Indiana avian flu outbreak serves as biosecurity reminder for Pa. poultry owners

A new outbreak of highly pathogenic avian influenza confirmed this month in the state of Indiana serves as a warning to Pennsylvania poultry producers and small-flock owners that they ignore biosecurity measures at their own risk, according to a poultry specialist in Penn State's College of Agricultural Sciences.

U.S. Department of Agriculture officials announced Jan. 15 that a commercial turkey farm in Dubois County, Indiana, had tested positive for "high-path" H7N8 avian flu. This strain of the virus is not the same subtype that caused a massive outbreak last year in the West and Midwest, where more than 48 million birds -- mostly on commercial layer and turkey farms -- were lost.

The culprit in the 2015 outbreak was an H5N2 virus that originated in Asia and was thought to have been carried into North America by migrating waterfowl. The H7N8 virus discovered in Indiana, however, is a North American virus strain, noted Eva Wallner-Pendleton, senior research associate in the Department of Veterinary and Biomedical Sciences and avian pathologist in Penn State's Animal Diagnostic Laboratory.

"It appears that the high-path H7N8 outbreak on one turkey farm may have been the result of mutation of low pathogenicity H7N8 viruses that had been circulating on turkey farms in this region at least since Jan. 6, 2016, which is the last time the flocks had been tested," she said. "USDA is studying these viruses more fully through a procedure called 'sequencing,' but this is not an exotic foreign virus strain -- it's a North American virus that probably was circulating in wild birds earlier." 

The pathogenicity of a virus refers to its ability to produce disease. Wallner-Pendleton explained that any H5 or H7 virus has the capacity to mutate into a high-path virus if it goes from wild birds into domestic poultry species and has time to circulate. "Low-path AI viruses can go undiagnosed because they often produce very little illness or death. The time needed to mutate into high path viruses varies considerably from weeks to months, or it can occur rapidly."

She stressed that the H7N8 virus is not thought to be a threat to human health or food safety. According to USDA, no human infections associated with this subtype have been reported, and the proper handling and cooking of poultry and eggs to an internal temperature of 165 F kills bacteria and viruses, including avian flu.

Since the initial detection in Indiana, at least eight other nearby turkey farms have tested positive for low-path H7N8 avian flu. To prevent further spread, these premises are being depopulated, with a loss of more than 245,000 turkeys. In addition, a 156,000-chicken layer operation that tested negative also was depopulated due to "dangerous contact" that might have spread the virus. Another 100 Indiana farms have tested negative for avian flu.

"This outbreak serves to emphasize that good biosecurity is still needed for all flocks and that avian flu viruses do not need to be exported from outside North America," Wallner-Pendleton said. "Our waterfowl and shorebirds are natural carriers of domestic AI viruses that may pose a risk if allowed to enter domestic poultry flocks."

The Penn State Extension Poultry Team advises poultry owners to follow common-sense biosecurity practices that isolate their flocks from other birds. Particularly important is keeping poultry away from any possible contact with wild waterfowl (ducks, geese, swans) and shore birds (gulls, terns), their droppings and the water sources where these wild birds congregate.

For specific recommendations on biosecurity, how to recognize the symptoms of avian flu and how to report suspected cases, visit the Penn State Extension avian flu website.


Last Updated January 22, 2016