracted influenza, schedule a visit with your doctor to discuss treatment.

A Parent’s Guide to the Flu

Johns Hopkins Children’s Center pediatric infectious disease specialist Pranita Tamma, M.D., shares insights for parents.

How can I best protect my child against the flu?

First, with your pediatrician’s OK, have your child vaccinated. Added prevention is also key. Teach your child how to wash his or her hands when he or she is in school or away from home with either soap and water or an alcohol-based hand rub.

The flu virus spreads mainly by droplets when infected people cough, sneeze, or even talk, but it can be spread by touching surfaces on which one of those droplets has landed and then touching one’s nose, mouth or eyes. This is why hand washing is so important – both for the person with the flu and others around him or her. If someone in your household has the flu, ask your doctor if preemptive antiviral medication is an option for others in the home. Clean common surfaces like the kitchen counter, bathroom sink, light switches, door knobs, etc., frequently with household disinfectants.

If your child has the flu, keep him or her home from school, daycare and any other activities that could expose others to the virus. If your child needs to go outside of the house, he or she should wear a mask to reduce the likelihood of spreading the virus to others.

We urge that children six months and older be vaccinated, especially those at risk for complications from the flu. Your child’s pediatrician will know what’s best for your child, especially if there are preexisting conditions, including allergies, that require careful review.

What are its symptoms?

The symptoms of the seasonal flu include a fever (temperature of 100°F or greater), as well as a headache, sore throat, extreme fatigue and body aches, coughing, sneezing, runny nose, vomiting and/or diarrhea.

How should I treat it?

Consider giving your child acetaminophen (Tylenol) or ibuprofen (e.g. Advil or Motrin) as directed on the bottle for fevers, headache and body aches, or by your pediatrician. Have your child drink plenty of fluids to stay hydrated. This is especially important if your child has a high fever, vomiting or diarrhea. Keep your child apart from other members of the household, help him or her rest and keep him or her at home at least 24 hours after fever and other symptoms subside.

Do not share eating utensils, drinking glasses, washcloths, towels, beds, pillows, etc. until everyone in the household has been free of symptoms for five days.

Because the flu is caused by a virus it does NOT respond to antibiotics.

When should I seek medical treatment?

Children most likely to need medical treatment from their doctor for influenza infection are those who are very young or have serious medical conditions (such as asthma, cancer or lung disease, or who are on dialysis). If you think your child needs medical treatment, call your pediatrician’s office first. Your doctor may want to speak with you over the phone and recommend treatments rather than have you come into the office, where your child can infect other people.

How long is the incubation period and how long does the contagious phase last? 

Most healthy children and adults with the flu can infect others beginning about one day before developing any symptoms and up to seven days after the symptoms resolve. People with weakened immune systems can remain contagious for up to several weeks.

Is it possible to get the flu even after vaccination?

Getting a flu vaccine greatly reduces the risk of getting the flu but it does not guarantee that a child will not get the flu. In developing the vaccine, physicians and scientists make a best guess based on recent flu patterns to determine the most likely flu strains for the season. Unfortunately, there can be strains circulating in the environment that are not in the vaccine. The flu vaccine includes three strains of the influenza virus. The good news is that even if the vaccine strains and the circulating strains are not perfect matches, the vaccine can still provide some protection because viral strains share similarities. It takes about two weeks for the vaccine to elicit the proper protective response, so if someone is infected soon after receiving the vaccine, or if he or she was exposed to the virus before receiving the vaccine, symptoms can still develop.

Is the flu vaccine safe for kids with allergies?

Even though the flu vaccine contains egg protein, most children with egg and other food allergies can be immunized safely with a few basic precautions.

Children with established diagnoses of severe egg allergy should not be immunized without consulting a pediatric allergist. Most, however, can be vaccinated safely after a skin-prick test to the vaccine itself to gauge the risk for a reaction. Children with suspected yet unconfirmed allergies and those with mild egg allergies can usually be vaccinated in their pediatrician’s office.

