Firfty serum and fifty semen samples collected from cattle and buffalo bulls were subjected to ELISA and gB gene based PCR, respectively to detect antibodies in serum and viral DNA in the semen against BHV 1. Out of 50 bulls, 15 (30%) serum samples were detected positive by ELISA while 21 (42%) semen samples were positive by gB gene based PCR. While correlating the results of ELISA and PCR, some seronegative bulls revealed presence of viral genome in semen whereas few seropositive bulls could not reveal viral genome in semen, thus, suggesting application of combined serological assay and PCR assay to detect the presence of BHV-1 infection in bulls.

The seroprevalence of Mycoplasma equigenitalium among indigenous equines was determined by an indirect ELISA. One thousand thirty nine sera samples from apparently healthy indigenous equines from seventeen States of the country were subjected to indirect ELISA. The overall seroprevalence in the country was found to be 5.96% with a range of 0% to 19.0% in different States of India (Haryana, 9.6%; Rajasthan, 7.2%; Uttaranchal, 2.0%, Karnataka, 2.3%; Punjab, 10.4%; Uttar Pradesh, 3.4%; Gujarat, 0%; Andhra Pradesh, 0%; Maharashtra, 2.9%; West Bengal, 0%; Tamil Nadu, 0%; Meghalaya, 19.0%; Jammu and Kashmir, 7.8%; Delhi, 0%; Himachal Pradesh, 5.5%; Bihar, 3.3%; Madhya Pradesh, 4.0%).

To develop ELISA to detect antibodies specific to Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis), the carboxyl termini of the 34 kDa proteins of M. paratuberculosis and Mycobacterium avium subsp. avium (M. avium) were expressed in Escherichia coli expression system. Antibodies specific to M. paratuberculosis were detected with the truncated 34 kDa protein of M. paratuberculosis in ELISA after pre-absorption of serum samples with the truncated 34 kDa protein of M. avium. All the serum samples from cattle confirmed to be infected with M. paratuberculosis were positive and those from healthy cattle were negative in the present ELISA system. These results indicate that the established ELISA detects antibodies specific to M. paratuberculosis with high specificity and sensitivity and is an useful tool for the screening of Johne's disease.