Comparison of newly standardized ‘Latex milk agglutination test’, with ‘Indigenous milk ELISA’ for ‘on spot’ screening of domestic livestock against <i>Mycobacterium avium </i> subsp.<i> paratuberculosis</i> infection

Abstract

511-517Mycobacterium avium subspecies paratuberculosis (MAP), the cause of Johne’s disease in animals, has also been associated with Crohn’s disease (CD), Inflammatory bowel disease (IBD) and auto-immune disorders of humans. Increased consumption of milk and milk products made from pasteurized milk led to the sharp rise in the cases of IBD/CD in India. Milk and milk products are the main source of transmission of MAP from animals to humans, since MAP is not inactivated during pasteurization. Lack of rapid and sensitive ‘field test’ is the major stumbling block in estimating bio-incidence of MAP and threat it poses to human population. In the present study, newly standardized ‘Latex milk agglutination test’ (LMAT) was compared with ‘Indigenous milk ELISA’ test. Of the 900 raw milk samples of domestic livestock screened, 36.4 and 51.4% were positive in milk ELISA and LMAT, respectively. In milk ELISA, 38.7, 71.4, 35.1 and 33.5% milk samples of goats, sheep, cattle and buffaloes were positive for MAP, respectively. Whereas in LMAT, 60.6, 90.4, 45.9 and 44.7% milk samples of goats, sheep, cattle and buffaloes were positive for MAP, respectively. LMAT had 70.5% overall rate of agreement with milk ELISA. LMAT had sensitivity and specificity of 80.1 and 65.0%, respectively on comparion with ‘Indigenous milk ELISA’ and Kappa value of 0.416. Strength of agreement between two tests was ‘fair’. Study showed that LMAT has potential to be developed as field based ‘spot test’ for the rapid screening of milk samples of lactating domestic livestock for the detection of MAP