Neue Influenza A (H1N1) 2009

In April 2009 a novel influenza virus A H1N1 causing high morbidity and mortality spread first on the plateau of Mexico City subsequently followed by distribution to Texas and California in USA and to Spain; finally within three weeks this influenza virus was worldwide distributed. Its haemagglutinin showed epitope structures that were not recognized by the immune system of children and young adults as a memory response. The pandemic influenza virus consisted of quasispecies with a mixture of genome parts from human, avian, and American and Eurasian swine origin. This new virus caused all symptoms typically for influenza as abrupt onset, fever >39 °C, sore throat with all signs of inflammation, myalgia and arthralgia. In summer 2009 all infections in Europe were mild, while until winter there was a higher lethality in Brazil, Mexico and Argentine; but still in winter 2009 in Europe the pathogenic action of the circulating virus was mild. European isolates showed a neuraminidase inhibitor resistance of around 10%. Prevention of spread of the novel influenza virus H1N1 2009 is mainly by hygienic measurements as: avoid contact to infected, distance from infected, hand disinfection, protection of eye and nose mucous membranes, avoid aerosol formation during blowing the nose and sneezing. It is recommended to use single way tissue handkerchiefs and to depose them in a covered waste reservoir. For further prevention of influenza virus transmission three different vaccines are available in Europe since October 2009. This virus or at least some genomic parts will persist in the human population for the next 2 years.