Natural breeding sites of Phlebotominae (Diptera: Psychodidae) in a flood zone of Chaco, Argentina

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

Puerto Iguazú

Simposio; 8th International Symposium on Phlebotomine Sandflies; 2014

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

Phlebotomine preimaginal sampling was performed from August 2011 to April 2014 in Puerto Antequeras (27° 26´34"S, 58° 50´ 57" W) where adults of Lutzomyia longipalpis and Nissomyia neivai where already reported as the main vectors of visceral and cutaneous leishmaniasis respectively. Two homes apart 3km from each other were selected, with the criteria of ?worst scenario?. From August 2011 to March 2013 substrate samples 10cm diameter by 3 cm deep were taken monthly; and from April 2013 until April 2014 emergence traps were installed modified from Casanova, 2001. In each home three ecotopes were selected: domestic (external walls of the houses and the contiguous sandy soil with plant debris), peridomestic (cattle pens, hen houses and kennels) and extra-domestic (base and hollows of trees and fallen logs and exposed roots). In the latter ecotope three points (trees) were selected at 100m distant from each other, along a transect from the domicile . The collected soil samples were kept at 24±5ºC and 80±10% relative humidity and observed daily for 60 days in search of the emergence of imagos for identification to species level. After this period the renmaining of the samples were processed by flotation with supersaturated solution of NaCl and observed under stereomicroscope looking for larvae, pupae, adults dead and/or pupal exuvium. The emergence traps were controlled every 15 days to renew the sticky paper; each trap remained in the soil for 60 days and then were moved to another point considered as potencial breeding site of sandfly within the same ecotope and mictrohabitat. A total of 950 substrate samples were taken and a male of Ny. neivai was obtained during flotation of a sample taken from the forest 100 meters from the house, at the base of a fallen tree in January (summer). As a result of the emergence traps 5 specimens of Ny. neivai were obtained (2 males and 3 females) distributed in four out of the forty traps , one located in peridomestic ecotope (hen house) and three located at the base of a tree in the forest (2 traps located 100mts and the other 2 200mts from the house). Of the specimens obtained, 4 were in months before an extraordinary flood occurred between June and July 2013 and 1 was recovered nine months after that flood (in April 2014). A production of 3.60 phlebotominae/100m2/day was estimated. These preliminar results showed the fitness of.the floodplain area of the Parana River in the province of Chaco for natural breeding sites of Ny neivai, distributed both in a peridomestic hen house but more frequently in the forest, a trend consistent with extradomestic source populations for this species. These studies are continued broadening the environmental range to support the hypothesis and looking for the breeding sites of Lu. longipalpis.