Highly pathogenic avian influenza,
United States of America
Information received on 24/04/2020 from Dr Mark Davidson, Associate Administrator, USDA-APHIS, United States Department of Agriculture, Washington, United States of America
Report type Follow-up report No. 2
Date of start of the event 06/04/2020
Date of confirmation of the event 08/04/2020
Report date 24/04/2020
Date submitted to OIE 24/04/2020
Date event resolved 28/05/2020
Reason for notification Recurrence of a listed disease
Date of previous occurrence 11/08/2017
Manifestation of disease Clinical disease
Causal agent Highly pathogenic avian influenza virus
Serotype H7N3
Nature of diagnosis Laboratory (advanced)
This event pertains to a defined zone within the country
Related reports Immediate notification (09/04/2020)
Follow-up report No. 1 (16/04/2020)
Follow-up report No. 2 (24/04/2020)
Follow-up report No. 3 (30/04/2020)
Follow-up report No. 4 (07/05/2020)
Follow-up report No. 5 (15/05/2020)
Follow-up report No. 6 (21/05/2020)
Follow-up report No. 7 (05/06/2020)
Follow-up report No. 8 (05/08/2020)
Outbreaks There are no new outbreaks in this report
Source of the outbreak(s) or origin of infection
  • Unknown or inconclusive
Epidemiological comments 24 April 2020 update All control area and enhanced weekly surveillance testing have reported negative results since 8 April 2020. Routine passive and active surveillance for the National Poultry Improvement Plan (NPIP) avian influenza programs is ongoing state-wide in South Carolina. The USDA Animal Plant Health Inspection Service (APHIS) and South Carolina State Veterinarianís Office, part of Clemson University Livestock Poultry Health (CULPH), continue conducting a comprehensive epidemiological investigation and enhanced surveillance in the area. Based on sequencing information for all H7N3 North Carolina/South Carolina (NC/SC) cases, data supports a single virus introduction followed by secondary spread. Mutation of the low pathogenic avian influenza (LPAI) virus to highly pathogenic avian influenza (HPAI) occurred in one house on a single premises. Sequencing information also supports that H7N3 LPAI NC/SC viruses are: 1. distinct from other recent H7 events in poultry, and have not previously been detected in poultry 2. similar to other wild bird viruses, sharing a common HA ancestry with those from 2016-2018 3. North American wild bird-origin viruses 4. NOT related to the H7N3 HPAI event in Mexico nor the Anhui lineage H7N9 viruses
Control measures
Measures applied
  • Movement control inside the country
  • Surveillance outside containment and/or protection zone
  • Surveillance within containment and/or protection zone
  • Quarantine
  • Official disposal of carcasses, by-products and waste
  • Stamping out
  • Zoning
  • Vaccination prohibited
  • No treatment of affected animals
Measures to be applied
  • Disinfection
Future Reporting
The event is continuing. Weekly follow-up reports will be submitted.