According to a statutory submission to the World Organization for Animal Health (OIE), Dr. Mark Davidson, Associate Administrator of the USDA-APHIS reported additional cases of H7N3 low pathogenicity avian influenza in asymptomatic turkey flocks on March 24th. The diagnoses were obtained as a result of surveillance implemented in the infected zone following recognition of the initial cases involving a parent flock and two grow-out flocks in Anson and Union Counties in North Carolina on March 13th.

The provisional diagnoses were confirmed by the National Veterinary Service Laboratory in Ames, IA. applying RRT-PCR followed by sequencing on samples processed on March 17th, 21st and 23rd.

As of March 24th eight flocks totaling 186,000 turkeys have been depleted with a range in farm population of 11,000 to 45,000. In addition to the two North Carolina counties a single flock of 36,000 turkeys in Chesterfield County, South Carolina was identified as being infected.

It is presumed that epidemiologic studies are in progress to determine the source of the H7N3 LPAI infection. The most likely presumption is introduction by migratory waterfowl with inter-farm dissemination attributed to possible defects in biosecurity. If this is the case to be determined by wildlife surveys then it may be assumed that the virus is being shed by birds transiting the Atlantic Flyway. This corridor has not been previously involved in outbreaks among commercial flocks. If proven the presence of either an H5 or H7 AIV, irrespective of current pathogenicity has implications for egg production, broiler breeder, broiler and turkey flocks extending from Georgia to the Eastern Shore. It remains to be seen whether this episode is a replay of the contained 2014 outbreak among turkey flocks in Northern California and the 2016 outbreak among turkey flocks in Indiana or assumes the proportions of a more serious outbreak as in Minnesota and the Dakotas in 2015. Given sufficient time and a large commercial population exposed, H5 and H7 AI viruses invariably mutate to high pathogenicity.

According to the USAPEEC exports should not be adversely affected by this as yet isolated and controlled cluster since importing nations are applying regionalization, restricting embargos to counties.