The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) issued a press release on Sunday to confirm highly pathogenic avian influenza was found in a commercial chicken breeder’s flock in Lincoln County, Tennessee.
The 73,500-bird flock experienced an increased number of deaths, raising a red flag and leading to laboratory testing that revealed the infection. Tennessee’s Kord Animal Health Diagnostic Laboratory completed initial testing, and the APHIS National Veterinary Services Laboratories in Iowa confirmed the results. While the isolation of the subtype of virus is not yet complete, it is expected to be the neuraminidase protein, or “N-type.” The USDA characterizes the differences among subtypes as follows:
AI viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1–H16), and neuraminidase or “N” proteins, of which there are 9 (N1–N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype, and can be further broken down into different strains. AI viruses are further classified by their pathogenicity (low or high)— the ability of a particular virus strain to produce disease in domestic chickens.
The Tennessee Department of Agriculture is already working to ensure facility workers “are taking the proper precautions to prevent illness and contain disease spread.” They have also quarantined the facility and will destroy the animals to prevent further spread. The flock will not be used as food.
According to the USDA, wild birds can carry the illness without appearing sick and transmit it to other bird populations they encounter. Since there are large chicken-producing facilities in surrounding states, state and local officials are working together to surveil and test nearby commercial facilities, live bird markets, and migratory birds in order to prevent a similar outbreak to that of 2015, which killed more than 48 million birds after the virus spread through equipment, employees, and other animals:
The virus was introduced into the U.S. by wild migratory waterfowl and then spread from farm to farm in a number of ways. This included farms sharing equipment, vehicles moving between farms without being cleaned or disinfected, employees moving between infected and non-infected farms, rodents and small wild birds reported inside some poultry houses, and feed stored outside or without appropriate biosecurity measures. The virus spread was also assisted by instances of noncompliance with industry-recommended biosecurity practices.
So far there is no evidence that other facilities or populations have been infected.
Citizens are urged to report sick birds or unusual bird deaths to their state officials, or to the USDA at 1-866-536-7593.
Update 3/7/17 4:18 am EST:
According to Reuters, Asian countries are now reacting to the news by limiting imports of poultry:
South Korea will ban imports of U.S. poultry and eggs after a strain of H7 bird flu virus was confirmed on Sunday at a chicken farm in Tennessee, South Korea’s agriculture ministry said.
Japan and Taiwan will block poultry from the state, while Hong Kong will restrict imports from the Tennessee county where the infected flock was located, said James Sumner, president of the USA Poultry & Egg Export Council, a trade group.