Spatio—Temporal distribution of a vector of cutaneous leishmaniasis: Pintomyia longiflocosa, in a population from the Colombian Andean Mountains

TL;DR

This study examines how the sand fly Pintomyia longiflocosa, a vector for cutaneous leishmaniasis, is distributed in different environments and how weather affects its population in Colombia.

Contribution

The study identifies outdoor areas and dry seasons as key factors in the density of Pintomyia longiflocosa, offering new insights for targeted vector control.

Findings

Pintomyia longiflocosa was the dominant sand fly species, making up 98.86% of the collected samples.

Outdoor areas had the highest sand fly density, with females contributing more to the population than males.

Precipitation showed a negative correlation with sand fly density, with higher rainfall leading to lower abundance.

Abstract

Leishmaniasis, a neglected disease and public health concern, is associated with various factors such as biological, social, economical conditions and climate, increasing the risk of human infection. Understanding the population dynamics of the vectors, like Pintomyia longiflocosa, and its relationship with ecological variables is crucial for developing effective strategies to control sand fly populations and combat cutaneous leishmaniasis in a tropical country like Colombia.

Adult sand flies were collected in three different sample locations: outdoor, indoor, and peri-domestic areas in three houses located in the rural settlement of Campoalegre (Huila) between February 2020 and February 2021, using the CDC light traps. The sand fly density was quantified and associated with the sample locations and the sampling months using Analysis of Variance and Pearson correlations.

In the period of the sample, 98.86% of sand fly collected was identified as Pi. longiflocosa. The density of this species was significantly different between males and females, the latter contributing more to density in all sample locations (P<0.0001). The outdoor was the sample location with the highest and most significative density in this study (70%, P = 0.04). The density of these sand flies is related to the seasonality of Campoalegre, revealing a density peak from February and June to October (P < 0.05). Finally, precipitation is the environmental variable prominently linked to the density pattern, showing a negative correlation with it. Months with the highest precipitations show the lowest values of Pi. longiflocosa abundance.

Our investigation reveals a inverse correlation between precipitation levels and the abundance of Pi. longiflocosa in Campoalegre (Huila), particularly in outdoor areas. This suggests that vector control strategies to periods of reduced precipitation in outdoor settings could offer an effective approach to minimizing cases of cutaneous leishmaniasis in the region.

Understanding the population dynamics of Pintomyia longiflocosa (named before like Lutzomyia longiflocosa), and its interaction with ecological variables is crucial for devising effective strategies to control sand fly populations and combat cutaneous leishmaniasis, a neglected tropical disease, and a significant public health challenge in tropical countries like Colombia. To investigate this, we collected adult sand flies from outdoor, indoor, and peri-domestic areas in Campoalegre, Huila, Colombia, The density of Pi. longiflocosa, comprising 98.86% of the collected sand flies, with females contributing more to the overall density. Outdoor areas exhibited the highest density, highlighting their importance in the transmission of the disease. Additionally, the density of this sand flies showed a seasonal pattern, peaking from February to June and October, aligning with the local climate conditions. Notably, precipitation emerged as a significant environmental variable, displaying a negative correlation with sand fly density. Months with higher rainfall had lower abundance of Pi. longiflocosa. Overall, our study provides valuable insights into the population dynamics of the sand fly vector and its correlation with ecological factors, paving the way for effective control strategies to combat cutaneous leishmaniasis in Colombia.

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