Person-to-person transmission of Brucella melitensis.

Human brucellosis is primarily an occupational hazard in the USA; in the Middle East and Africa ingestion of contaminated dairy products is an important route of infection. Whether human beings can become infected via person-to-person spread is uncertain. During an investigation of a commonsource, laboratory-associated outbreak due to Brucella melitensis, biotype 3, the wife of a microbiologist with serologically proven brucellosis became infected. Her blood isolate was indistinguishable from the epidemic strain. In the absence of other risk factors, we suggest that sexual intercourse is a possible means of transmission.