An estimated 2 percent to 3 percent of U.S. children are allergic to eggs. Leaving them unprotected against the flu can lead to many unnecessary yet preventable infections and hospitalizations. Many children with food allergies also have asthma, putting them at even higher risk for complications from the flu. Pediatricians should make special efforts to vaccinate those at high risk for complications, according to the American Academy of Pediatrics (AAP).

Can children recently immunized “shed” the vaccine or virus to others? 

Such transmission of an attenuated influenza strain is very uncommon, perhaps because only low titers of vaccine virus are shed.

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They are regularly found in most people, have characteristic signs and a development mechanism. There are more than 200 viruses that can cause this pathology. Depending on the type of virus, its activity and the patient’s condition, the disease can proceed in different ways: from mild to aggravated forms. The most dangerous in this regard is the flu – it can cause complications on various organs and systems. Diagnosis of viral infections of the respiratory system is extremely important in epidemiological terms, as well as to confirm the diagnosis. Various methods are used, the choice of which depends on the specific clinical case.

SARS and influenza have respiratory symptoms and are common. They can be recognized by catarrhal signs of the respiratory tract and general symptoms characteristic of most diseases.

Modern diagnostic methods for this group of diseases

There are several types of diagnostics, which differ in the features of the conduct and the method of identifying the pathogen.

Express methods

This is a quick way to confirm or rule out the presence of a disease. The method of fluorescence and PCR is used.

Let’s consider them in more detail:

• Study of fluorescent antibodies – MFA. The method is based on the determination of antigens to the virus in the epithelial cells of the nasal mucosa, on the conjunctiva (if there are eye lesions). Antibodies under the action of an antigen react with a specific luminescence, which is easy to see under microscopic examination. This parameter is considered a diagnostic marker and is the basis for confirming the result. The method has diagnostic value from 3 to 5 days of illness. Sensitive to such antigens: influenza virus type A, B, parainfluenza virus, adenoviruses and the causative agent of RS infection. This is a convenient and fast method that does not require special resources, and is often used during diagnostics.

• The polymerase chain reaction method is based on the detection of nucleic acid regions of the genetic material of the virus and the determination of their group affiliation according to this criterion. The technique has a high diagnostic value, is a modern and high-quality way to confirm the disease. It is considered the “gold standard” of diagnostics, since it does not give false results and is specific for the detection of specific pathogens, it is widely used in inpatient and outpatient settings.

Virological methods

are based on the pure isolation of viral microorganisms and their specific strains, followed by their attachment to cell cultures in the laboratory. This is followed by the determination of the type of virus using PCR or other reactions. The method requires significant resources, rather long and laborious. Its value lies in obtaining epidemiological data and the basis for scientific work. That is, a detailed study of the virus, the frequency of its spread makes it possible to predict the epidemic picture and create vaccines. For research, a swab is taken from the nose and nasopharynx. The material is suitable for 3-5 days of illness. Using virological methods, the following pathogens can be identified:

• influenza A virus;
• influenza virus B.

Serological diagnostic methods

This is a retrospective study that provides accurate data regarding the stage of the process, the degree of activity and the type of pathogen. Used for epidemiological purposes.

For analysis, blood serum is used, in which it is necessary to determine the amount and types of antibodies. A known antigen of the virus is used. When a reaction occurs with the patient’s material, antigen-antibody immune complexes are formed, which confirms the diagnosis. An increase in antibody titer is also important for diagnosis, for which paired sera are used.

The result has a high accuracy and can be determined even if all other methods have failed, as it has a high sensitivity. it is especially important to use the method for erased forms with minimal clinical manifestations. Sera for analysis are taken at the onset of the disease, as well as 10-14 days after its completion. A method is used to confirm the presence in the body of such pathogens: influenza viruses A, B, parainfluenza pathogens, adenoviruses and RS viruses.

