A study on the epidemiology of bovine brucellosis in Punjab (India) using milk-ELISA

Abstract

Bovine brucellosis, caused by Brucella abortus, is a serious zoonotic disease manifested by reproductive disorders resulting in huge economic losses to dairy farmers. A random survey was conducted to study the epidemiology of brucellosis in Punjab (India) using sampling software Survey Toolbox. Two-stage sampling procedure was adopted; in the first step, villages were selected randomly from sampling frame of all the villages of Punjab followed by selection of owners, and animals in individual farms were identified using random sampling. In all, 32 villages were selected and then 345 animals (approximately 5%) were sampled from these villages. The milk samples collected were screened for brucella antibodies employing ELISA test. The overall apparent prevalence of brucellosis was found to be 18.26% (true prevalence - 17.68%). The prevalence in the central zone of the state was significantly higher, viz. 23.2% (chi square = 11.34, p < 0.01) compared to 14.2% in the sub-mountainous zone and 5.8% in the arid irrigated zone. The disease prevalence was found to be non-significantly higher (chi square 1.029, p = 0.310) in cattle (20.67%) compared to buffaloes (16.41%) and increased with age (chi square = 8.572, p < 0.05) in both species. There was significant association between disease and abortion (chi square = 22.322, p < 0.01) and maximum abortion cases due to brucellosis were found in > 6 month of gestation (95.7%). The disease was significantly associated with the retention of placenta (chi square = 8.477, p < 0.01), however there was no significant relationship of the disease with repeat breeding (chi square = 0.044, p = 0.834). The results of the study suggested that the accurate epidemiological scenario of the disease may be obtained by employing multistage sampling procedures using milk-based ELISA.