Disseminated American cutaneous leishmaniasis.

BACKGROUND: While studying cutaneous leishmaniasis in the central part of western Venezuela, we found four cases of disseminated American cutaneous leishmaniasis, three from the Lara State and one from Portuguesa State. METHODS: A clinical history was taken for each of these patients, followed by microscopic examination of the Giemsastained smears from their cutaneous lesions and by a Montenegro skin test. Serum from a skin lesion were grown in Novy-MacNeal-Nicolle medium (NNN). Hamsters were inoculated with suspension of tissues taken from the patient's lesions. Biopsies were taken for histopathologic examination. Isolates from cultures on NNN medium and from hamsters were subcultured in Schneider's medium for parasite identification, using molecular techniques. Treatment with injections of N-methyl glucamine antimonate, 25 mg/kg/day was prescribed for each patient for 20 consecutive days and, after a week of rest, a second course of injections was administered. RESULTS: Patients had disseminated papular, ulcerous, nodular, and ulceronodular lesions on the skin. Smears of the skin lesions from all of the patients showed abundant amastigotes within histiocytes or free in the tissues. The skin test was negative in two patients. On histopathologic examination of skin lesions, mainly numerous vacuolated histiocytes filled with amastigotes were observed. Isolates from all the patients were identified as Leishmania venezuelensis. One of the patients healed after treatment with N-methyl glucamine antimonate. The others were resistant to this therapy. CONCLUSIONS: Diffuse cutaneous leishmaniasis can be caused also by Leishmania venezuelensis. Patients with nodular lesions who presented a negative Montenegro skin test were more resistant to treatment with specific pentavalent antimonials.

Antigenic analysis of Leishmania isolates from Tachira state, Venezuela.

Studies of cutaneous leishmaniasis in 3 endemic foci in Tachira state, western Venezuela have revealed sympatric populations of parasites causing both cutaneous and mucocutaneous disease. Immunological techniques and measurement of protease/acid phosphatase activities have been used to detect species-specific parasite antigens from 3 isolates from Tachira. Identified antigens of particular interest had molecular masses of 100, 82, 66, 50 and 27 kDa, but there was a high degree of heterogeneity between the antigens of the Tachira isolates and other Venezuelan strains of Leishmania braziliensis and L. mexicana. This heterogeneity has implications concerning the selection of antigens for use in serodiagnosis of leishmaniasis.

Cutaneous leishmaniasis in western Venezuela caused by infection with Leishmania venezuelensis and L. braziliensis variants.

Between 1975 and 1987, epidemiological studies were carried out in several rural and urban communities in the central part of western Venezuela, especially in the state of Lara. 115 positive cultures were obtained from human cases and identified by their reactivity patterns to a cross-panel of specific monoclonal antibodies using a radioimmune binding assay; 53 were Leishmania venezuelensis and 62 were L. braziliensis. Most of these stocks were also characterized by isoenzyme electrophoresis, which confirmed the identification of the L. venezuelensis isolates. The enzyme electrophoretic profiles of the L. braziliensis isolates, however, revealed two populations with distinct electromorphs, one related to the World Health Organization L. braziliensis reference strain while the other population appeared to be a hybrid between L. braziliensis and L. guyanensis. L. braziliensis variants showed the widest geographical distribution, and were found in 7 states: Districto Federal (Caracas); Lara (Barquisimeto, Crespo, Iribarren, Jimenez, Morán, Palavecino, Torres, Urdaneta); Nueva Esparta (Margarita); Portuguesa (Las Cruces, Rio Amarillo); Trujillo (Cuicas); Yaracuy (Agua Fria, Cambural, Guaremal); and Zulia (Zipa-Yare). L. venezuelensis was found in the following endemic regions: Lara (Barquisimeto, Iribarren, Jimenez, Morán); Merida (Zéa); and Yaracuy (Campos Elias), showing that this parasite has a much wider geographical distribution than was initially recognized and that both these species can occur simultaneously within the same endemic region. Five isolates of L. braziliensis were made from infected donkeys (Equus asinus) in Urdaneta, Lara State, suggesting a possible domestic reservoir of L. braziliensis.

Lutzomyia ovallesi (Diptera: Psychodidae) as a vector of cutaneous leishmaniasis in Venezuela.

In the search for vectors of cutaneous leishmaniasis in the Barro Negro forest, Duaca, Lara State, Venezuela, 4,864 wild-caught Lutzomyia females were dissected and examined for promastigotes. Natural infection was found in 25 (0.5%) Lu. ovallesi. By biological parameters and enzyme electrophoresis all isolates from Lu. ovallesi were indistinguishable from those obtained from humans and dogs in the same Region. The isoenzyme profile of these isolates appear to indicate that strains were a hybrid between Leishmania braziliensis and L. guyanensis.