The presence of the influenza virus can be confirmed with the help of RTGA – hemagglutination inhibition test. The method is based on the property of reducing the hemagglutinating abilities of the virus if there are antibodies to it in the blood. For this, blood with red blood cells, an antigen is used. Blood products are taken in pairs, at the onset of the disease, and during the recovery period. The method has a high diagnostic value, accurate and sensitive.

Types of test material and delivery features

For diagnosis, swabs from the nose, swabs from the nasal passages, nasopharynx, as well as blood products are used.

Smear and washout is taken by medical personnel. He makes sure that the preparations strictly correspond to the proper localization. The sampling takes place in clean conditions, with sterile instruments and in a sterile container. Before taking smears, the patient is asked to blow his nose to clear the nasal passages of mucus. The probe is inserted easily, to a depth of 2-3 cm. A standard movement is carried out along the lower part of the nasal passage and under the nasal concha. It is necessary that the sampling takes place in a modern clinic, where it is possible to properly store and transport the collected material in a short time to the laboratory.

A swab from the pharynx is taken according to a similar technique to affect those areas of the mucosa on which the pathogen accumulates. Before sampling, it is necessary to rinse the mouth lightly so that the material taken is clean. It is advisable to take the material on the 3rd day after the onset of the disease.

Norms and deviations from them, interpretation of results

An express test gives results immediately after diagnosis, its decoding does not cause difficulties, as it determines the presence of a virus or its absence in the body.

Serological reactions are more complex and can be interpreted in different ways: the presence of class M antibodies indicates an acute stage of the process, G antibodies are formed during a chronic course.

Deadline for results

The results of the study are ready for 1-2 days after delivery. The express test gives the result immediately. Serological methods require more time to compare antibody titers. Faster methods are important for the diagnostic process, and those that are more expensive for epidemiological and scientific research.

The speed of diagnosis depends on the correct delivery of drugs, laboratory conditions, and the quality of reagents.

Timely analysis allows you to accurately and quickly determine the diagnosis. This is the key to correct and effective treatment. If the disease is started, it threatens with complications, which are especially dangerous if a person has the flu. This is true for children, the elderly, pregnant women and people with a deficient immune system, because complications are most often manifested in them.

Influenza

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2. INFO
3. Reminders
4. Influenza

02 October 2019
Views: 8004

Influenza

Probably everyone has experienced the flu at least once in their life. And this is not surprising, because influenza is one of the most common infectious diseases that can lead to massive outbreaks and even epidemics almost every year. Therefore, it is so important to know the “enemy in the face”: how dangerous it is, how to defend against it, and how it is easiest to endure.

Why is influenza so common? Why do so many adults and children around the world suffer every year from this ubiquitous disease, which can lead to very serious complications?

The influenza virus is highly variable. Every year, new subspecies (strains) of the virus appear that our immune system has not yet encountered and, therefore, cannot easily cope with. That is why flu vaccines cannot provide 100% protection – there is always the possibility of a new virus mutation.

The history of the flu

The flu was known to mankind many centuries ago. The first documented influenza epidemic occurred in 1580. True, at that time nothing was known about the nature of this disease.

The pandemic of respiratory infection in 1918-1920, which took over the globe, and was called the “Spanish flu”, was most likely nothing more than an epidemic of the most severe influenza. It is known that the Spaniard was distinguished by incredible mortality – with lightning speed it led to pneumonia and pulmonary edema, even in young patients.

Reliably the viral nature of influenza was established in England only in 1933 by Smith, Andrews and Laidlaw, who isolated a specific virus that mainly affects the respiratory tract from the lungs of hamsters infected with a swab from the nasopharynx of influenza patients and designated them as influenza A virus. B 1940 g Francis and Magil discovered the influenza virus B, and in 1947 Taylor isolated another new version of the influenza virus – C.

Since 1940, it became possible to actively study the influenza virus and its properties – the virus began to be grown in chicken embryos. Since then, a big step forward has been made in the study of influenza – the ability to mutate has been discovered, and all parts of the virus capable of variability have been identified. An important discovery, of course, was the creation of a vaccine against influenza.

