The highly pathogenic avian influenza (HPAI) outbreaks in poultry occurring this year in the United States are being driven by an unprecedented virus challenge in migratory wild fowl, said Dr. Mary J. Pantin-Jackwood, research veterinary medical officer, Southeast Poultry Research Laboratory.
In the webinar, “Avian influenza: Control efforts and trade impacts,” presented by WATT Global Media and sponsored by Zoetis, Pantin-Jackwood said the epidemiological challenge is worrisome because migratory wild birds are carrying and spreading highly pathogenic avian influenza virus, something which is relatively unusual.
“Usually high-path avian influenza is not moved by wild birds,” she said. “This outbreak is different in that migratory birds seem to be infected with [highly pathogenic avian influenza] viruses and do not show clinical signs but shed enough of the virus to transmit the disease [to commercial poultry]."
Unprecedented level of avian flu virus
When asked if the level of HPAI disease challenge in wild migratory birds is at an unprecedented high level, Pantin-Jackwood said, “Yes, definitely.”
Pantin-Jackwood said the disease situation is worrisome because of the virus circulating in the wild migratory birds, which cannot be eliminated.
“It is hoped that the wild birds will, eventually, mount an immune response to the virus which would mean their population would not become re-infected. But we don’t know what is going to happen."
Governmental authorities and the poultry industry are counting on summer heat to suppress the disease’s transmission. In the meantime, vaccines for the H5N2 avian flu strain are being readied in case virus outbreaks in poultry continue in the fall of 2015.
HPAI control measures
Pantin-Jackwood said federal and State partners as well as industry are responding quickly and decisively to these outbreaks by following these five basic steps:
1. Quarantine – restricting movement of poultry and poultry-moving equipment into and out of the control area;
2. Eradicate – humanely euthanizing the affected flock(s);
3. Monitor region – testing wild and domestic birds in a broad area around the quarantine area;
4. Disinfect – kill the virus in the affected flock locations; and
5. Test – confirming that the poultry farm is AI virus-free.
USDA also is working with its partners to actively look and test for the disease in commercial poultry operations, live bird markets and in migratory wild bird populations.
Mary J. Pantin-Jackwood is with the Exotic and Emerging Avian Viral Diseases Research Unit Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, Georgia.