EFFECT OF ELIMINATING SEROPOSITIVE CANINES ON THE TRANSMISSION OF VISCERAL LEISHMANIASIS IN BRAZIL

In Brazil, where Leishmania chagasi causes endemic American visceral l eishmaniasis (AVL), the spread and maintenance of human disease are at tributed to canine reservoirs. However, despite measures directed towa rd the elimination of infected canines, the incidence of human disease continues to increase, To evaluate the role of infected canines in th e acquisition of AVL by humans, we undertook a controlled intervention study in three similar, but isolated, valleys of Pancas, Espirito San to, Brazil, In the two experimental (intervention) valleys, infected d ogs were eliminated whereas in the control valley, seropositive canine s remained untouched. During the 12-month study period, human seroposi tivity rates, as measured by dot enzyme-linked immunosorbent assay, in creased from 15% to 54% in the intervention valleys and from 14% to 54 % in the control valley, The elimination of infected canines in the in tervention valleys did not result in a statistically significant diffe rence between the incidences of human serological conversion in the in tervention and control valleys at either 6 (20% and 22%, respectively; P = .5961) or 12 months (26% and 27%, respectively; P = .9442), The r ole of humans as a significant reservoir for AVL is proposed as an exp lanation for the study results.