Monthly Distribution of Phlebotomine Sand Flies, and Biotic and Abiotic Factors Related to Their Abundance, in an Urban Area to Which Visceral Leishmaniasis Is Endemic in Corumbá, Brazil

Abstract

The monthly distribution and abundance of sand flies are influenced by both biotic and abiotic factors. The present study aimed to evaluate the seasonal distribution of sand flies and the relation between their abundance and environmental parameters, including vegetation and climate. This study was conducted over a 2-year period (April 2012 to March 2014). Monthly distribution was evaluated through the weekly deployment of CDC light traps in the peridomicile area of 5 residences in an urban area of the municipality of Corumbá in the State of Mato Grosso do Sul, Brazil. Meteorological data were obtained from the Mato Grosso do Sul Center for Weather, Climate, and Water Resources. The spectral indices were calculated based on spatial resolution images (GeoEye) and the percentage of vegetal coverage. Differences in the abundance of sand flies among the collection sites were assessed using the Kruskal-Wallis test, and the strength of correlations between environmental variables was determined by calculating Spearman’s correlation coefficients. Lutzomyia cruzi, Lu. forattinii, and Evandromyia corumbaensis were the most frequently found species. Although no significant association was found among these sand fly species and the tested environmental variables (vegetation and climate), high population peaks were found during the rainy season, whereas low peaks were observed in the dry season. The monthly distribution of sand flies was primarily determined by Lu. cruzi, which accounted for 93.94% of the specimens collected each month throughout the experimental period. The fact that sand flies were detected year-round indicates a continuous risk of infection to humans, demonstrating the need for targeted management and education programs.

Geo‐climatic factors in a newly emerging focus of zoonotic visceral leishmaniasis in rural areas of north‐eastern Iran

“…GIS has been extensively used for generating risk maps for the vector-borne diseases (Palaniyandi, Anand, Maniyosai, Mariappan, & Das, 2016;Rai & Nathawat, Nathawat, 2017). GIS and following statistical models have been used to clarify the main determinants of leishmaniasis occurrence in various epidemiological foci (Fakhar et al, 2017;Oliveira et al, 2016).…”

Ecological niche modelling and predicted geographic distribution of Lutzomyia cruzi, vector of Leishmania infantum in South America

“…cruzi abundance and climatic variables showed no significant statistical association [ 24 , 27 , 59 ]. However, it was observed that the species occurs throughout the year, with population peaks in the months with high temperature [ 21 , 24 , 27 , 59 ]. These previous studies considered both male and female specimens of L .…”

“…In Brazil, the geographical distribution of L . cruzi seems to be restricted and limited to Cerrado and Pantanal biomes [ 23 , 24 , 27 – 29 ]. There are also reports of the presence of L .…”

“…Even though L . cruzi has medical and epidemiological relevance, until now there are few published reports focused on the ecology and effects of environmental variables on the distribution and abundance of this sand fly [ 19 , 21 , 27 , 28 , 33 , 34 ]. A recent study applied ecological niche models to predict the distributions of L .…”

Reciprocal interactions between Leishmania and their microenvironments during infection in the sand fly gut and human macrophages

“…Using this method, engineered bacteria such would be introduced to field endemic sand fly breeding habitats or bait-traps, and thus incorporated into the larval microbiome where the bacteria would persist through adulthood [240,244,245]. Proper evaluation of the sand fly life cycle and seasonal variation in the population would be important to determine when application of the paratransgenic bacteria be administered to the environment [246][247][248][249]. Because the sand fly midgut microbiome is unusually diverse for an insect vector, there are many opportunities to generate a paratransgenic bacterial species that could provide anti-Leishmania properties in the adult female fly.…”