What is influenza

Influenza is an acute viral disease that can affect the upper and lower respiratory tract, is accompanied by severe intoxication and can lead to serious complications and deaths, mainly in elderly patients and children.

Influenza is a type of acute respiratory viral infection (ARVI), and according to the method of infection, and according to the main manifestations, all ARVI are similar. But the flu causes much more intoxication, is often severe and leads to various complications.

Influenza virus

In order to correctly form ideas about this disease and predict the situation, you need to understand its structure:

• RNA-containing virus;
• The influenza virus has internal and surface antigens: internal antigens – NP (which makes up the capsid itself) and M (a layer of matrix and membrane proteins) – NP and M are type-specific antigens, so synthesized antibodies do not have a significant protective effect. Outside of these structures, there is a lipoprotein shell that carries external antigens – 2 complex proteins (glycoproteins) – hemagglutinin (H) and neuraminidase (N)
• According to the antigenic structure, the influenza virus is divided according to the antigenic principle into types A, B, C, and the disease can be represented by one of the antigenically independent viruses (it happens that during epidemics and pandemics 2 types of viruses are recorded at once). Basically, epidemics are caused by types A and B, pandemics by type A.
• Influenza A virus is divided into 13 H subtypes (H1-H13) and 10 N subtypes (N1-10) – the first 3 H subtypes and the first 2 N subtypes are dangerous for humans.
• Type A has high variability, there are 2 variants of variability: antigenic drift and antigenic shift. Drift is point mutations in the gene that control the H antigen, and shift is the complete replacement of one or both surface antigens at once, i.e. the entire RNA segment, as a result of the exchange of genetic material by human and animal influenza, and this leads to the emergence of new antigenic variants, to which lack of immunity, which is the cause of epidemics and pandemics. Epidemics can also occur during drift, because the slightest change in the genotype of the pathogen can “confuse the memory cells” of the immune system, and it turns out that the majority of the population is not immunized.

At the beginning of 2016, viruses similar to the swine flu of the 2009 pandemic A(h2N1)pdm09, strains of the influenza virus A(h2N1) with genetic changes (according to the Institute of Influenza), which are transmitted from person to person, are circulating among the human population, so call the current flu is purely “swine” is not entirely correct.

Causes of influenza

The source of the infection is a sick person. Viruses are shed in saliva, sputum, nasal secretions – when coughing and sneezing. Viruses can get on the mucous membranes of the nose, eyes or upper respiratory tract directly from the air, through close contact with a sick person; and can settle on various surfaces and then get on the mucous membranes through the hands or when using common hygiene items with the patient.

Then the virus enters the mucosa of the upper respiratory tract (nose, pharynx, larynx or trachea), enters the cells and begins to multiply actively. In just a few hours, the virus infects almost the entire mucosa of the upper respiratory tract. The virus “loves” the respiratory mucosa very much, and is not able to infect other organs. That is why it is incorrect to use the term “intestinal flu” – the flu cannot affect the intestinal mucosa. Most often, what is called intestinal flu – fever, intoxication, accompanied by diarrhea – is a viral gastroenteritis.

It is not clear exactly what protective mechanisms stop the reproduction of the virus and cause recovery. Usually, after 2-5 days, the virus ceases to be released into the environment; a sick person ceases to be dangerous.

Influenza symptoms

The incubation period for influenza is very short – from infection to the first manifestations of the disease, it takes on average from several hours to 2 days (A, C), less often up to 4 days (influenza B).

Influenza always begins acutely – the patient can accurately indicate the time of onset of symptoms.

According to the severity of the course, influenza is classified as mild, moderate and severe.

In all cases, in varying degrees, there are signs of intoxication and catarrhal phenomena. In addition, in 5-10% of cases there is also a hemorrhagic component.

