Laboratory testing of samples from eight of nine southern Indiana turkey flocks was recently completed by the U.S. Department of Agriculture National Veterinary Services Laboratory in Ames, Iowa. While all nine were initially announced as H7 influenza-positive, the specific strain was yet to be determined. The Indiana State Board of Animal Health has been informed eight are low-pathogenic H7N8. Testing continues on the remaining sample.
Indiana state veterinarian Bret Marsh calls this good news, and evidence that Indiana's aggressive surveillance and response efforts in Dubois County are working.
"The low-path H7N8 virus was identified during testing in the 10-km zone around the initial flu-positive flock," Dr. Marsh said. "Because flu viruses are constantly mutating, we want to catch any case as early as possible after infection. We know this virus strain can intensify, so finding these cases as low-path strains shows we are keeping pace with the spread of this disease in the area."
In addition to the HxNx naming scheme for specific strains, AI viruses are further classified by their pathogenicity—the ability
of a particular virus strain to produce disease in domestic chickens. Highly pathogenic avian influenza (HPAI) virus strains are extremely infectious, often fatal to domestic poultry, and can spread rapidly from flock to flock. Low pathogenicity avian influenza (LPAI) virus strains occur naturally in wild migratory waterfowl and shorebirds without causing illness. LPAI viruses have the potential to mutate into HPAI.
"This finding does not alter the aggressive control strategy BOAH has set forth," added Marsh. "Nor does it change our resolve to eliminate this virus wherever we find it."