Abstract

The leishmaniasis is a complex disease system, caused by the protozoan parasite Leishmania and transmitted to humans by the vector Lutzomyia spp. Since it is listed as a neglected disease according to the World Health Organization, the aim of this study was to determine the current and future niche of cutaneous and visceral leishmaniasis in the Neotropical region. We built the ecological niche model (ENM) of cutaneous (N= 2 910 occurrences) and visceral (N= 851 occurrences) leishmaniasis using MaxEnt algorithm. Nine bioclimatic variables (BIO1, BIO4, BIO5, BIO6, BIO7, BIO12, BIO13, BIO14, BIO15 (downloaded from the Worldclim) and disease occurrences data were used for the construction of ENM for three periods (current, 2050 and 2070) and four climate change scenarios (RCP 2.6, 4.5, 6.0 y 8.5). We analyzed the number of pixels occupied, identity niche, modified niche (stable, loss, and gain) and seasonality. Our analyses indicated the expansion for cutaneous leishmaniasis (CL), a comparison for visceral leishmaniasis (VL). We rejected the null hypothesis of niche identity between CL and VL with Hellinger’s index = 0.91 (0.92-0.98) and Schoener’s Index = 0.67 (0.85-1.00) but with an overlap niche of 56.3 %. The differences between the two leishmaniasis types were detected in relation to RCP scenarios and niche shifts (area gained / loss). Seasonality was more important for CL. We provided a current picture of CL and VL distributions and the predicted distributional changes associated to different climate change scenarios for the Neotropical region. We can anticipate that increasing range is likely although it will depend locally on the future trends in weather seasonality.

Highlights

  • La leishmaniasis es una de las principales enfermedades tropicales desatendidas a nivel mundial

  • Esta enfermedad consiste en cuatro formas clínicas producidas por diferentes agentes etiológicos, todos ellos parásitos tripanosomatídeos pertenecientes al género Leishmania Ross (Kinetoplastida: Trypanosomatidae), y transmitidas por la picadura de flebotomineos hembras (Psychodidae: Phlebotominae) que afectan a las poblaciones de animales y humanos a lo largo de gran parte de las zonas tropicales y subtropicales

  • Lutzomyia vectors for cutaneous leishmaniasis in Southern Brazil: ecological niche models, predicted geographic distributions, and climate change effects

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Summary

MATERIALES Y MÉTODOS

Origen de datos: El área de estudio incluye toda la región Neotropical con una extensión de 23 676 710 km en 21 países latinoamericanos y una población estimada de 960 millones de habitantes (www.bankworld.org). Nicho ecológico: Para la construcción de los MNE, se usaron nueve variables bioclimáticas (BIO1, BIO4, BIO5, BIO6, BIO7, BIO12, BIO13, BIO14, BIO15) descargadas de Worldclim (www.worldclim.org/) con un tamaño de pixel de 2.5 minutos de longitud y latitud (aproximadamente 4.5 km). Utilizamos la prueba de “identity test” para evaluar la identidad del nicho ecológico de LC y LV en el periodo actual, mediante los siguientes parámetros: puntos de entrenamiento (75 %), máximo número de iteraciones (500), tipo de réplica (bootstrap) y threshold (minimum training presence) mediante el software ENMtools (Warren, Glor, & Turelli, 2010). Nicho actual: El nicho ecológico de LC, se distribuye desde México hasta Argentina y parte de Chile, a excepción de las regiones elevadas de la Cordillera de los Andes (Fig. 1A). Leishmaniasis visceral Bio 12 (34.7) Bio 7 (23.3) Bio 1 (20.3) Bio 6 (10.5) Bio (3.8) Bio 4 (2.4) Bio 5 (2.3) Bio (1.6) Bio 13 (1.1)

Leishmaniasis visceral
Findings
Temperatura anual
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