Phlebotominae Bionomics in the Wet Chaco Bio-region. Chaco, Argentina

ENRIQUE ALEJANDRO SZELAG; JUAN RAMÓN ROSA; MATÍAS ARIEL PARRAS; OSCAR DANIEL SALOMÓN

Puerto Iguazú

Simposio; 8th International Symposium on Phlebotomine Sandflies; 2014

Instituto Nacional de Medicina Tropical - Ministerio de salud de la Nación

In Argentina, Tegumentary Leishmaniasis (TL) was first recorded in 1916. Actually is considered endemic in 9 provinces from north-east to north-west of the country. Urban Visceral Leishmaniasis (VL) produced the first autochthonous human case in Argentina in the city of Posadas in 2006. Currently, transmission is recorded in Misiones, Corrientes, Santiago del Estero, Formosa and Salta. In order to characterize the distribution in space and time of potential vectors of TL and VL; during the period October 2010 - September 2012 samplings were carried out in three areas of the Chaco province: Resistencia, Margarita Belén and Colonia Benítez. In each area an inhabited dwelling was selected, and CDC light traps were installed monthly during one single night from 7pm to 7am next day in domicile, Peri-domicile and forest. Data of Relative Humidity, High and Low Temperature, were recorded. The Phlebotominae captured were clarified and identified according to Galati (2003). A total of 1499 Phlebotominae was captured in this study. Eight species were recorded: Brumptomyia brumpti, Br. avellari, Evandromyia cortelezzii, Ev. sallesi, Migonemyia migonei, Sciopemyia sordelli, Nyssomyia neivai, Psathyromyia shannoni. Predominant species were Mg. migonei(41.03%) followed by Ny. neivai(38.96%) and complex cortelezzii(9.54%). The greater abundance of Phlebotominae was recorded in Forest(n=1003), followed by Peri-domicile(n=423) and domicile(n=73). Mg. migonei predominated in summer with an average temperature of 28.09°C and relative humidity of 61%, while in spring the most frequent species was Ny. neivai with averages of 22.5 ºC and 58% RH. The lower abundance of Phlebotominae was recorded between June and July. The increased frequency of these species in warm and dry months should be considered when proposing control measure. In conclusion, the presence of competent TL vectors as Ny. neivai and Mg. migonei (also a potential vector of VL) in the forest and in lower proportion in peridomestic environments, suggested for the region a risk of transmission of leishmaniases, mainly due to human activities related to the forest, but also by periodical colonization of the peridomestic areas with population of vectors from the forest. Further studies should determine for TL the role of Mg. migonei, the main vector in the Dry Chaco region, as an opportunistic vector in hot-spot transmission, and its interaction with Ny. neivai the main vector in the Wet Chaco region of Argentina.