Epidemiological patterns of cutaneous leishmaniasis in Panama. III. Endemic persistence of the disease
Herrer, A.; Christensen, H.A.
American Journal of Tropical Medicine and Hygiene 25(1): 54-58
1976
ISSN/ISBN: 0002-9637 PMID: 816214 Document Number: 97871
Endemic persistence of cutaneous leishmaniasis is described in El Aguacate, a community established in the forest of central Panama about 75 years ago. Physiographical peculiarities partially isolate El Aguacate from other villages in the region. Some of the original forest environment has been preserved, and man-biting species of Phlebotomines were abundant as was the two-toed sloth (Choloepus hoffmanni), the principal reservoir host of Leishmania braziliensis in Panama. The inhabitants, as well as their dogs, were examined for natural leishmaniasis in 1969 and 1973. Mammals and Phlebotomines were collected from 1968 to 1973 in a search for reservoir hosts and potential vectors of the disease. Similar studies were undertaken in two nearby villages during 1968 and 1969. Lutzomyia gomezi (Nitzu.) was the most abundant Phlebotomine, with L. trapidoi (Fairchild & Hertig) the next most common. These two species and L. ylephiletrix (Fairchild & Hertig) are the suspected vectors of leishmaniae in El Aguacate, and these three and L. sanguinaria (Fairchild & Hertig) probably maintain the disease among two-toed sloths in forests surrounding the other two villages. Leishmania braziliensis has clearly persisted for many years in El Aguacate, and infection is acquired during childhood. Dogs also were found naturally infected, and the two-toed sloth showed yearly infection rates up to 47.8%. Parasites were also demonstrated in a night monkey (Aotus trivirgatus). Human cutaneous leishmaniasis was observed in El Aguacate, Panama, at a low infection rate in 1969 and 1973, with active cases restricted to young children. The continuous occurrence of human infections in this locality after about 75 years of habitation is a result of several factors, mainly preservation of part of the original forest environment, abundance of man-biting species of phlebotomine sandflies, presence of the 2-toed sloth (Choloepus hoffmanni) the principal reservoir of Leishmania braziliensis in Panama, and the rather isolated situation in which the El Aguacate community existed until 1973. Dogs were found to be naturally infected and the 2-toed sloth showed yearly infection rates of 19.0 to 47.8% from 1968 to 1973. One of 5 Aotus trivirgatus was also infected.