A longitudinal study of the incidence of leprosy in a hyperendemic area in Zaire, with special reference to PGL-antibody results. The Yalisombo Study Group.

Between 1984 and 1988, yearly surveys for leprosy were done among the 1500 people living in a previous leprosy segregation village in Zaire. In 1984 lepromin tests and phenolic glycolipid (PGL) antibody tests were done in a significant part of the population. The prevalence of the disease at that time was 16.1%, the proportion of multibacillary cases was 11.3% overall and 22% among active cases. Prior to 1984, 23% of paucibacillary cases and 56% of multibacillary cases had presented themselves spontaneously to the Leprosy Service. The exposure to the infection is uniform, but there is a suggestion of family clustering of cases. In spite of a rapidly bactericidal treatment of all known cases in 1984 and thereafter, the annual incidence of 0.34% did not decrease during the 4 years of the study. The PGL antibody test did not contribute to the diagnosis, classification or prognosis of the disease.