Eco-epidemiology studies on vectors of visceral leishmaniasis in Argentina.

SALOMON OD; SANTINI MS; ACARDI SA; FERNÁNDEZ MS; ROSA JR; SZELAG EA; PARRAS MA; QUINTANA MG; LIOTTA DJ; GOULD I

Kusadasi

Simposio; 7th International Symposium on Phlebotomine Sand flies; 2011

These studies are based on captures of phlebotomine performed in 12 provinces of Argentina and 2 departments of Uruguay. Lutzomyia longipalpis related to urban VL transmission was found for the first time in Argentina, in Clorinda (province of Formosa) on the border with Paraguay in 12/2004. However, the first human autochtonous case, with concurrent canine VL and Lu. longipalpis, was recorded during 5/2006 in Posadas (province of Misiones). Currently there are 84 human cumulated cases of VL with a letality rate of 9.5%. Micro-scale: The distribution of Lu. longipalpis by hour, the human-dog attractiveness, and the impact of current anti-vectorial insecticide measures were evaluated in Posadas focus. The parasite genotypification both in humans, dogs and vectors were performed by PCR-RFLP and sequencing-based confirmation assays, and the sex pheromone (col. JGC Hamilton) and period gene (col AA Peixoto) were characterized from phlebotomine of the same focus. Focus-scale: Lu. longipalpis urban heterogeneity of abundance was compared between 2007 and 2009 captures (sampled sites n > 300/survey)., and its association with environmental variables in the urban focus of VL in Posadas, were studied. The 2009-2010 insect captures was designed together with a sampling of canine infection, and interviews about perception and practices by anthropologists, both in areas of high abundance and low abundance of vectors. The clustered distribution of Lu. longipalpis in Posadas, Clorinda, and Santo Tomé (province of Corrientes) supported a dynamic metapopulation structure. Macro-scale: Due to the reports of canine VL, a search of the vector in the Province of Corrientes, contiguous to Misiones, was performed during 12/2008, and found Lu. longipalpis in 7 localities, otherwise in La Banda (province of Santiago del Estero, xerophytic Chaco) 4 human VL cases and 8 dogs with VL were associated with the presence of Lu. migonei. During the summer of 2009-2010 the dispersion of Lu. longipalpis was monitored with 534 trap/night in 53 localitues of Argentina and Uruguay (col Y Basmajdian), and Lu. longipalpis was found in almost all Corrientes, and reached Puerto Iguazu (Misiones) Chajarí (Entre Ríos), Resistencia (Chaco), places without Lu. longipalpis in previous captures, as Salto and Bella Union (Republic of Uruguay). The 2010-2011 monitoring is currently under analysis. In order to develop a map of vector potential distribution the data from the surveys and the Maximum Entropy's Modeling System method was used.