LEISHMANIOSIS IN ARGENTINA

SALOMÓN O.D.1, SOSA-ESTANI S.1, CANINI L.2, MONZANI S.3, GÓMEZ A.O.1, SEGURA E.L

Cartagena, Colombia

Congreso; XVth International Congress for Tropical Medicine and Malaria; 2000

The first mucocutaneous leishmaniasis (MCL) outbreak in Argentina in the last sixty years, took place in the middle of the 80's, in the Province of Salta, close to the NW border. The Salta incidence rate rose from 6.4 /100,000 in 1984 to 28,7/100,000 in 1985. The parasite was identified as Leishmania (Viannia) braziliensis. After this date several confirmed outbreaks were reported in 9 Provinces. In 1998 Argentina reported 1,243 MCL cases in two main foci  1) Salta, incidence rate 96.1/100,000, 2) Misiones (NO border), incidence rate 28.0/100,000. In our experience all cases were MCL, although two cases of Salta had Diffuse Cutaneous Leishmaniasis, whithout isolation data. Screening carried out in an epidemic foci (Salta 1998) showed a rate of reactive Leishmanin Skin Test (LST) of 18.8% (26/138) with 11.5% without clincial evidence (scar or lesion); while in other epidemic foci (Misiones1998) the rate of reactive LST was 6.1%(13/212) with 7.7% without clincial evidence. In Salta, in an endemic situation, we observed patients with LST reactive and 50% of them without clinical evidence. Other foci studies were performed in the provinces of Salta, Misiones, Chaco, Tucumán, Formosa, Santiago del Estero, and Catamarca. From 51.476 MCL foci related phlebotominae, Lutzomya intermedia relative abundance ranged from 93.8% to 100% in each focus. Lu. intermedia is the prevalent species in peridomestic environments associated with secondary forest, and modified gallery forest related with rivers. Lutyzomyia cortelezzii, Lu.migonei, Lu.shannoni, Lu.puntigeniculata (NW), Lu.whitmani, , Lu.migonei and  Lu.quinquefer., Lu.fischeri, Lu.pessoai, and Lu.misionensis (NE) are also ocassionally present in peridomestic habitats, and primary forest. Taking into account the entomological and epidemiological results, the outbreaks in Argentina may be driven by : 1) weather exceptional conditions, peridomestic transmission. 2) Deforestation, traditional  forest -related activity transmission. 3) Human settelments close to residual primary forest. Experimental control designs are being developed to each one of these scenarios.