8 of 9 farms found to have different, low-pathogenic, strain

Laboratory tests completed by the U.S. Department of Agriculture (USDA) National Veterinary Services Laboratory in Ames, Iowa have determined eight of the nine samples have been found to be low-pathogenic H7N8.

The original virus located on the Kalb farm was the high-pathogenic form of the H7N8 virus which is typically fatal for infected poultry. The low-pathogenic is not normally fatal, according to the USDA.

While all nine were announced as H7 influenza-positive yesterday, the specific strain was undetermined. Testing continues on the remaining sample.

Indiana State Veterinarian Bret D. Marsh, DVM 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 Dr. Marsh. “Nor does it change our resolve to eliminate this virus wherever we find it.”

Priority response by the state of Indiana and USDA continues on all the infected farms. Turkeys are being humanely euthanized on infected sites within 24 hours of diagnosis. Depopulation eliminates the source of infection to prevent the disease from spreading. Disposal of the turkeys, primarily via indoor composting, will be followed by thorough cleaning and disinfection of all barns.

Officials are in the process of depopulating 240,900 turkeys so far.

Aggressive testing of other poultry farms in the area continues. During the last 24 hours, commercial farms have yielded 100 negative flu tests, beyond the nine new positives. In addition, state and federal teams have visited 503 residences in the area to identify any small flocks for testing. Tests are pending on 17 small flocks. Residential visits will continue in the 10-km area.

Avian influenza does not present a food safety risk; poultry and eggs are safe to eat. The Centers for Disease Control and Prevention (CDC) considers the risk of illness to humans to be very low.