Development of Lutzomyia evansi immature stages in peridomiciliary environment in a leishmaniasis urban focus in the Colombian Caribbean

• Published in: Acta tropica Vol. 208; p. 105523
• Main Authors: Estrada, Luis Gregorio, Ortega, Edgar, Vivero, Rafael José, Bejarano, Eduar Elías, Cadena, Horacio
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-08-2020
• Subjects: Cordia alba; Lutzomyia evansi; Natural breeding sites; Peri-urban area; Soil physicochemical analysis; Natural breeding sites; Cordia alba; Lutzomyia evansi; Soil physicochemical analysis; Peri-urban area
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2020.105523

•Lutzomyia evansi shows an ecological plasticity to modified peri-urban environments.•Cordia alba was one of the plant species where a high number of immature Lu. evansi were found, and it was the most abundant tree species in the area.•The immature tend to develop in fertile loam soils with high organic matter.•The abundance of immatures increases with the high rainfall or the emergence of immatures begins with the high rainfall.
In the Caribbean region of Colombia, Lutzomyia evansi is recognized as the vector for Leishmania infantum and Leishmania braziliensis. Identifying breeding sites and surveying abundance of immature phlebotomine sand flies in urban foci of leishmaniasis are useful tool to design new vector control strategies. The objective of this study was to describe the natural breeding sites of Lu. evansi in peridomiciliary vegetation in a peri-urban area of the Colombian Caribbean region. Between 2013 and 2015, 466 microhabitats were sampled, collecting 621 kg of soil samples. The explored microhabitats were bases and tree holes, fallen trees, animal caves, leaf litter, domestic animal shelters, and the inside of dwellings. The immature phlebotomines were recovered by direct search under the stereoscope and incubation of soil samples. In total, 103 microhabitats, associated with 17 arboreal species, were identified as natural breeding sites. Of 422 immature sandflies detected, 98.6% were found in soils at the base of the trees. Eight species of the genus Lutzomyia were identified, of which Lu. evansi (52.6%) was the most abundant, followed by Lu. rangeliana, Lu. cayennensis cayennensis, Lu. atroclavata, Lu. micropyga, Lu. trinidadensis, Lu. dubitans and Lu. gomezi. The arboreal species Cordia alba was the most used by phlebotomines for the development of their immature stages. From 63 natural breeding sites identified 268 immatures were recovered including 176 Lu. evansi. The accumulated precipitation showed correlation (R2 = 0.643, p = 0.013) with the abundance of developmental stages, which increased in September and October. The natural breeding sites of Lu. evansi exhibited a local pattern of occurrence dependent on rainfall. The physicochemical analysis of the soil samples showed that the natural sites for C. alba were categorized as fertile loam soils. This is the first systematic study that estimates the temporal variation of immature sand flies in peridomiciliary vegetation in a peri-urban focus of leishmaniasis in Colombia.
Immature of Lutzomyia evansi were recovered in soil samples collected in tree bases. It was possible to characterize and identify several plant species that allow the development of immature. Cordia alba was where the largest number of natural breeding sites was found. These soils were characterized by being fertile loams compared to the soils found in other trees. [Display omitted]