Brucella sp. was first isolated in marine mammals in 1994 from a bacterial isolate of an aborted bottlenose dolphin (Tursiops truncatus).1 It has been isolated from various marine pinniped species, as well as cetaceans, including the harp seal (Phoca groenlandica), hooded seal (Cystophora cristata), pacific harbor seal (Phoca vitulina richardsi), ringed seal (Phoca hispida), and Atlantic walruses (Odobenus rosmarus).1,2 Currently, serological and bacteriological tests have been the primary means of diagnosis. This research has lead to the development of a direct competitive enzyme-linked immunosorbant assay (cELISA) for the detection of marine Brucella sp. Using this competitive assay, 290 serum samples were tested. Of these samples, 247 were from harp seals, 36 hooded seals hooded seal, two bottlenose dolphins, and four unknown species. The dolphin samples were known to be positive and were provided to verify the functionality of the assay. Of the 290 samples, six were found to be positive for Brucella sp. antibodies. Of those six samples, three were from harp seals, one was from a hooded seal, and two were from known positive dolphin sera. Titers were determined for each sample, including rabbit serum controls, and ranged from 1:80 to 1:400.
The authors would like to thank Drs. J. Lawrence Dunn and Lisa Mazzaro at Mystic Aquarium for serum samples.
1. Forbes LB, Nielsen O, Measures L, DR Ewalt. 2000. Brucellosis in ringed seals and harp seals from Canada. Journal of Wildlife Diseases 36: 595-598.
2. Godfroid J. 2002. Brucellosis in wildlife. Revue scientifique et technique 21: 277-286.