Standardisation of A Coproantigen Sandwich Elisa for Early Immunodiagnosis Ofamphistomosis in Cattle

Paramphistomosis is a snail borne trematode disease in ruminants with widespread geographical distribution in tropical and subtropical areas. Even though the disease is highly prevalent causing high morbidity and mortality in young stock it has been neglected in adult animals which results in significant economic losses. Considering the economic importance of bovine amphistomosis, and the lack of sensitive and specific diagnostic tools to detect the pathogenic prepatent stage, the present study aimed in standardization of sandwich ELISA for the early diagnosis of bovine amphistomosis by coproantigen detection. A coproantigen sandwich ELISA protocol was standardised using guinea pig and rabbit hyperimmune serum which could detect minimum 3 ng/µl of excretory-secretory antigen in dung. Dot ELISA was also standardised as a rapid test for coproantigen detection in amphistomosis. Out of 515 faecal samples collected from six agro-ecological zones of central Kerala, 362 (70%) were found to be positive by sandwich ELISA as against 165 (32%) by ova detection. Sandwich ELISA gave 100 per cent positive result as in microscopy whereas Dot ELISA gave positive results in only 76 per cent samples. No false positive results were obtained in known negatives by both the tests. Sandwich ELISA was found to be superior with 90 per cent sensitivity, 100 per cent specificity, 100 per cent positive predictive value (PPV), 80 per cent negative predictive value (NPV) whereas Dot ELISA had 76 per cent sensitivity, 100 per cent specificity, 100 per cent PPV and 62.5 per cent NPV with 83 per cent accuracy. This forms the first report of coproantigen sandwich ELISA being used in the diagnosis of bovine amphistomosis. This study concludes that coproantigen sandwich ELISA with its considerably high performance values in respect of sensitivity, specificity and accuracy could be developed as a reliable tool for early diagnosis of bovine amphistomosis.