Seroepidemiology and the molecular detection of animal brucellosis in Punjab, Pakistan

Abstract

Brucellosis is an infectious disease caused by bacteria of the genus Brucella (B.), affecting both animals and humans, causing severe economic loses and severe illness, respectively. The objective of the present study was to determine the seroprevalence and the risk factors associated with caprine, ovine, and bovine brucellosis in selected districts of Punjab, Pakistan. A total of 1083 blood samples were randomly collected from animals (goats = 440, sheep = 203, cows = 206, and buffaloes = 234). Questionnaires were used to collect data on risk factors associated with brucellosis on the sampling day. All samples were initially screened for anti-Brucella antibodies using the rose bengal plate test (RBPT). The seropositive serum samples were confirmed by a quantitative real-time polymerase chain reaction (PCR) assay for the detection of the Brucella genus-and Brucella species-specific DNA (B. abortus and B. melitensis). Univariant and binary logistic regression were used to identify important risk factors of brucellosis. Anti-Brucella antibodies and DNA were detected in 35 (3.23%) serum samples. Thirty-four (97.1%) DNA samples were confirmed as B. melitensis by qRT-PCR. Abortion history and natural mating were found to be potential risk factors. Brucella melitensis was identified as the causative agent of caprine, ovine, and bovine brucellosis in the selected districts of Punjab, Pakistan. Diseased animals may act as a source of infection for other animals. The elimination of positive seroreactors, development of control strategies for brucellosis, and education programs regarding the control of zoonotic disease are highly needed in developing countries like Pakistan.