According to a report in last week’s Proceedings of the National Academy of Sciences on the identification of a new H5N1 virus sublineage in poultry, this new virus sublineage, called Fujian virus, appears to have become the dominant strain of the H5N1 avian influenza circulating in parts of Asia. If the report is confirmed, this does not come as a surprise, FAO and the World Organization for Animal Health (OIE) said today.

While there is a wide variety of avian influenza strains in animals, and influenza viruses in general have a high rate of change from season to season and from year to year, OIE Director-General Bernard Vallat and FAO’s Chief Veterinary Officer Joseph Domenech warn that with new antigens developing continually in avian influenza viruses, vaccines currently in use for poultry need to be assessed regularly.

The two organizations continue to recommend that vaccination control measures need to be accompanied by surveillance and post-vaccination monitoring. They also stressed the need to immediately report to veterinary authorities any unexpected poultry deaths.

Careful monitoring of vaccination campaigns recommended

Vaccination remains part of the FAO-OIE strategy to contain avian influenza and both organizations say that vaccination campaigns should be applied appropriately and carefully monitored according to FAO and OIE technical guidelines, including the use of a cold chain in order to protect the vaccine. Vaccination must be carried out along with other disease control measures, such as improved hygiene on the farm, animal movement management or market inspection and culling in case of outbreaks, said Dr. Domenech.

According to Dr. Vallat, “Commitment is needed from all governments to implement prevention and control programs such as surveillance of virus circulation and, where appropriate, vaccination programs in countries where the virus is endemic or where there is a high risk of introduction of the virus.”

FAO and OIE are already supporting such programs in key countries where the virus is still circulating. But, they say more information on control programs based on vaccination is needed and urge more research be funded to better understand the epidemiology and genetic changes of the H5N1 virus.