Low pathogenic avian influenza (poultry) (H7N8),United States of America

Information received on 19/01/2016 from Dr John Clifford, Deputy Administrator, Animal and Plant Health Inspection Service, United States Department of Agriculture, Washington, United States of America

Summary

Report type	Immediate notification
Date of start of the event	16/01/2016
Date of confirmation of the event	16/01/2016
Report date	19/01/2016
Date submitted to OIE	19/01/2016
Reason for notification	Reoccurrence of a listed disease
Date of previous occurrence	2015
Manifestation of disease	Sub-clinical infection
Causal agent	Low pathogenic avian influenza virus
Serotype	H7N8
Nature of diagnosis	Laboratory (advanced)
This event pertains to	a defined zone within the country

New outbreaks

Summary of outbreaks

Total outbreaks: 8

Outbreak Location

INDIANA ( Dubois County 7, Dubois Dubois County 9, Dubois Dubois County 5, Dubois Dubois County 10, Dubois Dubois County 2, Dubois Dubois County 8, Dubois Dubois County 3, Dubois Dubois County 4, Dubois )

Total animals affected

Species	Susceptible	Cases	Deaths	Destroyed	Slaughtered
Birds	155405	**		143700	0

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

Unknown or inconclusive

Epidemiological comments

As part of existing avian influenza response plans, the USDA Animal and Plant Health Inspection Service (APHIS) in conjunction with the Indiana State Board of Animal Health, are conducting a comprehensive epidemiological investigation and enhanced surveillance and testing in the Indiana HPAI H7N8 control area. Enhanced surveillance in the control area for the HPAI H7N8 Indiana event identified low pathogenic avian influenza (LPAI) H7N8 in 8 turkey flocks. The partial sequences of the LPAI and HPAI H7N8 viruses are nearly identical except for the HA gene insertion which imparts high pathogenicity to the HPAI virus. While the detection of AI in these additional flocks was of low pathogenicity, and the turkeys in these flocks were clinically healthy, this virus has a potential to mutate to HPAI, and, therefore, appropriate sanitary measures are being implemented to mitigate the risk.
State officials have quarantined the affected premises and implemented movement controls. Depopulation of birds on the premises is under way.

Control measures

Measures applied	Movement control inside the country Quarantine Surveillance outside containment and/or protection zone Stamping out Surveillance within containment and/or protection zone Zoning Vaccination prohibited No treatment of affected animals
Measures to be applied	Disinfection / Disinfestation Official disposal of carcasses, by-products and waste

Diagnostic test results

Laboratory name and type

National Veterinary Services Laboratories (NVSL) ( National laboratory )

Tests and results

Species	Test	Test date	Result
Birds	real-time reverse transcriptase/polymerase chain reaction (RRT-PCR)	16/01/2016	Positive
Birds	virus isolation