Low-Pathogenicity H7N2 Avian Influenza Outbreak in Virginia During 2002

Abstract

An outbreak of low-pathogenicity H7N2 avian influenza virus (AIV) in the Shenandoah Valley of Virginia during the spring and summer of 2002 affected 197 farms and resulted in the destruction of over 4.7 million birds. The outbreak affected primarily turkey farms (28 breeders, 125 grow out) with some spillover into chicken farms (29 breeders, 13 grow out, 2 table-egg layers). Although no direct link was established, the strain of H7N2 AIV in this outbreak had a molecular fingerprint that was essentially identical to the H7N2 AIV strain that has circulated in the live bird markets of the northeastern United States for the last 8 yr. After an initial delay caused by lack of viable disposal options, depopulation and disposal, primarily in sanitary landfills, was carried out within 24 hr of detection of a positive flock. Increased surveillance efforts included once-a-week testing of the daily mortality of all poultry farms in the region, testing of all breeder farms every 2 wk, and testing of all flocks prior to movement for any reason. A statistical sampling of backyard flocks and wild birds found no evidence of the virus. The successful eradication of this outbreak was the result of the efforts of a highly effective task force of industry, state, and federal personnel.

Development and Evaluation of an Influenza Virus Subtype H7N2 Vaccine Candidate for Pandemic Preparedness

“…The parent virus strain was isolated from an affected animal during the 2002 low-pathogenicity H7N2 avian influenza outbreak (1). A/TurkeyVirginia/4529/02 (TK/VA/02) was characterized by Immunology and Pathogenesis Branch, Influenza Division, CDC, Atlanta, GA.…”

“…Viruses of the H5 and H7 subtypes have caused outbreaks in commercial poultry in the Americas (1,7,11,16,17). These viruses constitute a lineage that is genetically and antigenically distinct from the European and Asian lineages which currently circulate in that hemisphere.…”

“…An outbreak of low-pathogenicity H7N2 avian influenza virus in turkey farms in Virginia resulted in the destruction of over 4.7 million birds (1). During this outbreak, one poultry worker reported a upper respiratory illness that was later found to be associated with H7N2 infection (4).…”

Identification of Type A Influenza Viruses from Wild Birds on the Delmarva Peninsula, 2007–10

“…In 1994, an H7N2 AIV of low pathogenicity was detected in the LBMs and has persisted since, despite efforts to eliminate the virus. Since 1996, the LBMs have been implicated as a source of H7N2 AIV in at least 5 outbreaks in commercial poultry in the Northeast United States (Akey 2003;Davison et al 2003;Dunn et al 2003, D. Senne unpublished observation).…”

Avian influenza control strategies in the United States of America

“…Regional biosecurity plans to co-ordinate movement of LPAI-recovered birds to slaughter; disposal of AIcontaminated manure and AI-infected carcasses, C&D of farms and repopulation have been developed and used in California and Minnesota with success (Halvorson 1998;Cardona 2003). In the Virginia H7N2 LPAI outbreak (2002), the movement of daily mortality off the farm to a rendering facility was associated with spread of avian influenza from farm to farm (Akey 2003). This necessitates finding alternative methods for disposal of daily mortality such as on-farm composting or implementation of revised biosecurity procedures to prevent rendering trucks from entering the farm.…”