Sand flies are insects of medical and veterinary importance, because some species are able to transmit several pathogens such as Bartonella spp., Phlebovirus spp., and protozoan parasites of the genus Leishmania (Ross). They are widely distributed in the Americas, with recordings ranging from Canada to Argentina. Approximately 500 Phlebotominae species are known in the Americas, of which it is considered that at least 56 are involved in the transmission of leishmaniasis (Maroli et al. 2012). Previous studies have shown that the phlebotomine fauna in Argentina consists of 32 species distributed in 14 provinces (Quintana et al. 2012; Sábio et al. 2015; Salomón et al. 2010). Of these species, Lutzomyia longipalpis (Lutz & Neiva), Nyssomyia neivai (Pinto), Ny. whitmani (Antunes & Countinho), Cortelezzii complex [Evandromyia cortelezzii (Brèthes) – Ev. sallesi (Galvão & Coutinho)], Micropygomyia quinquefer (Dyar) and Migonemyia migonei (França) have been found with DNA of Leishmania spp. (Moya et al. 2015). Five new records of species in the province of Chaco, obtained from different projects carried out between 2001 and 2015, four of which are also new records for Argentina, are described in this article. Their importance as potential vectors and the correct determination of the sympatric species is also discussed.

The aim of this work was to identify the natural breeding sites of sandflies in the province of Chaco, Argentina, for the first time. Preliminary studies were conducted in two different phytogeographic regions: dry Chaco (Parque Provincial Pampa del Indio), in January 2010, and humid Chaco (Resistencia, Margarita Belén and Colonia Benítez), from May-September 2010. A total of 127 samples were collected (Pampa del Indio: 15, Resistencia: 37, Margarita Belén: 36, Colonia Benítez: 39). A female of Migonemyia migonei was found in Pampa del Indio at the base of a bromeliad in the summer (January) and a pupal exuvium of a phlebotomine fly was found in Resistencia, in a place where dogs rested, in the winter (July). These findings highlighted these two sites as potential breeding sites. Because the existence of potential natural breeding sites for sandflies has been demonstrated in both forest and periurban areas, expanding the search efforts and characterising these sites will enable the development of specific study designs to gain insight into the spatial distribution of the risks posed by these vectors. The resulting information will serve as a basis for proposing and evaluating vector control measures

Lutzomyia longipalpis was recorded for the first time in Argentina in 2004, in the province of Formosa. In the following years, the vector spread to the south and west in the country and was recorded in the province of Chaco in 2010. From November 2010-May 2012, captures of Phlebotominae were made in the city of Resistencia and its surroundings, to monitor the spread and possible colonisation of Lu. longipalpis in the province of Chaco. In this monitoring, Lu. longipalpis was absent in urban sampling sites and its presence was restricted to Barrio de los Pescadores. This suggests that the incipient colonisation observed in 2010 was not followed by continuous installation of vector populations and expansion of their spatial distribution as in other urban centres of Argentina.