The diagnosis of brucellosis in female camels (Camelus dromedarius) using the milk ring test and milk ELISA: A pilot study

A study was conducted to evaluate the milk ring test (MRT) and the ELISA for the detection of Brucella antibodies in camel milk. Seventy-one female camels were screened for Brucella antibodies with the Rose Bengal plate test (RBPT) and the serum agglutination test (SAT). The five camels that tested positive in RBPT and SAT were retested with a serum antibody ELISA. Three of these camels were lactating. Milk samples from these camels along with 18 milk samples from seronegative camels were tested using the following methods: MRT, modified MRT, milk and whey-ELISA. Three milk samples from seropositive camels tested negative in the conventional MRT but the milk always became extremely white after incubation. When Brucella negative cow milk was added to the milk from seropositive camels, a distinct blue ring appeared at the top of the milk column in the MRT. Milk from seronegative animals remained blue after incubation, indicating a negative result. Milk and whey from seropositive camels tested positive in the ELISA whereas milk from seronegative camels tested negative. The results of this pilot study show that the modified MRT or the ELISA might be useful to screen camel milk for Brucella antibodies.