Ecological aspects of Phlebotomines (Diptera: Psychodidae) and the transmission of American cutaneous leishmaniasis agents in an Amazonian/ Guianan bordering area

Abstract

BackgroundAn entomological study was conducted in the municipality of Oiapoque (lower Oyapock River Basin) in the Brazilian side bordering French Guiana to gain information on the transmission pattern of American cutaneous leishmaniasis (ACL) in that region, presumed to reflect the classical Amazonian/Guianan enzootic scenario.MethodsThree ecologically isolated forested areas near urban environments were surveyed during the rainy and dry seasons of 2015 and 2016, using a multi-trapping approach comprising ground-level and canopy light traps, black and white colored cloth Shannon traps and manual aspiration on tree bases. Female phlebotomines were dissected to find infections and isolate flagellates from Leishmania spp. The strains were characterized by restriction fragment length polymorphism analysis and compared with those of local ACL cases and World Health Organization reference strains.ResultsNyssomyia umbratilis, Trichopygomyia trichopyga and Evandromyia infraspinosa were the most frequently found species. Findings on relative abundance, spatiotemporal vector/ACL congruence, natural infections and anthropophilic insights strengthened the Guianan classical transmission of Leishmania (Viannia) guyanensis by Ny. umbratilis and suggested further investigations for Ev. infraspinosa. Nyssomyia umbratilis showed an eclectic feeding habit, including bird blood. Ecological data and literature reports also included Psychodopygus squamiventris maripaensis and Bichromomyia flaviscutellata on the list of suspected vectors.ConclusionsThese findings contributed to understanding ACL ecoepidemiology in the Amazonian/Guianan scenario. Local studies are required to better comprehend the Leishmania spp. enzootic mosaic in specific ecotopes.

Leishmania DNA detection and species characterization within phlebotomines (Diptera: Psychodidae) from a peridomicile-forest gradient in an Amazonian/Guianan bordering area

“…As hypothesized, the phlebotomine species composition observed in this study were highly similar to that recently presented in our previous study [6]. Therefore, to avoid redundancy, the present discussion here is focused on the results of horizontal stratification and Leishmania DNA detection within the phlebotomine population.…”

“…Wild environment: Vila Vitória Road (03° 51’ 28.1” N, 51° 48’ 41.3” W), as described in our previous survey [6], a recently opened road that provides eastern access from Oiapoque to Vila Vitória. The forested area shows minimal evidence of human activity and is therefore considered to be well preserved.…”

“…In nature, ACL causative agents are maintained in a complex series of transmission cycles involving a variety of vectors and reservoirs [4]. The impact of natural, ecological, or man-made pressures can further complicate these relationships and lead to the formation of new transmission cycles [5,6].…”

“…We recently studied ACL ecology in this region, providing comprehensive insights based exclusively on the investigation of the wild environment [6]. However, thelack of data regarding ACL in anthropized environmentsmade usseek further information regarding horizontal stratification of the phlebotomine fauna associated with human dwellings.…”

Binational burden of American cutaneous leishmaniasis in Oiapoque, Amapá State, Brazil, bordering French Guiana

“…complexus, and Nyssomyia intermedia/Ny. neivai, have not been documented in the bordering region 10 . Even though Nyssomyia whitmani was reported, this fly is rarely present and there is strong evidence that this species is more likely to be associated with L. (V.) guyanensis transmission in the Amazon/Guianan ACL scenario 11 .…”