The occurrence of paratuberculosis in the Indian ruminant population has been reported since early 1930s, which has been mainly based on the skin johnin test, faecal smear examination and at times pathology and serology. The objective of this study was to know the seroprevalence of paratuberculosis in selected population of ruminants from different part of India using a highly specific commercial ELISA kit (Institut Pourquier, France). The sensitivity of assay was tested on sera from naturally infected and serial sera from experimentally infected goats and sheep. All these animals were confirmed to be positive on the basis of bacterial culture and/ or histopathology. The sensitivity on experimental sera was 56% (28/50) whereas on natural sera, it was 73.3% (22/30). The naturally infected animals were mostly in the clinical stages, whereas experimentally infected animals had moderate and severe infection of paratuberculosis. The overall sensitivity was found to be 62.5%. The specificity of the assay was about 98% based on 98 sheep and goat sera from slaughterhouse, whose MLN tissue samples were negative on bacterial culture.

A total of 1822 sera from large and small ruminant population were screened by the ELISA and found to be positive in 22.45%, 20%, 11.6% and 4% of 414 indigenous cattle, 264 cross- bred cattle, 465 sheep and 359 goats, respectively. Cattle sera originated from central-west, northern and southern part of India, and sheep and goat sera were from organised farm of Rajasthan and Uttar Pradesh states of India, respectively. A total of 320 buffalo sera from central west (n= 80) and northern (n= 240) part of India did not show antibody prevalence. Though incidence of paratuberculosis has been reported in buffaloes, this ELISA kit has not been evaluated on buffalo sera in India. It was concluded that paratuberculosis was prevalent in many parts of India.