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Wednesday, November 08, 2006

Bird Flu Is Changing

According to areport in last week's Proceedings of the National Academy of Sciences onthe identification of a new H5N1 virus sublineage in poultry, this newvirus sublineage, called Fujian virus, appears to have become the dominantstrain of the H5N1 avian influenza circulating in parts of Asia.

If thereport 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 toseason and from year to year, OIE Director-General Bernard Vallat and FAO Chief Veterinary Officer Joseph Domenech warn that with new antigensdeveloping continually in avian influenza viruses, vaccines currently inuse for poultry need to be assessed regularly.

The two organizations continue to recommend that vaccination controlmeasures need to be accompanied by surveillance and post-vaccinationmonitoring. They also stressed the need to immediately report to veterinaryauthorities any unexpected poultry deaths.

Vaccination remains part of the FAO-OIE strategy to contain avianinfluenza and both organizations say that vaccination campaigns should beapplied appropriately and carefully monitored according to FAO and OIEtechnical guidelines, including the use of a cold chain in order to protectthe vaccine. Vaccination must be carried out along with other diseasecontrol measures, such as improved hygiene on the farm, animal movementmanagement or market inspection and culling in case of outbreaks, said Dr.Domenech.

According to Dr. Vallat, "Commitment is needed from all governments toimplement prevention and control programs such as surveillance of viruscirculation and, where appropriate, vaccination programs in countries wherethe virus is endemic or where there is a high risk of introduction of thevirus."

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

FAO, the OIE and a myriad of scientific experts on avian influenza have repeatedly called upon scientists around the world to share their findingsand virus strains in a timely and transparent fashion. The OIE/FAO AvianInfluenza Laboratory Network with its secretariat in Padova, Italy (OFFLU - is a platform where member countries and scientistscan share valuable information with the international veterinary andmedical community. It is imperative that global health concerns and timelyinformation sharing override lags in the scientific publications approvalprocess, which may take from a few months to more that a year.

It is essential during outbreaks that pathogens, such as highlypathogenic avian influenza virus, be isolated from clinical cases and thatany changes in the character of the virus be monitored to ensure thatvaccine manufacturers are producing vaccines complying with OIE standardswhich are effective against virus strains in circulation, says Dr.Domenech.

Should the changes be significant enough to warrant reformulation ofthe vaccine, FAO and the OIE say it would be in the best interest of global health for this to be done by national governments and commercial vaccine companies.


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