The United States Department of Agriculture confirmed "the presence of highly pathogenic H5N2 avian influenza (HPAI) in a commercial turkey flock in Boone County, Arkansas".
The USDA added that "state officials quarantined the affected premises and birds on the property will be depopulated to prevent the spread of the disease.
Birds from the 40,200-strong turkey flock "will not enter the food system", the statement said, adding that officials deem "low… the risk to people from these HPAI H5 infections in wild birds, backyard flocks and commercial poultry".
'Could widen trading bans'
However, the discovery raised concerns over further curbs on US broiler exports, with countries such as Singapore and Taiwan already having curbed imports of poultry from some US states on grounds of bird flu outbreaks.
"This could widen US poultry trading bans," broker CHS Hedging said.
"Arkansas is the third largest US turkey-producing state, as well as the headquarters for Tyson Foods, the nation's largest chicken company."
Shares in poultry companies fell after US officials confirmed the discovery of a "highly pathogenic" bird flu strain in Arkansas.
Shares in Tyson Foods, the top US-based meat producer, stood 4.9% lower at $37.81 in afternoon deals in New York, where stock in Sanderson Farms, the third-ranked US poultry group, stood 5.8% lower at $77.71.
Shares in Pilgrim's Pride, the US poultry giant controlled by Brazil's JBS, stood 7.2% lower at $24.63.