Co‐occurrence and seasonal and environmental distributions of the sandflies Lutzomyia longipalpis and Nyssomyia whitmani in the city of Puerto Iguazú, northeastern Argentina

Abstract

The aim of this work was to study the distribution of Phlebotominae (Diptera: Psycodidade) abundance in time and space in an area in northeastern Argentina with vector transmission of visceral and tegumentary leishmaniasis. For this, 51 households were selected using a 'worst scenario' criterion where one light trap was set during two consecutive nights in peridomiciles in the transitions between the four seasons, and the environment was surveyed simultaneously. The relationships of phlebotomine assemblage structure and the most abundant species with seasonality and environmental variables were evaluated using a canonical correspondence analysis and generalized linear mixed models, respectively. A total of 5110 individuals were captured. Lutzomyia longipalpis (Lutz & Neiva, 1912) and Nyssomyia whitmani (Antunes & Coutinho, 1939) were the most abundant species captured in all samplings (98.3% of the total capture). The period of highest abundance of Lu. longipalpis was early autumn, and it was distributed in the most urbanized areas. Nyssomyia whitmani occupied mainly the less urbanized areas, showing peaks of abundance in early spring and summer. Other species were captured in low numbers and showed seasonal-spatial variations similar to those of Ny. whitmani. We confirmed Leishmania spp. vector persistence throughout the year in spatial patches of high abundance even during the less favorable season.

Multiscale environmental determinants of Leishmania vectors in the urban-rural context

“…longipalpis and periurban-rural Ny. whitmani in the area of the Argentina-Brazil-Paraguay border has already been described [29,42]. The rarefaction curves suggest that the peridomestic environment in rural landscapes seems stable and homogeneous enough to make the captures representative of their phlebotomine assemblages.…”

“…To describe the forestrelated populations properly a greater capture effort is required, but also a differentiated strategy of trapping due to the different strata in altitude related to the canopy, the lack of blood sources nearby the placement of traps that could affect the captures. Therefore, to avoid sporadic or unrepresented species in the modeling, only the well-represented species were analysed [15,17,46]. Thus, phlebotomine diversity both in rural and urban environments is related to the heterogeneity of the landscape.…”

“…The Iguazú waterfall area, located in Iguazú Department where the city of Puerto Iguazú is the most important urban area, reported CL outbreaks in 1998 (Puerto Esperanza), 2004 (Urugua-í), and 2005 (Puerto Iguazú) [12,13] and since then, regular cases are recorded every year. These cases are mainly related to deforestation, work forest-related risks, and peridomestic habitat close to the forest edge via the border effect [7,14,15]. Lutzomyia longipalpis was not found in the city of Puerto Iguazú before 2010 when was first found together with VL canine cases [12,16].…”

Presence of Lutzomyia longipalpis and Nyssomyia whitmani in Entre Rios, Argentina

“…The number of individuals obtained from both species is very low, but the climate conditions according to the records during the study were not optimal for the activity of phlebotomines 17 . Even though the scenario is adverse and there is eventual recent colonization, Lu.…”

Laboratory assessment of the anti-feeding effect for up to 12 months of a slow release deltamethrin collar (Scalibor®) against the sand fly Phlebotomus perniciosus in dogs

“…The extruded collar formulation used in this study provides extended deltamethrin release and is a key factor in the observed 12 month duration of anti-feeding efficacy. This extended duration of protection that could allow just once yearly treatment can be particularly relevant in geographies, for instance in areas of South America, where phlebotomine flies present an almost year-long risk of transmission of L. infantum [ 26 , 27 ]. Additionally, recent evaluation of long-acting ectoparasiticides has shown that increasing the duration of protection leads to increased owner compliance and therefore more months of protection during the year [ 28 ].…”