"Phlebotominae (Diptera: Psychodidae) in an endemic site of the wet Chaco Region, Chaco Province, Argentina."

JUAN R. ROSA; ENRIQUE A. SZELAG; MARINA STEIN; OSCAR D. SALOMON; SANDRA V. SOBRADO; JORGE O. GORODNER

Lima, Perú.

Simposio; 6th Internacional Symposium on Phlebotomine Sandflies.; 2008

Universidad Peruana Cayetano Heredia. Instituto de Medicina Tropical Alexander von Humboldt.

Abstract During the last decades emergent outbreaks of American Cutaneus Leishmaniasis (ACL) were reported in the phytogeographical region of Wet Chaco, mainly associated with the gallery forests of the main rivers. With the aim to describe the sandfly fauna and their seasonal variation in a site with ACL cases but low endemicity, we carried out a study from November 2004 to October 2006 in Resistencia city (27º30´S, 59ºW). Regular collections were performed twice a month in two sites (A-B) in domestic (houses), and peridomestic (hen house and pigsty) habitats, and the forest, with CDC light traps (19:00 to 7:00h.). A total of 1459 sandflies were captured with a sex ratio M/F: 1,98/1. Lutzomyia neivai (83%), L. migonei (14%), L. cortelezzii (2%), L. shannoni (0,2%) and Brumptomyia brumpti (0,8%). Lutzomyia neivai y L. migonei predominated in the peridomestic habitat and the forest in both sites. L. neivai was only captured inside the house in site B, with two females. Phlebotomine were present all the year round, except March, June and July 2005, and September 2006. The seasonal distribution (year 100%)-average temperature(ºC)-rainfall(mm) was: Winter 49.82%-15.7ºC-8.3mm due to an exceptional temperate dry (mean temperature 27ºC), Spring 21.52%-22.8ºC-10mm, Summer 15%-27ºC-14.2mm, Autumn 13.63%-19.9ºC-22.2mm. Mainly due to L. neivai prevalent species the captures showed a trimodal pattern that peaks in April and November 2005, and July 2006. L. neivai and L. migonei were dissected in search for natural infections of Leishmania, none was found, PCR is also performed (ongoing result). Based on their abundance, distribution in the ecotone of the forest and peridomestic habitats, and literature about epidemic ´hos spots´ in the Wet Chaco, we conclude that L. neivai and L. migonei could be also the probable vectors in the region during inter-epidemis periods.