Influenza is an acute infectious disease caused by influenza viruses, characterized by severe symptoms including fever, headache, myalgia, fatigue, and respiratory symptoms. These viruses belong to the Orthomyxoviridae family and are divided into four main genotypic groups: A, B, C, and D. The most significant in terms of epidemiology and pathology are influenza viruses of types A and B. The infection is transmitted by airborne droplets, and its spread can lead to epidemics and pandemics. Influenza is especially dangerous for high-risk groups, such as the elderly, children, and people with underlying diseases. The pathogenesis of influenza occurs through direct damage to the respiratory tract, leading to the development of pneumonia and other serious complications.
History of the disease and interesting historical facts
Influenza has a long and storied history dating back to ancient times. The first recorded cases of the disease date back to ancient China, where similar symptoms were described. In the 18th and 19th centuries, influenza began to cause numerous epidemics, which contributed to an improved clinical understanding of the disease. One of the most famous historical facts is the Spanish flu pandemic of 1918-1919, which killed an estimated 50 to 100 million people worldwide. Based on this event, the first scientific studies aimed at studying the virus and its pathogenesis appeared.
Epidemiology
According to the World Health Organization (WHO), every year, 5 to 10% adults and 20 to 30% children fall ill with influenza. During epidemic seasons, the number of cases can increase significantly. Influenza A (H1N1) and A (H3N2) actively cause morbidity, especially in people with chronic diseases. Epidemiological studies show that in European countries, annual hospitalization rates due to influenza range from 1 to 3 cases per 1,000 people. Antigenic changes in the virus also play an important role in the dynamics of epidemics, leading to the emergence of new subtypes to which the population has no immunity.
Genetic predisposition to this disease
Research shows that genetic predisposition to influenza may be associated with several genes whose members are responsible for the production of interferons and other components of the immune response. The IFITM3 gene, for example, is associated with protecting cells from viruses, including influenza viruses. Mutations in this gene can reduce the body's resistance to infection. Also, polymorphisms in the HLA genes can predispose to a more severe course of the disease. However, these genetic markers require further research to better understand their role.
Risk factors for the development of this disease
Risk factors that increase the likelihood of contracting influenza can be divided into physical and chemical:
- Age (especially children and the elderly);
- Chronic diseases (eg asthma, cardiovascular diseases);
- Decreased immunity (as a consequence of HIV or during treatment with immunosuppressants);
- Unfavorable socio-economic conditions (overpopulation, lack of access to medicine);
- Lack of vitamins and microelements;
- Smoking and alcohol abuse;
These factors can increase both the likelihood of infection and the likelihood of complications.
Diagnosis of this disease
Diagnosis of influenza includes clinical assessment and laboratory tests. The main symptoms of the disease are:
- Fever (above 38°C);
- Cough;
- Sore throat;
- Myalgia;
- Fatigue and general weakness.
Laboratory tests include polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and rapid antigen testing. Radiological examinations are rarely used, but chest X-ray may be used if pneumonia is suspected. Differential diagnosis includes diseases such as coronavirus infection, respiratory viral infections, and acute respiratory infections.
Treatment
Treatment of influenza is divided into general and specific. General treatment includes:
- Bed rest;
- Air humidification;
- Drink plenty of fluids (water, tea, juices).
Specific pharmacological treatment includes antiviral drugs such as oseltamivir and zanamivir. Surgical treatment is generally not used, although drainage of pneumonia may be required in some cases. Other treatments include symptomatic treatments: antipyretics and anti-inflammatory drugs.
List of medications used to treat this disease
- Oseltamivir;
- Zanamivir;
- Paracetamol;
- Ibuprofen;
- Acetaminophen.
These drugs help relieve symptoms and reduce the burden on the immune system.
Disease monitoring
Monitoring the patient's condition includes regular control stages in dynamics:
- Body temperature assessment;
- Monitoring oxygen saturation levels;
- Assessment of symptoms.
The prognosis with adequate treatment is usually good, but complications such as pneumonia, myocarditis, and the use of antibiotics to prevent secondary bacterial infection are possible.
Age-related features of the disease
In children, flu can manifest itself with pronounced symptoms, including vomiting and diarrhea. In older people, the disease can proceed with sluggish symptoms, but with an increased risk of complications. In the middle age group, the disease also manifests itself with standard symptoms, but in the presence of concomitant diseases, the risk of complications increases.
Questions and Answers
- How can you prevent the flu? Vaccination is the main method of prevention, and you should also avoid contact with sick people and follow hygiene rules.
- How long does the flu last? Flu usually lasts from 5 to 7 days, but a prolonged course may indicate complications.
- Should the flu be treated with antibiotics? Antibiotics are not effective against viruses; they are used only in the presence of bacterial complications.
- How long is a person with the flu contagious? The patient may be contagious 1 day before symptoms appear and for 5-7 days after they appear.
- Is it possible to get the flu several times during a season? Yes, this is possible, especially if the viruses have different subtypes.
Advice from Dr. Oleg Korzhikov
Every flu season, I recommend my patients to get vaccinated, as this is the best way to protect themselves from a severe course of the disease. It is also important to follow general recommendations: get enough sleep, eat a balanced diet, and avoid stress. If you notice symptoms, start treatment as soon as possible, as antiviral drugs are effective only during the first day of illness. Do not forget that even after recovery, you should continue to follow hygiene rules so as not to infect others.
