Final report on resolution of Avian Influenza (H7N3) in North and South Carolina

July 24, 2020

5 Jun 2020 All environmental sampling and testing for AI virus post C & D completion were negative for avian influenza virus at the infected South Carolina premises. The premises was released from quarantine on 28 May 2020. Control area had been released on May 6 after 4 rounds of area testing.
May 30 The one positive premises in South Carolina was released from quarantine. Cleaning and disinfection were completed as of 7 May.
April 10 USDA-APHIS confirmed HPAI H7N3 in a turkey breeder flock in South Carolina on same premises where LPAI was detected in late March.

April 10 USDA-APHIS confirmed the presence of highly pathogenic H7N3 avian influenza (HPAI) in a commercial turkey flock in Chesterfield County, South Carolina on the same premises infected with low pathogenic (LPAI)Avian Influenza H7N3, suggesting a mutation of the virus strain has occurred.

March 13 - As part of routine surveillance for H5/H7 Avian Influenza, H7N3 low pathogenic AI (LPAI) was detected in a turkey parent and 2 grow-out flocks in Union and Anson counties, North Carolina.
March 24 to April 6 - LPAI H7N3 identified at 3 premises in North Carolina and 1 premises in South Carolina. H7 LPAI was subsequently confirmed in 1 commercial turkey breeder and 4 other turkey meat flocks in North Carolina. All 12 flocks (310,269 birds) have been destroyed and disposal is ongoing.
The most likely source of the LPAI is migratory waterfowl with inter-farm spread from possible defects in biosecurity. The Atlantic flyway extends from Georgia along east coast and over to southern Ontario and Quebec. High path versions of this virus strain caused outbreaks in BC 2004, a case in Sask. 2007 as well as Mexico 2012-2018. HPAI was last detected in the U.S. in 2017.