Intoxication has the following manifestations:

• first of all, high fever: in mild cases, the temperature does not rise above 38ºС; with moderate flu – 39-40ºС; in severe cases – it can rise above 40 ºС,
• chills,
• headache – especially in the forehead, eyes; severe pain when moving the eyeballs,
• muscle pain – especially in the legs and lower back, joints,
• weakness,
• malaise,
• loss of appetite,
• may be nausea and vomiting.

Signs of acute intoxication usually persist for up to 5 days. If the temperature persists longer, there is likely to be some bacterial complication.

Catarrhal symptoms persist for an average of 7-10 days:

• Runny nose.
• Sore throat.
• Cough: in uncomplicated cases, this is usually a dry cough.
• Hoarseness of voice.
• Pain in the eyes, lacrimation.

Hemorrhagic events:

• Minor hemorrhages or vasodilation of the sclera
• Hemorrhages in the mucous membranes: this can be noticeable on the mucous membranes of the mouth, eyes
• Nosebleeds
• A very characteristic sign of influenza is reddening of the face with general pallor of the skin
• The appearance of hemorrhages on the skin is an extremely unfavorable sign in terms of prognosis.

Ah2N1 influenza may cause diarrhea.

Influenza symptoms requiring an ambulance call:

• Temperature 40 ºС and above.
• Preservation of high temperature for more than 5 days.
• Severe headache that does not improve with pain medication, especially in the back of the head.
• Shortness of breath, rapid or irregular breathing.
• Disturbance of consciousness – delirium or hallucinations, oblivion.
• Convulsions.
• The appearance of a hemorrhagic rash on the skin.

If you experience any of these symptoms, or any other warning signs that are not part of the pattern of uncomplicated influenza, you should seek immediate medical attention.

Who suffers the flu more severely

Persons suffering from chronic cardiovascular diseases: especially congenital and acquired heart defects (especially mitral stenosis).
Persons suffering from chronic lung diseases (including bronchial asthma).
Patients with diabetes mellitus.
Patients with chronic kidney and blood diseases.
Pregnant.
Older people over 65 years of age, since in most cases they have some degree of chronic disease.
Children under 2 years of age and immunocompromised individuals are also susceptible to complications from influenza.

Complications of influenza

Viral complications of influenza

Primary viral pneumonia is an extremely severe complication of influenza. It is caused by the spread of the virus from the upper respiratory tract further along the bronchial tree and damage to the lungs. The disease is steadily progressing. At the same time, intoxication is expressed to an extreme degree, shortness of breath is observed, sometimes with the development of respiratory failure. There is a cough with scanty sputum, sometimes with an admixture of blood. Heart defects, especially mitral stenosis, predispose to viral pneumonia.

Infectious-toxic shock – an extreme degree of intoxication with impaired functioning of vital organs: in particular, the cardiovascular system (there is a pronounced increase in heart rate and a critical drop in blood pressure) and kidneys. The first manifestation of infectious-toxic shock.

Myocarditis and pericarditis as complications of influenza occurred during the Spanish flu pandemic. Currently extremely rare.

Bacterial complications of influenza

Influenza significantly reduces the natural resistance to other infections. The body spends all reserves on fighting the virus, so bacterial infections often join the clinical picture. Especially in the presence of any chronic bacterial diseases – all of them tend to worsen after the flu.

• Bacterial pneumonia. Usually after 2-3 days of the acute course of the disease, after the condition improves, the temperature rises again. There is a cough with yellow or green sputum. It is important not to miss the onset of this complication and start treatment on time with properly selected antibiotics.
• Otitis, sinusitis, frontal sinusitis. Bacterial inflammation of the sinuses and ear are perhaps the most common complications of influenza.
• Glomerulonephritis is an inflammation of the renal tubules, which is accompanied by a decrease in kidney function.
• Meningitis, encephalitis – inflammation of the meninges and/or tissue of the brain. It occurs most often in patients at risk, mainly those suffering from immunodeficiency.
• Septic conditions – conditions accompanied by the ingestion and subsequent multiplication of bacteria in the blood. Extremely serious conditions, often ending in death.

