New Terminology for Flu Virus Infecting Humans

3 January 2012, at 11:32pm

GLOBAL - Standardisation of the terminology for the variant A(H3N2) virus recently infecting humans has been agreed by FAO, OIE and WHO. The virus, which has been found in 12 human cases in the US, has several genes from a virus known to have been circulating in North American pigs.

FAO, OIE and WHO continue working closely together to address influenza issues related to public health and animal health.

Since July 2011, 12 human cases of infection with a variant influenza A(H3N2) virus have been detected in the United States. To date, no report has been received from elsewhere in the world. This virus has different virological characteristics from current circulating seasonal influenza viruses in humans, and has a new gene constellation: seven genes from the triple reassortant A(H3N2) viruses known to have been circulating in pigs in the North America and the M gene from an A(H1N1)pdm09 virus, a seasonal virus currently circulating in humans.

In order to improve communications and avoid confusion, FAO, OIE and WHO have established a working group of experts to standardise the terminology for variant influenza viruses. The joint recommendation for the above mentioned A(H3N2) virus is: A(H3N2)v , where "v" stands for "variant".

An example of use of the terminology: Sporadic human cases of infection with a variant influenza A(H3N2) virus A(H3N2)v have been reported in the USA. The A(H3N2)v virus is different from seasonal viruses currently circulating in humans.