The incidence of brucellosis clinical and latent among various groups of the population

Abstract

1. The population as a whole is exposed to Brucella infection by the consumption of infected milk. This does not appear to be a very potent source of infection as relatively few clinical cases of brucellosis occur, nor are many latent infections discovered by the agglutination reaction.2. Those exposed to contact with infected animals or meat, as are farm workers, slaughterers and butchers, run a greater risk of contracting infection. The risk is not, however, markedly increased when the contact is limited to the handling of carcasses or meat, milking or ordinary animal husbandry.3. Members of the veterinary profession, who assist in calving and remove placentas from infected cows are exposed to the greatest risk of infection. They come in contact with the greatest natural concentration of Br. abortus through the most dangerous route, the skin. Clinical brucellosis is not common among them, but many contract latent infection. 58·3% of post-graduate and 10·8% of undergraduate veterinary students were found to have agglutinins for Br. abortus in their serum. This should be borne in mind when a diagnosis of undulant fever is considered in a member of the veterinary profession.