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.

Everton Falcão De Oliveira,Elisa Teruya Oshiro,Alessandra Gutierrez De Oliveira,Antônio Conceição Paranhos Filho,Eunice Aparecida Bianchi Galati,Aline Etelvina Casaril,Michelle De Saboya Ravanelli,Roberto Macedo Gamarra,Márcio José De Medeiros,Wagner Souza Fernandes,Marcelo Gustavo Lorenzo

doi:10.1371/journal.pone.0165155

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.

Highlights

The monthly distribution and abundance of sand flies is influenced by both biotic and abiotic factors
Temperature, humidity, and rainfall exert a direct influence on sand fly populations, with effects being dependent on the region, weather, and species analyzed [1,2,3,4]
Use of data obtained from satellite images, such as the normalized difference vegetation index (NDVI), has allowed the identification and monitoring of vegetation diversity, as well as the determination of geographical space and areas at risk of endemic diseases, such as visceral and cutaneous leishmaniasis, and how they affect vector populations [2,6,7,11,12]

Summary

Introduction

The monthly distribution and abundance of sand flies is influenced by both biotic and abiotic factors. Geospatial tools, geographic information systems (GIS), and geostatistics have facilitated studies on how health, the environment, and socioeconomic conditions are related with the temporal and spatial distributions of different diseases and vector populations [2,5,6,7,8]. Such studies have provided important information for health surveillance, providing data for monitoring and mapping risk factors, as well as providing better descriptions, understanding, and predictions of geographic distribution [5,7,8]. Use of data obtained from satellite images, such as the normalized difference vegetation index (NDVI), has allowed the identification and monitoring of vegetation diversity, as well as the determination of geographical space and areas at risk of endemic diseases, such as visceral and cutaneous leishmaniasis, and how they affect vector populations [2,6,7,11,12]

Objectives

Methods

Results

Conclusion