Triatomine Fauna and Recent Epidemiological Dynamics of Chagas Disease in an Endemic Area of Northeast Brazil

Abstract

Updated information of the dispersion dynamics of Chagas disease (CD) and a systemic analysis of these data will aid the early identification of areas that are vulnerable to transmission and enable efficient intervention. This work synthesized spatiotemporal information regarding triatomine fauna and analyzed this information in combination with the results from serological tests to elucidate the epidemiological panorama of CD in the state of Sergipe, Brazil. This is a retrospective analytical study that utilized information from the database of the National Chagas Disease Control Program. Between 2010 and 2016, 838 triatomines of eight species, namely, Panstrongylus geniculatus, which was first recorded in the state of Sergipe, Panstrongylus lutzi, P. megistus, Triatoma brasiliensis, T. pseudomaculata, T. tibiamaculata, T. melanocephala, and Rhodnius neglectus, were collected. Optical microscopy revealed that 13.2% of triatomines examined were infected by Trypanosoma cruzi-like flagellates. The distribution of triatomines exhibits an expanding south-central to northern dispersion, with a preference for semiarid and agreste areas and occasional observations in humid coastal areas due to anthropogenic actions reflected in the environment. Of the human cases analyzed from 2012 to 2016, 8.3% (191/2316) presented positive serology for Trypanosoma cruzi, and this proportion showed a gradual increase in the southern center of the state and new notifications in coastal regions. There is a need for intensification and continuity of the measures adopted by the Chagas Disease Control Program in Sergipe, identifying new priority areas for intervention and preferential ecotopes of the vectors, considering the occurrence of positive triatomines intradomicilliary and a source of new triatomines in the peridomiciles.

Infestation dynamics of Triatoma dimidiata in highly deforested tropical dry forest regions of Guatemala

“… 25 It has been demonstrated previously that areas with very degraded forests have little or no wild triatomine presence. 26 A drastic reduction of the T. cruzi infection in wild mammals, such as opossum, is also an indication of the absence of triatomines in very deforested regions. 27 This suggests that, in our study area, a tropical dry forest region with a history of strong deforestation driven by economic activities like monocultures and cattle pastures, the forest coverage does not currently influence the infestation and reinfestation patterns of T. dimidiata because the degradation and deforestation have reached a point where there are no surviving wild vector populations.…”

Spatial distribution of triatomine bugs in a Chagas disease endemic region in Brazil

“…Various species were captured during the study (i.e., P. lutzi, T. brasiliensis, T. pseudomaculata and P. megistus), with P. lutzi being the most frequent (30.36%). This species had been already detected in other Brazilian regions 12,17 , and is relevant for the persistence of CD in endemic areas 21 . From an epidemiological perspective, P. lutzi plays a crucial role in the dynamic of T. cruzi infection in Northeastern Brazil, since it feeds on a wide plethora of hosts (e.g., birds, rodents, marsupials, dogs, goats, and humans), many of which are commonly found within the study area 9 .…”

“…The dispersion of triatomines in different environments may be related to mating or a search for food 19 . In this study, the presence of nymphs intradomicile indicates the formation of colonies in these environments represented by the phenomenon of domiciliation, and consequently high risk for human infection 7,12 .…”

“…For instance, in the Southeast region, P. megistus has been retrieved in urban areas 10 , while in the South Brazil, Triatoma circummaculata and Triatoma rubrovaria 11 have been reported as the most commonly detected species. In the Northeastern region species such as Triatoma brasiliensis, Panstrongylus lutzi and Triatoma pseudomaculata are frequently reported 7,9,12 . It is important to note that several natural environments in this region (e.g., xerophilous trees and rocks) are inhabited by triatomines 13 .…”

Psammolestes tertius Lent & Jurberg, 1965 (Hemiptera, Reduviidae, Triatominae): first report in Sergipe State, Brazil

“…In the Sergipe state, northeastern Brazil, all the following species have already been reported: Panstrongylus lutzi Neiva and Pinto, 1926 14,[17][18][19][20][21] . Although Sergipe borders Bahia and Alagoas, which are states where P. tertius occurs, this is the first record of this species in that state.…”