Lutzomyia longipalpis (Leishmania infantum vector) and Nyssomyia whitmani (Leishmania braziliensis vector) in the city of Puerto Iguazú, northeastern Argentina: seasonal abundance and relationship with domestic animals

FERNÁNDEZ, MARÍA SOLEDAD; SANTINI MARIA SOLEDAD; CAVIA REGINO; SALOMÓN OSCAR DANIEL

Puerto Iguazú

Simposio; VIII International Symposium on Phlebotomine Sandflies; 2014

In this study the city of Puerto Iguazú was sampled from spring 2011 to winter 2012 to evaluate seasonal abundance changes of sandflies. The city was divided in 51 areas of 400x400m where minilight traps were located at the beginning of every season during two consecutive nights in peridomiciles of households. Lutzomyia longipalpis and Nyssomyia whitmani represented the 97.5% of the captures (N=5409 sandflies). Two abundance indexes were analyzed for each species: the occurrence and the number of individuals captured by night in each household. The seasonality of occurrence and abundance by species was evaluated using Generalized Linear Mixed Models. We also evaluate the effect of the number of dogs and chickens on the occurrence of sandflies at each household. For both analyses, household were considered as a random effect. Both species showed differences by season in the number of households-occurrence and number of individuals captured, but with different patterns. The percentage of households with Lu. longipalpis was higher in fall (66.7 %) compared to spring (31.4%) and summer (27.5%), and lower in the winter (10.2%). The percentage of households with Ny. whitmani was minimum in fall (9.8%) and was maximum in summer (39.2%) and spring (31.4%), while winter has an intermediate value (22.5%). The occurrence of both species was positively associated with the number of dogs and chickens in the households. For Lu. longipalpis also a synergic effect was detected in the number of dogs and chickens, while for Ny. whitmani the effect of the number of chickens varied among seasons. The percentage of households infested with both species was maximum at the spring (21.5%) and summer (23.5%). The number of individuals captured of both species changed according to the seasons similarly to the occurrence. Lu. longipalpis abundance was higher in fall (27.8 Phlebotomine per trap-night [PTN]) compared to spring and summer (5.6 and 5.3 PTN) and the winter was the season with the lower value (0.6 PTN). Ny. whitmani numbers were minimum in fall and in winter (1.0 and 0.4 PTN) and were higher in summer and spring (12.0 and 6.8 PTN). These results shows that in the study area these sandflies have different patterns of abundance according to the seasonality and also the numbers of domestic animals in the households as chickens or dogs, and so the seasonal and space-environmental risk is different for cutaneous leishmaniasis and visceral leishmaniasis in the same city.