Treatment for influenza

Non-drug treatment for influenza

Quiet, better bed rest for 5 days. It is not necessary during the acute period of the disease (no matter how much you would like to) read, watch TV, work at the computer. This exhausts the already weakened body, prolongs the time of illness and the risk of complications.

Plentiful warm drink of at least 2 liters per day. Better rich in vitamin C – tea with lemon, rosehip infusion, fruit drink. Drinking a large amount of liquid every day, a sick person conducts detoxification – i.e. accelerated elimination of toxins from the body, which are formed as a result of the vital activity of viruses.

Antiviral therapy

Intranasal interferon: leukocytic 5 drops in the nose 5 times a day, influenzaferon 2-3 drops 3-4 times a day for the first 3-4 days.
Anti-influenza γ-immunoglobulin is administered to patients suffering from immunodeficiency
Rimantadine is an antiviral agent. It is better to start treatment with rimantadine on the first day of the disease, and at least not later than 3 days. It is NOT recommended to take the drug to children under 12 years of age, pregnant women, people suffering from chronic diseases of the liver and kidneys. NOT effective for “swine flu”. Treatment continues for 3 days.
Oseltamivir (Tamiflu). Treatment should begin on the first day of illness. The advantage of oseltamivir is the possibility of prescribing to children under 12 years of age and effectiveness against the Ah2N1 virus. The course of treatment is 3-5 days.

Non-specific drug therapy for influenza

– Non-steroidal anti-inflammatory drugs: paracetamol, ibuprofen, diclofenac. These drugs have an anti-inflammatory effect, reduce body temperature, and reduce pain. It is possible to take these drugs as part of medicinal powders such as Coldrex, Tera – flu, etc. It should be remembered that it is not worth lowering the temperature below 38ºС, since it is at this body temperature that defense mechanisms against infection are activated in the body. Exceptions are patients prone to convulsions and small children.

Children should not take aspirin. Aspirin in a viral infection can cause a serious complication – Reye’s syndrome – toxic encephalopathy, which is manifested by epileptic seizures and coma.

– Antihistamines are medicines used to treat allergies. They have a powerful anti-inflammatory effect, so they reduce all signs of inflammation: nasal congestion, swelling of the mucous membranes. The drugs of the first generation of this group – diphenhydramine, suprastin, tavegil – have a side effect: they cause drowsiness. Second-generation drugs – loratadine (claritin), fenistil, semprex, zyrtec – do not have this effect.

– Nasal drops. Vasoconstrictive drops for the nose reduce swelling, relieve congestion. However, this is not as safe a drug as it might seem. On the one hand, during SARS it is necessary to apply drops to reduce swelling and improve the outflow of fluid from the sinuses to prevent the development of sinusitis. However, frequent and prolonged use of vasoconstrictor drops is dangerous in relation to the development of chronic rhinitis. Uncontrolled intake of drugs causes a significant thickening of the nasal mucosa, which leads to dependence on drops, and then to permanent nasal congestion. Treatment of this complication is only surgical. Therefore, it is necessary to strictly observe the regimen for the use of drops: no longer than 5-7 days, no more than 2-3 times a day.

– Nasal lavage. Against the common cold and for the prevention of diseases of the ENT organs, as well as complications, nasal lavage is used. However, most nasal aerosol solutions involve irrigating the nose rather than directly rinsing. Irrigation, unlike rinsing, can only reduce the thick consistency of nasal secretions, but will not solve the problem of removing them along with harmful bacteria. After irrigation, the mucous membrane dries up quickly, which further aggravates the runny nose, provokes swelling. Washing also helps to reduce inflammation, improve the functioning of the nasal mucosa and reduce the development of complications of the disease. The modern technique involves washing the nasal passages with special antiseptic agents. For example, the components of the drug “Dolphin” get to the sinuses, diluting mucus clots and naturally bringing them out.

– Sore throat treatment. The most effective remedy (and the most unloved by many) is gargling with disinfectant solutions. You can use infusions of sage, chamomile, as well as ready-made solutions, such as furatsilin. Rinsing should be frequent – once every 2 hours. In addition, disinfectant sprays can be used: hexoral, bioparox, etc.

