Avian influenza H5N1 clade 18.104.22.168. emerges
Aug. 31, 2011
by Bryan Salvage
PARIS – The World Organization for Animal Health (OIE), which closely follows the evolution of avian influenza in domestic and wild birds globally, acknowledges the recent identification of an H5N1 virus described as clade 22.214.171.124. Small genetic changes are known to routinely occur in influenza A viruses, including those that may affect humans or animals. The emergence of the H5N1 virus, such as clade 126.96.36.199, is one of such genetic mutations taking place as part of the natural evolution of the virus.
OIE relays there is not an immediate cause for alarm, but as the case with the emergence of any new strain – it reinforces the need for sustained monitoring of viruses in animal populations so changes in viruses circulating in the field are detected at an earliest stage and that most appropriate disease control strategies are chosen to best protect animal and public health.
OIE recommends countries maintain active surveillance in bird populations and encourages national veterinary services to be prepared to quickly report and respond to unusual animal disease events that may represent more serious disease in animals or that may pose increased risk to humans.
Avian influenza vaccines need to be regularly tested to check whether they effectively combat the viruses circulating in the field, as is the case with human influenza vaccines whose composition needs to be reviewed every year. OIE reference laboratories and other partner labs are involved in ongoing surveillance and development of good quality vaccines that match any viruses of concern.
The OIE reference lab in Harbin, China, has developed a new vaccine seed strain that experimentally protects poultry from the identified H5N1 virus clade 188.8.131.52. This vaccine, once available for field use, will be used in countries where H5N1 virus clade 184.108.40.206 has been identified. Registration and manufacturing of a poultry vaccine with the new seed strain is underway.
OIE and OFFLU’s guidance on early detection and rapid response to animal disease events prove crucial in preventing and controlling animal influenzas, with positive implications for human health. OFFLU is a joint OIE/FAO worldwide network of expertise on avian influenza. It also provides animal influenza data to the World Health Organization regularly to assist with the selection of candidate influenza vaccines for humans.