Synonyms
Influenza, real flu, virus fluOne can fall ill with influenza in the northern and southern hemisphere, the pathogens of influenza flu only occur in the local winter. Worldwide, about 500 million people fall ill with influenza every year. In Germany between 2001 and 2009, up to 1677 cases were detected annually.
However, these are only the reported cases, the number of unreported cases is many times higher. It is therefore similarly difficult to estimate the number of fatalities, a distinction is made between proven and unproven cases (up to 330 annually from 1998 to 2007). Infections with influenza virus type A are the most common and have the most severe course; influenza caused by influenza virus type B is the second most common and usually has a milder course.
Infections with influenza virus type C are very rare. Influenza virus type A is very contagious and can cause epidemics, which occur approximately every one to three years. One speaks of an epidemic when 10-20% of the population in a certain area and a certain period of time is ill.
If the disease spreads over countries or even continents, it is a pandemic, which in the case of influenza A type virus, occurs approximately every 10 to 15 years. Influenza virus type B, on the other hand, only causes local outbreaks of influenza. Modern flu rapid tests are able to detect influenza type A and B.
Most at risk are elderly people, pregnant women, infants and especially babies. In this group of people, the susceptibility to complications of influenza and thus mortality is higher than in others. Also at risk are people with previous heart, lung and immune system diseases. In principle, however, all age groups are at risk of contracting influenza.
