Seropositivity and associated risk factors for bovine leptospirosis in dairy farms

Abstract

Leptospirosis is one of the most economically important diseases of the cattle and buffaloes population worldwide and is caused by serovars of pathogenic Leptospira. A pilot study was conducted in some of the dairy farms located in Telangana and Andhra Pradesh, endemic states of India, during 2017 to investigate the seropositivity of bovine leptospirosis in dairy animals and associated risk factors at the farm level. The semi-structured questionnaire was designed as per the literature and used to collect leptospirosis associated risk factors along with serum samples from eight non-vaccinated dairy herds. The collected serum samples (n=56) were examined for detection of leptospiral antibodies using the Microscopic Agglutination Test (MAT), the gold standard serological test. The Chi-square and odds ratio analyses were employed to identify the important risk factors for leptospirosis in dairy farms. The study revealed that the seroprevalence of bovine leptospirosis at an individual animal and farm level was 39.8% and 75%, respectively, associated with age (p=0.041) and the health status of the animal (p=0.0001) as the significant risk factors. The predominantly observed reacted serovars were Icterohemorrhagiae (31.8%), Hebdomadis (27.3%), Bangkinang (22.7%), Australis (18.2%), Djasiman, Hurstbridge, Panama, and Pyrogenes (13.6%). Further, studies are required to identify the appropriate farm level/animals level risk factors associated with bovine leptospirosis using large-scale sampling with a refined survey instrument tool.