The emergence of the pandemic A/H1N1 2009 virus and its characteristics.

April 2009 saw the emergence of a pandemic strain of influenza A H1N1 in North America. The virus is now prevalent worldwide in human populations and has become a significant public health problem with substantial economic and other consequences. The virus contains a combination of genes from influenza viruses previously known to circulate in pigs, birds, and humans. The human-animal interface is known to play an important role in the emergence of pandemic influenza viruses, and animals have occasionally been infected with the pandemic H1N1 virus. There is no evidence, however, that animals are playing a significant role in the epidemiology of this current pandemic. With regards to the implications for animal health, OIE recommends enhanced surveillance for the pandemic H1N1 virus in animals so that any changes in the characteristics of the virus that may threaten human or animal health are detected early. Several OIE Members have reported occurrences of the pandemic H1N1 virus in animals to the OIE as an emerging disease; its occurrence has been reported in pigs in several countries and on one occasion in turkeys. The limited number of documented animal infections have been associated with mild disease and infection of pigs with pandemic H1N1 virus is not considered to be a risk to food safety. OFFLU--the joint OIE-FAO network of expertise on animal influenza--is facilitating exchange of up-to-date technical information about diagnostics, surveillance and the characteristics of the pandemic H1N1 influenza virus in animals. OFFLU is also responsible for collaborating with the human health sector on animal influenza matters that are relevant to public health.