Dr. K. Vrinda MenonSRIJI A. P.2024-05-162024-05-162022-10-19https://krishikosh.egranth.ac.in/handle/1/5810209109Leptospirosis is a neglected bacterial zoonotic disease with worldwide distribution posing significant threat to humans and animals. The present study was conducted to identify the risk factors associated with bovine leptospirosis in Pananchery panchayat and Irinjalakuda municipality in Thrissur district, Kerala. Blood and urine (102 each) samples from dairy cattle and water (50) samples were collected from both the study areas in pre and post-monsoon seasons. A survey was conducted at the time of sample collection in order to identify risk factors. Blood, urine and water samples were examined by Dark Field Microscopy (DFM) and were found to be negative. Microscopic Agglutination Test (MAT) of serum samples revealed seroprevalence of 25 per cent in pre-monsoon and 36.54 per cent in post-monsoon season from samples collected from Pananchery. In Irinjalakuda, 22 per cent and 28 per cent seroprevalence was observed in pre and post-monsoon seasons, respectively. The predominant serovars detected in both seasons were Hardjo (30 per cent in pre-monsoon and 28.95 per cent postmonsoon) and Grippotyphosa (16.67 per cent in pre-monsoon and 23.68 per cent in post-monsoon). Urine and water samples were subjected to PCR targeting 16S rRNA, lipl 21, lipl 32 and lipl 41 genes. On molecular analysis of urine by PCR, 15.38 per cent samples from Pananchery and 10 per cent samples from Irinjalakuda were found positive for leptospires in pre-monsoon. In postmonsoon, 23.08 per cent urine samples from Pananchery and 18 per cent from Irinjalakuda were detected by PCR. Pathogenic leptospires were detected in 5.88 per cent and 8.82 per cent of the urine samples in pre and post-monsoon, respectively. Analysis of water samples by PCR revealed that two per cent samples in pre-monsoon, 10 per cent of samples in post-monsoon were found to be positive without any significant difference between two study areas and two seasons. On molecular analysis, only six per cent water samples in post-monsoon revealed pathogenic leptospires. Initially, the risk factors were analysed by subjecting the data to univariate analysis (Chi-Square) for identifying risk factors associated with infection in both pre and post-monsoon seasons. The factors which were identified as significantly associated with leptospirosis in univariate analysis were then subjected to multivariate analysis. Using multivariate logistic regression analysis, possibility of contamination of grazing land with animal urine (OR=3.605; p<0.01) was identified as risk factor in pre-monsoon. In post monsoon, semi intensive and extensive system of rearing of animals (OR=6.493; p<0.01) and animals that used water sources shared by human and cattle for drinking (OR=2.487; p<0.05) were significantly associated with the presence of leptospirosis. The research revealed that apparently healthy cattle and water sources may lead to endemicity of disease in the area. Identification of risk factors will help to adopt proper intervention strategies to minimise the disease occurrence in endemic areas.EnglishThesis