Epidemiology and Economic Impact Assessment of Caprine Brucellosis in Penang State, Malaysia: A Retrospective Analysis

Brucella melitensis is a zoonotic pathogen affecting a wide range of hosts with economic significance in the animal industry worldwide. The disease is characterized by abortion, still birth, reduced milk production, weak foetus and infertility mainly in small ruminant populations. There is a wide distribution of the disease among domesticated species and the trends of the disease in goats have not yet been described in Penang state, Malaysia. In this study we describe the distribution, pattern and trend of B. melitensis in Penang state based on serological data obtained from nationwide B. melitensis serosurveillance activities in goat populations. A total of 13,724 goats were sampled within the period of study (2012-2014), of which 3.4% (95% CI; 3.35-3.45) goats tested positive for B. melitensis infection. The district of Seberang Perai Utara had the highest animal seroprevalence of 95.5% (95% CI; 94.2-96.8). The seroprevalence varied over type of the breeds and the period of study and generally increased in 2014. Seropositive animals clustered around Boer and Katjang breeds with the prevalence of 54% (95% CI; 51.8-56.2) and 38% (95% CI; 35.8-40.2), respectively. The months of March, August and September, illustrated the highest seroprevalences of 44 (95% CI; 41.54-46.46), 13% (95% CI; 10.8-15.2) and 14% (95% CI; 11.3-16.7), respectively. A noticeable variation was observed in annual-level economic loses, but the seroprevalence remained significantly high in 2014 (>80%). Considering the lack of information on the epidemiology of caprine brucellosis in peninsular Malaysia, this report could contribute to the on-going area-wise national brucellosis eradication program.