Ny influensastam, H1N2, påvisad hos gris i Sverige

According to a national serological screening performed in 2006, Sweden was free from influenza A/H1N2 at that time. This manuscript describes the first demonstration of influenza virus H1N2 in pigs in Sweden. It took place in a large sow pool unit during the winter 2008/2009, and influenza H1N2 was simultaneously demonstrated from coughing piglets in a satellite herd to that sow pool. In contrast, clinical disease was not reported from the other ten satellite herds of the sow pool. Pigs in Sweden were affected by in - fluenza A for the first time during the winter 1982/1983 (14) when H1N1 was introduced to the southwestern region of the country, and thereafter rather rapidly spread from there. The clinical signs of influenza during that winter were significant in all age categories of pigs, but have decreased with time and influenza has not caused major health disturbances since then. Influenza A/H3N2 was first diagnosed in a national serological screening carried out in 1999. This diagnose was made without previous signs of suspected disease, and the true entry of H3N2 into the country therefore remains un - known. Probably partial cross protection between subtypes of influenza A (11, 15, 19, 24) had reduced the severity of the clinical signs of H3N2 which allowed H3N2 to remain undiagnosed for an unknown period of time. Likewise the diagnose of H1N2 reported here is unlikely to be the index case of H1N2 in Sweden, since the herd affected was located in the middle of the country and employed fair biosecurity strategies. The significance of the large herd size on development of the clinical symptoms that lead to diagnose of the disease remains to be validated.