Spatial distribution of synanthropic triatomines in Piaui State, Northeastern Brazil

Abstract

This study aimed to describe the spatial distribution and assess entomological indicators of synanthropic triatomines in Piaui State, Northeastern Brazil. We used surveillance data on the detection, identification and assessment of natural infection with trypanosomatids from triatomines in the State from 2014 to 2017. The State was divided into four macroregions. In relation to the dispersion rates of triatomines, they were much lower in the North, when compared to Southwest, Southeast and Central North macroregions. Infestation rates were higher in the Southwest and Southeast and intradomicile infestation rates varied during the study period, reaching high values in all regions. Insects belonging to the species Triatoma brasiliensis complex, Triatoma pseudomaculata, Triatoma sordida, and to the genus Panstrongylus spp. and Rhodnius spp. were collected during this period. T. brasiliensis was collected from all four regions of the State, but more frequently in those located in the Southeast. A similar pattern was observed for T. pseudomaculata. T. sordida was detected in the municipalities in the Southeast and Southwest regions, and less frequently in the Central North municipalities. Rhodnius spp. was detected in the Central North and North regions, and Panstrongylus spp. in the Central North and Southeast regions. The highest trypanosomatid-positivity rate of T. brasiliensis and Panstrongylus spp. was in the Southeast region. A significant proportion of the municipalities of Piaui State presents entomological parameters that indicate a risk of Chagas disease by vector transmission.

Figure 1. Map of Piaui State with the division of regions and type of vegetation.

Figure 2. Spatial variation of the entomological indicators in Piaui State in the years 2014 to 2017.

Figure 3. Distribution of triatomines in Piaui State by species, year and region, during the period from 2014 to 2017.

Figure 4. Geographical distribution of triatomine species in Piaui State from 2014 to 2017.

Figure 5. Geographic distribution of positive insects for trypanosomatids, distinguishing the different vector species of Chagas’ disease in Piaui State from 2014 to 2017.