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Volume 19, Number 6—June 2013


Active Surveillance for Influenza A Virus among Swine, Midwestern United States, 2009–2011

Cesar A. Corzo, Marie CulhaneComments to Author , Kevin Juleen, Evelyn Stigger-Rosser, Mariette F. Ducatez, Richard J. Webby, and James F. Lowe
Author affiliations: University of Minnesota, Saint Paul, Minnesota, USA (C.A. Corzo, M. Culhane, K. Juleen); St. Jude Children’s Research Hospital, Memphis, Tennessee, USA (E. Stigger-Rosser, M.F. Ducatez, R.J. Webby); Carthage Veterinary Services, Carthage, Illinois, USA (J.F. Lowe)

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Table 3

Relationship between group influenza status with age and season in growing pigs tested for influenza virus, midwestern United States, June 2009–December 2011*

Odds ratio (95% CI)
p value
Fall (referent) NA NA NA
Spring 0.741 2.0 (1.1– 3.8) 0.01
Summer 0.657 1.9 (1.0–3.5) 0.03
Winter –0.072 0.9 (0.4–1.8) 0.83
Age –0.041 0.9 (0.9–1.0) 0.09

*Repeated measures logistic regression multivariable analysis. Generalized χ2 divided by degrees of freedom = 0.92. NA, not applicable.

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