Seroepidemiology of Leptospira Infection in Backyard Pigs in Durango State, Mexico

This study aimed to determine the seroprevalence and correlates of Leptospira IgG antibodies in backyard pigs in the northern Mexican state of Durango. We performed a cross-sectional study of 305 backyard pigs. Anti-Leptospira IgG antibodies were detected using microscopic agglutination assay (MAT) with a panel of 12 Leptospira antigens.

Overall, antibodies against Leptospira (any of the 12 Leptospira serovars examined) were found in 186 (61.0%) of the 305 pigs studied. Seropositive pigs were found on 80 (70.2%) of the 114 properties surveyed. The predominant serovar was Leptospira interrogans Pomona (n = 55); followed by Leptospira noguchii Lousiana and Leptospira santarosai Tarassovi (n = 53 each); L. interrogans Bataviae (n = 47); Leptospira biflexa Semaranga and L. interrogans Hebdomadis (n = 36 each); L. interrogans Pyrogenes (n = 30); L. interrogans Djasiman (n = 20); Leptospira borgpetersenii Ballum (n = 11); L. noguchii Panama and L. interrogans Canicola (n = 5 each); and L. borgpetersenii Mini (n = 2). Logistic regression showed that seropositivity was associated with low (<1000 m above sea level) altitude (odds ratio [OR] = 3.24; 95% confidence interval [CI]: 2.01-5.20; P < 0.001).

This is the first report of Leptospira exposure in backyard pigs in Mexico and of an association between Leptospira exposure in pigs and altitude. Backyard pigs represent a high-risk group for Leptospira exposure.