Lutzomyia whitmani and Lu. migonei abundance changes associated with meteorological conditions in a Tegumentary Leishmaniasis endemic area in northeastern Argentina

FERNÁNDEZ MS; LESTANI EA; CAVIA R ; SALOMÓN OD

Kasadasi

Simposio; 7th International Symposium on Phlebotomine Sandflies; 2011

Lutzomyia whitmani and Lu. migonei are the most abundant phlebotomine in a recent deforested area in the northeastern of Argentinean, related to an American Tegumentary Leishmaniasis focus . Abundance changes of this phlebotomine were studied in three farms using CDC light minitramps from June 2006 to November 2007. Every fortnight, two minitramps were placed in each farm from 17:00h to 9:00h, one in a window of the house and one in the pigsties. Farms selected were close to a native rainforest border. Simple and partial Spearman correlation analysis was performed to analyze the association between the average abundance changes of Lu. whitmani and Lu. migonei with the meteorological variables. Also, we studied this association applying a delay to the average abundance of 15 days and up to 156 days. The minimum daily temperature increased the abundance of Lu. whitmani and Lu. migonei with a delay up to 30 days in both environments: the pigsties and the houses (p<0.05). A similar pattern was observed with the average and maximum daily temperature. When daily accumulated precipitations increased, Lu. whitmani abundance also increased with a 30-day delay in both environments. However, when the effect of the temperature was removed by partial correlation analysis, the association with precipitation became not significant. Lu. migonei abundance was marginally associated with precipitations (30-day delay, p<0.10) and only in pigsties. The increasing abundance of this phlebotomine following the increasing environmental temperatures (especially minimum temperature) may be related to the increase in metabolism in all the stages of the biological cycle, even the flying-food searching activity at the moment of the capture. The association with precipitations may be related to environmental relative humidity and soil humidity, which may affect larval survival. However, according to our results, temperature explained the observed changes in abundance better than precipitations, probably because precipitations are relatively abundant along the year in the study area. This hypothesis, as well as the relationships with this factor measured at a micro-scale level, should be further tested.