Serological and Molecular Screening of Camels for Brucellosis in Bikaner, Rajasthan, India

Brucellosis is an important zoonotic disease affecting domestic animals and humans worldwide. The present study was undertaken on camels in and around Bikaner city of Rajasthan state of India to assess the extent of prevalence of Brucellosis in camels in this region. Since Rose Bengal Plate test (RBPT) is a serological screening method for diagnosis of Brucellosis approved by the Office International des Epizooties (OIE), RBPT was employed for detecting antibodies against Brucella organisms in camels. Polymerase Chain Reaction is widely followed for molecular diagnosis of several infectious diseases. DNA from whole blood of camels was analyzed by PCR for detection of Brucella organisms in the blood of camels. Blood samples from 177 camels (108 males and 69 females) from Bikaner and nearby villages were analyzed for Brucellosis by RBPT. Fifteen camels [7 (46.66%) males and 8 (53.33%) females] were found positive. However, none of the DNA samples from whole blood (RBPT positive or negative) from 25 camels tested was Brucella positive by PCR. The serological results indicate that Brucellosis is prevalent in camels and is of public health significance in Bikaner and nearby villages in Rajasthan state of India. However, detection of DNA of Brucella organisms in blood by PCR may not be advised for regular screening for Brucellosis since there is intermittent bacteremia in Brucellosis and Brucella DNA may not be detectable in blood continuously throughout the course of the disease. This reminds us that the OIE has approved RBPT, but not PCR for screening of Brucellosis.