Are swine workers in the United States at increased risk of infection with zoonotic influenza virus?


Journal Article

BACKGROUND: Pandemic influenza strains originate in nonhuman species. Pigs have an important role in interspecies transmission of the virus. We examined multiple swine-exposed human populations in the nation's number 1 swine-producing state for evidence of previous swine influenza virus infection. METHODS: We performed controlled, cross-sectional seroprevalence studies among 111 farmers, 97 meat processing workers, 65 veterinarians, and 79 control subjects using serum samples collected during the period of 2002-2004. Serum samples were tested using a hemagglutination inhibition assay against the following 6 influenza A virus isolates collected recently from pigs and humans: A/Swine/WI/238/97 (H1N1), A/Swine/WI/R33F/01 (H1N2), A/Swine/Minnesota/593/99 (H3N2), A/New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2), and A/Nanchang/933/95 (H3N2). RESULTS: Using multivariable proportional odds modeling, all 3 exposed study groups demonstrated markedly elevated titers against the H1N1 and H1N2 swine influenza virus isolates, compared with control subjects. Farmers had the strongest indication of exposure to swine H1N1 virus infection (odds ratio [OR], 35.3; 95% confidence interval [CI], 7.7-161.8), followed by veterinarians (OR, 17.8; 95% CI, 3.8-82.7), and meat processing workers (OR, 6.5; 95% CI, 1.4-29.5). Similarly, farmers had the highest odds for exposure to swine H1N2 virus (OR, 13.8; 95% CI, 5.4-35.4), followed by veterinarians (OR, 9.5; 95% CI, 3.6-24.6) and meat processing workers (OR, 2.7; 95% CI, 1.1-6.7). CONCLUSIONS: Occupational exposure to pigs greatly increases workers' risk of swine influenza virus infection. Swine workers should be included in pandemic surveillance and in antiviral and immunization strategies.

Full Text

Duke Authors

Cited Authors

  • Myers, KP; Olsen, CW; Setterquist, SF; Capuano, AW; Donham, KJ; Thacker, EL; Merchant, JA; Gray, GC

Published Date

  • January 1, 2006

Published In

Volume / Issue

  • 42 / 1

Start / End Page

  • 14 - 20

PubMed ID

  • 16323086

Pubmed Central ID

  • 16323086

Electronic International Standard Serial Number (EISSN)

  • 1537-6591

Digital Object Identifier (DOI)

  • 10.1086/498977


  • eng

Conference Location

  • United States