Molecular Epidemiological and Pathological Studies on Paratuberculosis in Cattle and Buffaloes

Abstract

Bovine Paratuberculosis is a chronic disease primarily of the gastrointestinal tract. The disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP). There was limited information available about this disease in the country and there was need to have an understanding about the magnitude and pathology of disease under local conditions. The study was planned to measure the Paratuberculosis prevalence in cattle and buffaloes at twelve government livestock farms , two cattle/buffalo colonies and the slaughterhouse of Faisalabad. A total of 2181 animals from twelve livestock farms, 265 cattle and buffaloes from two cattle/buffalo colonies and 200 consecutive cattle and 200 consecutive buffaloes from the slaughterhouse of Faisalabad, were included in this study. Tuberculin testing was performed on all the animals (cattle and buffaloes) above two years of age present at farms and colonies. Blood and faecal samples were gathered from tuberculin positive (reactor) animals. These samples were further processed by ELISA, ZN microscopy and PCR. Morbid tissue samples were collected from cattle and buffaloes slaughtered at slaughterhouse for histopathology and isolation of the organism. PCR test was used for further confirmation of Mycobacterium from farms, colonies and slaughterhouse also. The data collected from the study was analyzed by using frequency analysis and logistic analysis procedures. The study showed that the prevalence of Paratuberculosis at government livestock farms was 3.8% on the basis of tuberculin + ELISA test, while in case of two cattle/buffalo colonies it varied from 3.4-14.66%. Multivariate logistic regression analysis in both cattle and buffaloes at twelve livestock revealed that specie, milk production, total animals, total small ruminants and total buffaloes showed significant association with occurrence of Paratuberculosis while, the bivariate logistic regression analysis in cattle and buffaloes revealed that farm number, age and number of the total cattle showed significant association with occurrence of Paratuberculosis. Multivariate logistic regression analysis revealed that herd, age and lactation number showed significant association with the occurrence of Paratuberculosis, while the bivariate logistic regression analysis revealed that herd showed significant association with occurrence of Paratuberculosis. The slaughter house of Faisalabad was also included in the study. Out of total 200cattle and 200 buffaloes, suspected morbid samples of intestine and mesenteric lymph nodes from 25 cattle and 20 buffaloes were collected. These samples were further processed for histopathology and PCR. The main microscopic lesions observed in intestine were the diffuse inflammatory reaction with mononuclear cell infiltration and degenerative and necrotic changes in sub-mucosal glands along with the formation of immature granulomas. Relationship between Zn and PCR showed that 50% animals were found positive by both ZN and PCR. To compare the results of ELISA and PPD, an experiment was carried out on total 140 adult animals at Livestock Experimental Station University of Agriculture, Faisalabad. This revealed that ELISA showed more positive results than tuberculin testing. The study concluded that that tuberculin testing, ELISA, ZN staining and PCR are efficient diagnostic tools to diagnose the disease and use of combination of different tests improves the efficiency and confirmation of the disease.