Swine trichinellosis in slaughterhouses of the metropolitan area of Toluca.

In order to determine the prevalence of Trichinella spiralis infections in abattoirs of the metropolitan area of Toluca where pigs from commercial farms as well as backyard pigs are slaughtered, 539 swine diaphragm tissue samples were collected and examined by trichinoscopy and artificial digestion. Serum samples from the same animals were analyzed by ELISA using somatic and excretory/secretory antigens, and by Western blot analysis. T. spiralis muscle larvae were not found by trichinoscopy or artificial digestion. However, specific antibodies were detected by ELISA and confirmed by Western blotting in 12.4% of the serum samples examined. Analysis of risk factors showed no association of seropositive results with sex. However, significant higher risk was observed in swine seven to 12 months old and in backyard pigs, compared with pigs from commercial farms.