Recombinant LipL32 and LipL41 outer membrane proteins of Leptospira interrogans serovar Canicola were produced, and used as a pooled antigen in enzyme-linked immunosorbent assay (ELISA) to detect leptospiral antibodies in bovine sera samples. The optimum concentration of the pooled antigen was found to be 50ng of each antigen per well by using known positive and negative cattle sera. Using a total of 500 bovine sera samples the sensitivity, specificity and accuracy of pooled antigen based ELISA as compared to microscopic agglutination test (MAT) were 100%, 88.1% and 91.6%, respectively. The results suggested that antigen in ELISA could be preferred for detection of all those cases, which might have remained undiagnosed by performing MAT.

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%).

Outer membrane proteins (OMPs) of Pasteurella multocida strain P52 were purified by immunoaffinity chromatography (IAC) using pre-challenge serum from HS vaccinated cattle-calves. IgG antibody titers of pre-challenge sera from HS vaccinated calves surviving and succumbing to direct challenge with virulent culture were determined against formalized P52 cells, P52 crude cell lysate, and OMPs of P52 purified by IAC. It was observed that OMP antigens were involved with protective response in calves and indirect ELISA test using lAC purified antigens can be developed for in vitro potency determination of Haemorrhagic septicemia (HS) vaccines.