Slaughterhouse prevalence of ovine paratuberculosis in Southern India

Ovine paratuberculosis is a threat to small animal holders in terms of economic loss such as reduced growth performance and early culling. In order to study the slaughterhouse prevalence of ovine paratuberculosis, the slaughterhouse sheep samples (which are poor in body condition) collected over a period of two and half years from 1,034 suspected male sheep (poor in body condition) and 40 normal sheep (good body condition and subsequently negative by all the diagnostic tests employed) aged between 16 and 18 months were slaughtered at various abattoirs of Tamil Nadu. All the sheep taken in this study were maintained in almost same management conditions. DNA was extracted from 1,034 intestinal tissue and mesenteric lymph node and 121 were positive by IS 900 PCR. One hundred ten and 56 were positive by absorbed ELISA and Ziehl–Neelsen staining, respectively. In histopathology, 28 animals showed gross lesions of paratuberculosis infection (20—multibacillary and 8—paucibacillary forms). Out of 1,034 sheep tissues cultured, 32 showed cultural growth in Middlebrook 7H9 and 26 in Herrold's egg yolk medium. None of the 40 normal sheep were positive by any of the tests employed. In general, the mean body weight of paratuberculosis-affected animal either by any one of the tests employed was less than the non-affected sheep. The approximate economic loss per sheep/farmer/year is around Rs 1,840 (US$ 38.33) in paratuberculosis-affected sheep.