Flu and varieties of strains

The flu is one produced by the influenza virus, which belongs to the family orthomyxoviridae and affects birds and mammals, including man. Influenza epidemics occur in the winter months in the temperate zones of the planet: between October and March in the northern hemisphere, and between April and September in the southern hemisphere.

Strain types

exist different genres or types, the most important are A, B and C. They are distinguished from each other by the characteristics of their antigens (proteins that provoke the immune response). The most important outbreaks of influenza have been caused above all by type A. Type A has proteins or antigens on its surface (H and N) that they change every year and as a consequence there is more population without immunity against the virus and therefore susceptible to infection.

Periodically appear epidemics that end up affecting the entire planet, are what we call pandemics. They are usually caused by it. In the twentieth century there were 5 pandemics, including 1918-19 (the so-called Spanish flu), with more than 50 million deaths, and the last one in 1977 (known as the Russian flu).

Transmission, incubation and epidemics

Flu viruses or virus-laden saliva, which are spread by coughing or sneezing, but are also deposited on hands or inert surfaces. The flu has an incubation period of 1 to 3 days and affects the respiratory system. Flu epidemics start abruptly, peak in 2-3 weeks, last two to three months, and disappear almost as quickly as they appeared. In the epidemics are usually contagious between 10% and 20% of the population. The flu mortality It occurs in people with risk factors, the main ones being chronic heart or respiratory diseases and advanced age. diabetes and pregnancy (especially the second and third trimesters) are also risk factors for the flu and its complications.

Flu symptoms

The flu begins abruptly with general symptoms such as:

• Fever
• Headache
• muscle or joint pain
• Soft spot
• General discomfort
• respiratory symptoms (cough and sore throat).

The cough is usually dry and can last for several days or weeks. Unlike the simple ones, the flu can last between one and two weeks until full recovery, but the usual average is about 5 days.

The main complication is pneumonia, which can be fatal. Pneumonia or infection of the lung is accompanied by fever and shortness of breath (dyspnea). It can be caused by the virus itself or be a superinfection of the lung by bacteria. Another cause of mortality in affected people is due to the decompensation of underlying diseases, whether cardiac or respiratory.

Test to see if you have the flu

In most cases, the diagnosis is clinical, that is, it is based on the presence of symptom typical of influenza in the context of an epidemic. Internal Medicine specialist Advance Medical Consultant Physician