Experimental assessment of the pathogenicity of Brucella strains from marine mammals for pregnant sheep

Strains of Brucella have been isolated from seals, dolphins and porpoises, which produced fulminating disease in guinea pigs. To assess if these strains had the ability to infect, cause clinical disease, or persist in a terrestrial host, sheep were inoculated during pregnancy, or before breeding, with porpoise, seal or dolphin marine-mammal isolates. Three groups of sheep were inoculated with representative Brucella isolates. Non-infected sheep (sentinels) were housed with these experimentally infected (transmission control) to assess the transmissibility of the marine strains between animals. There were no clinical signs of disease and the seroconversion rates were low. This indicates low pathogenicity of the three marine-mammal Brucella strains for sheep. In addition, a group of sheep were infected with the challenge strain of B. melitensis (H38) as a treatment standard. The likelihood of natural transmission of marine-mammal Brucella strains to sheep is discussed. Crown Copyright © 2003 Published by Elsevier B.V. All rights reserved.