Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2006 Jan 1;42(1):14-20.
doi: 10.1086/498977. Epub 2005 Nov 22.

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

Kendall P Myers  1 , Christopher W Olsen, Sharon F Setterquist, Ana W Capuano, Kelley J Donham, Eileen L Thacker, James A Merchant, Gregory C Gray
Affiliations

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

Kendall P Myers et al. Clin Infect Dis. .

Abstract

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.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Trends in hog operations in the United States. Adapted from [23].
See this image and copyright information in PMC

References

    1. Webster RG, Sharp GB, Claas EC. Interspecies transmission of influenza viruses. Am J Respir Crit Care Med. 1995;152:S25–30. - PubMed
    1. Reid AH, Taubenberger JK. The origin of the 1918 pandemic influenza virus: a continuing enigma. J Gen Virol. 2003;84:2285–92. - PubMed
    1. Kimura K, Adlakha A, Simon PM. Fatal case of swine influenza virus in an immunocompetent host. Mayo Clin Proc. 1998;73:243–5. - PubMed
    1. Dacso CC, Couch RB, Six HR, Young JF, Quarles JM, Kasel JA. Sporadic occurrence of zoonotic swine influenza virus infections. J Clin Microbiol. 1984;20:833–5. - PMC - PubMed
    1. de Jong JC, Paccaud MF, de Ronde-Verloop FM, et al. Isolation of swine-like influenza A(H1N1) viruses from man in Switzerland and The Netherlands. Ann Inst Pasteur Virol. 1988;139:429–37. - PubMed

Publication types

MeSH terms

Substances