– Cough preparations. The goal of cough treatment is to reduce the viscosity of sputum, making it thin and easy to cough up. The drinking regimen is also important for this – a warm drink dilutes sputum. If you have difficulty coughing, you can take expectorant drugs, such as ACC, mukaltin, broncholithin, etc. You should not take drugs that suppress the cough reflex on your own (without consulting a doctor) – this can be dangerous.

– Antibiotics should not be used. Antibiotics are completely powerless against viruses, they are used only in the event of bacterial complications . Therefore, you should not use antibiotics without a doctor’s prescription, no matter how much you would like to. These are drugs that are not safe for the body. In addition, uncontrolled use of antibiotics leads to the emergence of resistant forms of bacteria.

Influenza Prevention

First of all, it is important to prevent viruses from getting into the mucous membranes of the nose, eyes or mouth. To do this, it is necessary to limit contact with sick people. In addition, it must be remembered that viruses can linger for some time on the personal hygiene items of a sick person, as well as on various surfaces in the room where he is. Therefore, it is important to wash your hands after contact with objects that may harbor viruses. You should also not touch your nose, eyes, mouth with dirty hands.

It should be noted that soap certainly does not kill influenza viruses. Washing hands with soap and water causes the mechanical removal of microorganisms from the hands, which is quite enough. As for the various disinfectant hand lotions, there is no convincing evidence that the substances they contain have a detrimental effect on viruses. Therefore, the use of such lotions for the prevention of colds is completely unjustified.

In addition, the risk of contracting SARS directly depends on immunity, i.e. the body’s resistance to infections.

To maintain normal immunity it is necessary: ​​

Eat right and fully: food should contain a sufficient amount of proteins, fats and carbohydrates, as well as vitamins. In the autumn-spring period, when the amount of vegetables and fruits in the diet decreases, an additional intake of a vitamin complex is possible.

• Exercise regularly, preferably outdoors, including brisk walking.
• Be sure to observe the rest regimen. Adequate rest and proper sleep are extremely important aspects for maintaining normal immunity.
• Avoid stress.
• Stop smoking. Smoking is a powerful factor that reduces immunity, which has a negative impact on both the overall resistance to infectious diseases and the local protective barrier – in the nasal mucosa, trachea, and bronchi.

Influenza vaccine

Influenza vaccines are renewed annually. Vaccination is carried out with vaccines created against viruses circulating in the previous winter, so its effectiveness depends on how close those viruses are to the real ones. However, it is known that with repeated vaccinations, the effectiveness increases. This is due to the fact that the formation of antibodies – protective antiviral proteins – in previously vaccinated people is faster.

What vaccines are available?

3 types of vaccines have now been developed:

Whole virion vaccines – vaccines that are a whole influenza virus – live or inactivated. Now these vaccines are practically not used, because they have a number of side effects and often cause disease.
Split vaccines are split vaccines containing only part of the virus. They have significantly fewer side effects and are recommended for adult vaccination.
Subunit vaccines are highly purified vaccines that cause little or no side effects. May be used in children.

When is the best time to get vaccinated?

The best time to vaccinate is before the outbreak develops, between September and December. It is also possible to be vaccinated during an epidemic, but it must be borne in mind that immunity is formed within 7-15 days, during which it is best to carry out additional prophylaxis with antiviral agents – for example, rimantadine.

Vaccine safety:

As already mentioned, for greater safety it is better to use the most purified subunit vaccines.

Flu emergency

In the event of an outbreak in a closed community or during an influenza epidemic, the effectiveness of vaccination is significantly reduced, since it takes at least 1-2 weeks to develop full immunity.

Therefore, if vaccination has not been carried out, especially in people at risk, it is advisable to take prophylactic antiviral agents.

• Rimantadine is taken daily at the same time at a dose of 50 mg for no more than 30 days.