ABSTRACT
The incidence of clinical and infraclinical human brucellosis was estimated by survey undertaken in 1976 on a representative sample of the population of the Vaucluse (France) district. It is shown that, by combining research of late hypersensitivity and serologic tracking in 2084 individuals, the incidence of diagnosed clinical brucellosis, in the Vaucluse district is at least 3 to 5 times more important than the incidence evaluated by the official notifications, and that there are 10 times more infraclinical or non diagnosed brucellosis than diagnosed brucellosis. The results show the need of triple investigation by interview, serology and hypersensitivity test (complementarity of the three technics) so as to evaluate the true morbidity of this anthropozoonosis.