Mycobacterium avium subsp. paratuberculosis detection in individual and bulk tank milk samples from bovine herds and caprine flocks.

Paratuberculosis, or Johne's disease, is caused by Mycobacterium avium subsp. paratuberculosis (Map), and it generates great economic losses for the dairy industry worldwide. In humans, Map has been associated with Crohn's disease. Mexico has unknown paratuberculosis prevalence, and yet, control programs have not been applied. This study aimed to determine the presence of Map in milk samples from seropositive goats and cows and bulk tank milk samples from herds previously designated Map-infected using indirect enzyme-linked immunosorbent assay. Map DNA was detected in 100% of the bulk tank milk samples of 14 bovine herds and 3 caprine flocks using a modified insertion sequence 900 polymerase chain reaction (PCR). Additionally, Map DNA was detected in 100% of the individual milk samples from 10 cows and 8 goats. Further, based on the findings of the experimental insertion sequence 900 PCR assessment, evaluation of bulk tank and individual milk samples through a type-specific PCR was performed, which confirmed our previous findings and revealed that 56.25% cow and 63.63% goat milk had concurrent infections of the C, I, and S types. Out of 14 bulk tank milk samples, 10 had viable mycobacteria. Paratuberculosis was detected at a high frequency in cow and goat milk, which suggests that raw milk ingestion represents a potential risk of Map infection.