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Second case of highly pathogenic avian influenza confirmed in Tennessee

Boyd Barker/Tennessee Department of Agriculture 031717AvianInfluenzaTestingTN
An employee readies a sample for analysis to determine if highly pathogenic avian influenza is present.
It's within 2 miles of first case; depopulation has begun.

A second case of highly pathogenic avian influenza has been confirmed on a Tennessee chicken farm.

The case was found in a commercial chicken breeder flock within the existing controlled quarantined zone in Lincoln County, Tennessee.

This H7N9 strain is of North American wild bird lineage and is the same strain of avian influenza that was previously confirmed in Tennessee. It is not the same as the China H7N9 virus that has impacted poultry and infected humans in Asia. The flock of 55,000 chickens is located in the Mississippi flyway, within two miles of the first Tennessee case.

“Wild birds can carry this strain of avian influenza," said Tennessee State Veterinarian Dr. Charles Hatcher. “Given the close proximity of the two premises, this is not unexpected. We will continue to execute our plan, working quickly to prevent the virus from spreading further.”

Samples were taken from the affected flock on March 14 and the confirmation came on March 16. The samples were tested at Tennessee’s Kord Animal Health Diagnostic Laboratory and confirmed at the APHIS National Veterinary Services Laboratories (NVSL) in Ames, Iowa. The affected flock displayed signs of illness and experienced increased mortality.

Depopulation of the site has begun and federal and state partners will conduct surveillance and testing of commercial and backyard poultry within a 6.2 mile radius of the site.

No food supply risk

On March 4, the first confirmed detection of H7N9 HPAI occurred in a commercial poultry flock in Lincoln County. On March 8, a commercial poultry flock in Giles County tested positive for H7N9 low pathogenic avian influenza (LPAI).

The primary difference between LPAI and HPAI is mortality rate in domesticated poultry. A slight change to the viral structure can make a virus deadly for birds. Avian influenza virus strains often occur naturally in wild migratory birds without causing illness in those birds. With LPAI, domesticated chickens and turkeys may show little or no signs of illness. However, HPAI is often fatal for domesticated poultry.

Due to the contagious nature of avian influenza and its threat to domesticated poultry, the best way to contain the virus is to depopulate affected flocks and then disinfect affected premises.

Neither HPAI nor LPAI pose a risk to the food supply. No affected animals entered the food chain.

The risk of a human becoming ill with avian influenza during poultry illness incidents is very low.

State and federal officials continue to monitor and test poultry located in the areas immediately surrounding the three affected premises. No other flocks have shown signs of illness.

For more information

Sources: Tennessee Department of Agriculture, USDA APHIS

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