SLAUGHTERHOUSE PREVALENCE AND DETERMINANTS OF BRUCELLOSIS IN CATTLE OF SYLHET METROPOLITAN CITY

Abstract

Brucellosis is one of the major bacterial zoonotic diseases worldwide with significant productive, public health and socio-economic impact. It is considered as one of the emerging infectious disease caused by Brucella spp. The epidemiology of brucellosis in slaughtered beef is unknown in Sylhet metropolitan city. Hence, a cross-sectional study was carried out with serum samples of 400 slaughtered cattle collected from 24 slaughterhouses selected from 8 different mahallas of Sylhet metropolitan city by multistage random sampling with their spatial location to estimate prevalence. It was followed by a case-control study for determining the risk factors associated with brucellosis in slaughtered cattle. The collected sera were tested with three tests namely Rose Bengal Brucella Antigen Test (RBT), Plate Agglutination Test for Brucella abortus (BPAT) and Serum Agglutination Test (SAT). A sample was considered to be positive if any one of these three tests showed positive reaction. From 400 serum samples 62 were shown positive reaction resulting 15.5% overall prevalence with 95% confidence interval (CI) 12.3% to 19.4%. Prevalence in female animals (15.76%; 95% CI, 11.60% to 21.10%) and in male animals (15.16%; 95% CI, 10.60% to 21.20%) showed significance differences. Relatively higher prevalence found in cross-breed slaughter cattle (33.33%; 95% CI, 17.2%-54.6%) than in local indigenous cattle (14.51%; 95% CI: 11.3%-18.4%). The highest prevalence was observed in cattle > 6 years of age (63.15%; 95% CI, 41.0%-80.9%) followed by cattle aged between 3-6 years (16.59%; 95% CI: 12.4%-21.8%) and cattle ≤ 3 years of age (7.14%; 95% CI: 3.9%-12.6%). It was found that cattle slaughtered at slaughterhouse practising poor hygiene condition had higher prevalence (19.54%; 95% CI: 14.8%-25.3%) than cattle from slaughterhouse with good hygiene practice (10.55; 95% CI: 6.9%-15.9%). From the multivariable logistic regression age and gender of the animal were determined as risk factors for having brucellosis. It was estimated that male animals were in higher risk than female animals having odds ratio (OR) of 2.86. It was observed that the risk of being infected by brucellosis is increased with the increasing of age. The cattle over 6 years of age were in higher risk (OR: 56.37) than the animal with age between 3-6 years and the animals in 3-6 years of age had relatively higher risk than animal ≤3 years old (OR:3.54). The prevalence was found higher than the other previous studies in different regions of Bangladesh indicating that slaughtered cattle could be a potential source of human infection in the study area. Public awareness about the bovine brucellosis in slaughtered cattle and national control measures are necessary to minimize the impact of brucellosis.