Highly pathogenic avian influenza,
United States of America
Information received on 13/02/2015 from Dr John Clifford, Official Delegate, Chief Trade Advisor, Animal and Plant Health Inspection Service, United States Department of Agriculture, Washington, United States of America
Summary
Report type Follow-up report No. 7
Date of start of the event 10/12/2014
Date of confirmation of the event 14/12/2014
Report date 13/02/2015
Date submitted to OIE 13/02/2015
Date event resolved 22/07/2015
Reason for notification Recurrence of a listed disease
Date of previous occurrence 2004
Manifestation of disease Clinical disease
Causal agent Highly pathogenic avian influenza
Serotype H5N8
Nature of diagnosis Laboratory (advanced)
This event pertains to a defined zone within the country
Related reports Immediate notification (16/12/2014)
Follow-up report No. 1 (19/12/2014)
Follow-up report No. 2 (29/12/2014)
Follow-up report No. 3 (07/01/2015)
Follow-up report No. 4 (22/01/2015)
Follow-up report No. 5 (25/01/2015)
Follow-up report No. 6 (03/02/2015)
Follow-up report No. 7 (13/02/2015)
Follow-up report No. 8 (25/02/2015)
Follow-up report No. 9 (05/03/2015)
Follow-up report No. 10 (20/03/2015)
Follow-up report No. 11 (31/03/2015)
Follow-up report No. 12 (22/04/2015)
Follow-up report No. 13 (21/05/2015)
Follow-up report No. 14 (09/06/2015)
Follow-up report No. 15 (16/06/2015)
Follow-up report No. 16 (22/07/2015)
Follow-up report No. 17 (17/08/2015)
New outbreaks (1)
Outbreak 1 Kings County, Kings, CALIFORNIA
Date of start of the outbreak 02/02/2015
Outbreak status Resolved (20/03/2015)
Epidemiological unit Farm
Affected animals
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Birds 114000 114000
Affected population A commercial chicken and duck operation.
Summary of outbreaks Total outbreaks: 1
Total animals affected
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Birds 114000 ** 114000
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Birds ** ** ** **
*Removed from the susceptible population through death, destruction and/or slaughter
**Not calculated because of missing information
Epidemiology
Source of the outbreak(s) or origin of infection
  • Contact with wild species
Epidemiological comments The USDA Animal and Plant Health Inspection Service (APHIS), in conjunction with 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 2.3.4.4) 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 2.3.4.4 viruses are highly pathogenic for poultry. On 12 February 2015, the USDA APHIS National Veterinary Services Laboratories (NVSL) confirmed HPAI EA H5N8 virus in a 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 >99% 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.
Control measures
Measures applied
  • Movement control inside the country
  • Disinfection / Disinfestation
  • Quarantine
  • Stamping out
  • Zoning
  • Vaccination prohibited
  • No treatment of affected animals
Measures to be applied
  • No other measures
Diagnostic test results
Laboratory name and type Species Test Test date Result
National Veterinary Services Laboratories (NVSL) (National laboratory) Birds real-time reverse transcriptase/polymerase chain reaction (RRT-PCR) 12/02/2015 Positive
National Veterinary Services Laboratories (NVSL) (National laboratory) Birds virus sequencing 12/02/2015 Positive
Future Reporting
The event is continuing. Weekly follow-up reports will be submitted.
Map of outbreak locations