In 2009, swine flu left people around the world in fear and terror - after a short time, they had made the leap across the Atlantic Ocean from the first deaths and illnesses in Mexico. Many people feared a disaster of international proportions. In the media, a horror message first chased the other.
Assessments by experts on swine flu
The World Health Organization (WHO) also warned of a potential global epidemic ("pandemic") - it called for the highest level of security on 11 June. Experts have classed the swine flu pathogen as a health risk of international importance, comparable to the occurrence of SARS in 2003.
But there were also voices from experts who pleaded not to overestimate the danger. Thus, not only the numbers of people with swine flu and deceased have declined significantly, they were from the outset far below the casualty figures of the annual, seasonal flu.
What is swine flu?
Often, swine flu is misleadingly equated with swine influenza, a disease that has previously been found in pigs. The known since 2009 variant of the swine flu is caused by a novel, previously unknown flu virus. Swine flu viruses are among the type A influenza viruses that have been known since the Spanish flu shortly after the First World War.
These have numerous subtypes, which are referred to depending on the nature of the protein envelope with H for hemagglutinin and N for neuraminidase. Most of these subtypes are harmless or dangerous only to animals, the subtype influenza A (H1N1) is responsible for the "normal" influenza in humans. Typical of influenza viruses is that they are constantly changing and the new variants are therefore no longer recognized by the immune system. This is also the reason that the flu vaccine needs to be redone every year.
Why "swine flu"?
The new variant of subtype H1N1, commonly referred to as swine flu, is a so-called reassortant (also known as "antigenic shift"). This is a sudden mutation caused by two or more subtypes sharing their genetic material. This can make harmless, only dangerous for animals viruses, suddenly aggressive variants that can be transmitted in an unusual way and against the first time there is no immune protection. This is exactly what happened with the bird virus epidemic, for example.
Pigs are particularly predestined as a "hotbed" of such dangerous love affairs. This is because their immune system has receptors for the proteins (hemagglutinins) of various virus subtypes, so a cell can easily be infected with multiple viruses at the same time.
The current swine flu virus combines two strains of swine flu and one strain each of bird flu and influenza in humans. The symptoms of swine flu are thus similar to the symptoms of other influenza types; as distinguishing features only diarrhea and vomiting occur.
How is the swine flu transmitted?
The infection with swine flu takes place primarily from pig to pig and from pig to human. Meanwhile, it also shows that this aggressive variant of the swine flu can take the actually atypical distribution path from person to person. And that means that there are hardly any barriers left in our globalized world. No wonder that only two to three weeks passed from the first known cases in Mexico and the first appearance in Germany.
The symptoms of swine flu occur after an incubation period of one to four days; it is contagious from the beginning of the incubation period. The infection with swine flu takes place as in the case of ordinary influenza especially on droplets infected saliva, so for example when coughing, sneezing or kissing.
Contrary to the prevailing belief in the people of the day, it is not to be feared that swine flu will be consumed by eating pork.