8 November 2006 A reported change in the bird flu virus comes as no surprise but underscores the need to assess regularly vaccines currently in use for poultry, the United Nations Food and Agriculture Organization (FAO) said today.
According to a report in last week’s Proceedings of the United States National Academy of Sciences, a new H5N1 virus sublineage in poultry, called Fujian virus, appears to have become the dominant strain of bird flu in parts of Asia.
In a joint statement with the Paris-based inter-governmental World Organization for Animal Health (OIE) FAO noted that 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,” FAO said in a news release.
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.
More information on control programmes based on vaccination in countries where the virus is endemic or where there is a high risk of introduction of the virus is needed, they said, calling for more research funding to better understand the epidemiology and genetic changes of the H5N1 virus.
It is essential during outbreaks that pathogens, such as highly pathogenic avian influenza virus, be isolated from clinical cases and that any changes in the character of the virus be monitored to ensure that vaccine manufacturers are producing vaccines complying with OIE standards which are effective against virus strains in circulation, FAO’s Chief Veterinary Officer Joseph Domenech warned.
Although well over 200 million birds have died worldwide from either the virus or preventive culling, there have so far been only 256 human cases, 152 of them fatal, since the current outbreak started in South East Asia in December 2003, and these have been ascribed to contact with infected birds.
But experts fear the virus could mutate, gaining the ability to pass from person to person and, in a worst case scenario, unleash a deadly human pandemic. The so-called Spanish flu pandemic that broke out in 1918 is estimated to have killed from 20 million to 40 million people worldwide by the time it had run its course two years later.