US - A commercial poultry flock in California has tested positive for the H5N8 subtype of the highly pathogenic avian influenza virus following higher-than-usual mortalities among chickens.
The World Organisation for Animal Health (OIE) received Follow-up Report No.7 dated 13 February from the USDA Animal and Plant Health Inspection Service (APHIS).
The farm was hit by the outbreak on 2 February. It is located in Kings County, California and is a commercial chicken and duck operation with 114,000 birds.
According to the report, APHIS and State Departments of Agriculture and Wildlife are continuing to conduct a comprehensive epidemiological investigation and enhanced surveillance (including wild bird surveillance of hunter harvested birds) in response to the HPAI H5N8 and H5N2 wild bird-related events.
Novel avian influenza virus of Eurasian origin (EA-H5N8 clade 18.104.22.168) spread rapidly along wild bird migratory pathways during 2014. Introduction of this EA-H5N8 virus into the Pacific Flyway sometime during 2014 has allowed mixing with North American (AM) lineage viruses and generated new combinations with genes from both EA and AM origin (or “reassortant” viruses) such as the EA/AM H5N2-reassortant detected in Canada and the US. These findings are not unexpected as the EA-H5N8 virus continues to circulate. The EA H5 clade 22.214.171.124 viruses are highly pathogenic for poultry.
On 12 February 2015, the USDA APHIS National Veterinary Services Laboratories (NVSL) confirmed HPAI EA H5N8 virus in this commercial chicken and duck flock in Kings County, California. The flock was experiencing an increase in chicken mortality.
The detection of the HPAI H5N8 in the commercial chicken and duck flock is related to the recent avian influenza events in wild birds. The partial HA/NA sequence is more than 99 per cent similar to A/gyrfalcon/WA/41088-6/2014 HPAI EA H5N8 based upon direct sequence attempt from chicken swab specimen. The premises has been quarantined.
Comprehensive epidemiological investigation and enhanced surveillance on the affected premises and in the area is being conducted.
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ThePoultrySite News Desk