Definition | Influenza is an acute infectious disease of the upper respiratory tract with a viral nature of occurrence. It can be caused by a different combination of viruses, of which there are about 200, as well as bacteria. |
Specialty | Virology and microbiology |
History | In 1580, a large-scale flu pandemic was first documented, by which time the disease was nameless. Only in the XVI century in Italy, it was finally given the name “influenza”. In 1918-1920, the deadliest pandemic named the Spanish flu caused by the H1N1 virus occurred. In 1933, influenza of type A virus was first identified by virologists Wilson Smith, Christopher Andrews, and Patrick Laidlaw of the National Institute for Medical Research, London. In 1940, it became known that the influenza virus can be cultivated on chicken embryos, which significantly helped science in further research. |
Symptoms | The flu usually starts acutely. The severity of the disease depends on many factors: general health, age, whether the patient has previously been in contact with this type of virus. In the case of a mild form of influenza, body temperature may remain normal or rise no higher than 38 ° C, symptoms of infectious toxicosis are mild or absent. |
Causes | The cause of the disease are the seasonal viruses (autumn and winter). There are different types of influenza: A, B, and C. Mild forms of the disease are caused by type C. |
Virology | The most common route of transmission of infection is airborne. When coughing, sneezing, talking, particles of saliva, mucus, sputum with pathogenic microflora, including influenza viruses, are ejected from the nasopharynx of a patient or virus carrier. |
Prevention | Influenza vaccination is an effective means of preventing the disease. It is recommended to get vaccinated in September or October. WHO annually recommends this to people at risk and workers in certain professions. These categories include pregnant women, children from 6 months to 5 years old, the elderly and people with chronic diseases, medical workers, teachers, educators, salespeople. |
Diagnostic Method | Influenza is diagnosed by clinical manifestations. If identification of the etiological factor is required, rapid tests are used to detect viral antigen, tests of samples from the throat, nose, RT-PCR method. |
Treatment | If the person is not at high risk, influenza is treated symptomatically. Usually, bed rest, plenty of warm drink, taking antipyretic, antitussive drugs, isotonic water for washing the nasal cavity, and vasoconstrictor drops are assigned. Any remedy for colds and flu should be prescribed by a doctor. In severe conditions and complications, treatment is carried out in a hospital. |
Duration | If the flu proceeds without complications, the febrile period lasts 2-4 days and the illness ends within 5-10 days. Repeated rises in body temperature are possible, but they are usually due to the layering of the bacterial flora or other viral respiratory infection. Post-infectious asthenia may persist for 2-3 weeks after the flu: fatigue, weakness, headache, irritability, and insomnia. |
Prognosis | Flu patients require constant monitoring by health workers, but, unfortunately, about 30% of patients are hospitalized late – after 5-6 days of illness, which leads to a protracted course of pneumonia and other complications. |
Complications | The most common complication of influenza is pneumonia, as well as rhinitis, sinusitis, bronchitis, otitis media. Complications of the cardiovascular system are more common in the elderly. Myocarditis and pericarditis (an inflammatory disease of the muscles of the heart that can lead to heart failure) also may develop. |
Frequency in Population | A clear dependence of the level of morbidity of the urban population on the population of the city is revealed. The highest epidemic incidence of acute respiratory infections was observed in cities with a population of 1 million or more – 29.7%; in cities with a population of 500 thousand to 1 million – 24.1%. In cities with a population of less than 500 thousand – 22%. |
Deaths | CDC estimates that flu has resulted in 9 million – 41 million illnesses, 140,000 – 710,000 hospitalizations, and 12,000 – 52,000 deaths annually between 2010 and 2020. |
Society | In society, influenza is usually regarded as simple “seasonal cold” which may lead to dangerous delusions about not needing a vaccination for it. |