Phlebotominae: spatial-temporal distribution in Corrientes city, Argentina

BERROZPE, PABLO; SANTINI, MARÍA SOLEDAD; ARAUJO, ANALÍA VANESA; LAMATTINA, DANIELA; SALOMÓN, OSCAR DANIEL

Simposio; IX International Symposium on Phlebotomine Sandflies; 2016

Reports of cases of visceral leishmaniasis (VL) in canine reservoirs in Corrientes city prompted a search for sand fly vectors in2008. The presence of three species was confirmed: Lutzomyia longipalpis, vector of the causative agent of VL, Nyssomianeivai and the species complex Evandromyia cortelezzi-sallesi, vectors of the causative agents of Tegumentary Leishmaniasis(TL). Based on this information, this study was designed to study the spatio-temporal distribution of the Phlebotominae ofCorrientes, in order to establish seasonal (temporal) and environmental (spatial) profiles sand fly relative abundance asindicators of risk of exposure to sand fly bites. Relying on this information, it is hoped that distribution models can bedeveloped and validated in other endemic areas. Sociodemographic and environmental data (taken from satellite images) wereused to define three strata: rural immersed in a peri-urban matrix, peri-urban and urban. The sampling period was fromSeptember 2014 to August 2015, two samplings per season, and consisted of placing REDILA-BL minilight traps in sixperidomiciliary sites of each identified stratum for three consecutive, rainless nights. The sites were selected under ??worst casescenario?? criteria. Captured sand fly specimens were kept dry until diaphanized with lactophenol and identified using an optical microscope, following Galatti (2005). Spring: 662 Phlebotominae, 66% from rural stratum, 28% from peri-urban and 6%from urban stratum. Species: Rural stratum ? Lu. longipalpis (91%), Nyssomyia. neivai (7.5%), Migonemyia migonei (1.4%)and a single female Ev. cortelezzi-sallesi. Peri-urban stratum ? Lu. longipalpis (83.7%), Ny. neivai (15.7%) and a single femaleMg. migonei. Urban stratum ? Lu. longipalpis (100%). Summer: 2208 Phlebotominae, 77% from rural, 21% from peri-urbanand 2% from urban stratum. Species: Rural stratum ? Lu. longipalpis (30%), Ny. neivai (57%), Mg. migonei (10.5%) andEv. cortelezzi-sallesi (2%) and 3 female Micropigomyia quinquefer. Peri-urban stratum ? Lu. longipalpis (50%), Ny. neivai(40%), Mg. migonei (9%) and a single female Ev. cortelezzi-sallessi. Urban stratum ? Lu. longipalpis (100%). Autumn:723 Phlebotominae, 91% from rural stratum, 6% from peri-urban and 3% from urban stratum. Species: Rural stratum ?Lu. longipalpis (11%), Ny. neivai (80%), Mg. migonei (8.5%) and three female Ev. cortelezzi-sallesi. Peri-urban stratum ?Lu. longipalpis (68%), Ny. neivai (25%), Mg. migonei (7%). Urban stratum ? Lu. longipalpis (100%). Winter: 80 Phlebotominae, 56% from rural stratum, 15% from peirurban and 19% from urban stratum. Species: Rural stratum ? Lu. longipalpis(27%) and Ny. neivai (73%). Peri-urban stratum ? Lu. longipalpis (80%), Ny. neivai (20%). Urban stratum ? Lu. longipalpis(100%). The spatial distribution reveals that Lu. longipalpis is the only species present in all three environments. The remaining species were restricted to peri-urban and mostly to the rural stratum. The temporal distribution shows a bimodal abundancecurve with a peak in late spring and the other in late summer. This study identifies risk strata and moments of higherprobability of contact between humans and vectors for the study area. Differences in abundances between environmentalstrata could indicate that populations of phlebotomine species behave as metapopulations with recolonizations, in times ofgreater abundance, from the rural stratum to the other strata, and that Lu. longipalpis is the species with best colonizationsuccess.