Spatial and temporal variation of Lutzomyia longipalpis in the City of Posadas, Misiones, Northeast Argentina.

FERNÁNDEZ MS; SANTINI MS; TARTAGLINO L; CAVIA R; SALOMÓN OD

Kasadasi

Simposio; 7th International Symposium on Phlebotomine Sandflies; 2011

Ege University Medical Faculty, Department of Parasitology

Visceral leishmaniasis has been described as a rural disease, with recent trends to generate urban outbreaks, being its principal vector in the region Lutzomyia longipalpis. The aim of this study was to analyze changes in spatial distribution of the abundance of Lu. longipalpis in Posadas, between 2007-2009. Adult phlebotomine were captured in peridomestic areas (400m each), during summer (n2007= 282; n2009= 310). We analyzed the spatial autocorrelation of the abundance of Lu. longipalpis (estimated as the number of individuals per trap/night), using the semivariogram function, estimating its parameters. We interpolated the abundance of the vector in both years using common Krigging and compared the observed spatial distributions. Lutzomyia longipalpis was found distributed throughout the study area in 41.5% (2007) and 31.0% (2009) of the homes, with an average of 8.3±40.6 (2007) and 22.3±93.2 (2009) phlebotomine per trap/night, showing a spatial autocorrelation of 590m and 688m respectively. In most of the city, abundance was lower than 30 phlebotomine per trap/night, there were plenty of sites with 30 to 60 phlebotomine and a pattern of "islands" with more than 60 phlebotomine. This pattern was not modified between years. However, these "islands" increased in size and number from 2007 to 2009, and only four of them maintained their location. The high variability observed in the abundance of Lu. longipalpis could be related to the spatial heterogeneity provided by the urban environment, which creates breeding sites and favorable survival, sites that move in time and space, according to microclimatic and microenvironmental conditions associated with peridomestic management practices.