Spatial distribution of triatomines in domiciles of an urban area of the Brazilian Southeast Region.

João Victor Leite Dias,Herton Helder Rocha Pires,Liléia Diotaiuti,David Eladio Gorla,Helen Rodrigues Martins,Dimas Ramon Mota Queiroz

doi:10.1590/0074-02760150352

Abstract

Reports of triatomine infestation in urban areas have increased. We analysed the spatial distribution of infestation by triatomines in the urban area of Diamantina, in the state of Minas Gerais, Brazil. Triatomines were obtained by community-based entomological surveillance. Spatial patterns of infestation were analysed by Ripley’s K function and Kernel density estimator. Normalised difference vegetation index (NDVI) and land cover derived from satellite imagery were compared between infested and uninfested areas. A total of 140 adults of four species were captured (100 Triatoma vitticeps, 25Panstrongylus geniculatus, 8 Panstrongylus megistus, and 7 Triatoma arthurneivai specimens). In total, 87.9% were captured within domiciles. Infection by trypanosomes was observed in 19.6% of 107 examined insects. The spatial distributions ofT. vitticeps, P. geniculatus, T. arthurneivai, and trypanosome-positive triatomines were clustered, occurring mainly in peripheral areas. NDVI values were statistically higher in areas infested by T. vitticeps and P. geniculatus. Buildings infested by these species were located closer to open fields, whereas infestations of P. megistus andT. arthurneivai were closer to bare soil. Human occupation and modification of natural areas may be involved in triatomine invasion, exposing the population to these vectors.

Highlights

Chagas disease represents a major public health issue in Latin American countries
This allochthonous species was found in domiciles throughout most the endemic area, other species of triatomine bugs were of primary importance in large areas of Brazil, especially Triatoma brasiliensis Neiva 1911 and Panstrongylus megistus (Burmeister 1835) (Dias 2007)
Fig. 1: number of triatomines by species captured in urban area of Diamantina, state of Minas Gerais, Brazil, September 2011-August 2014, according to month

Summary

Introduction

Human infection occurs mainly by vector-borne transmission, in which the protozoan Trypanosoma cruzi (Chagas 1909) is transmitted by infected triatomines (Hemiptera: Reduviidae) (Rassi Jr et al 2010). In Brazil, Chagas disease transmission has been associated with people living in rural areas and with poor housing conditions in which triatomines are able to colonise (Coura 2007). The species primarily involved in transmission of T. cruzi in Brazil during the XX century was the domestic insect Triatoma infestans (Klug 1834). This allochthonous species was found in domiciles throughout most the endemic area, other species of triatomine bugs were of primary importance in large areas of Brazil, especially Triatoma brasiliensis Neiva 1911 and Panstrongylus megistus (Burmeister 1835) (Dias 2007)

Objectives

Methods

Results

Conclusion