Evaluation of natural foci of Panstrongylus megistus in a forest fragment in Porto Alegre, State of Rio Grande do Sul, Brazil

Abstract

Introduction:Panstrongylus megistus is commonly found in wild environments of the State of Rio Grande do Sul, Brazil. The aim of this study was to characterize the network of refuges used by triatomine in a forest fragment of Porto Alegre and to identify Trypanosoma cruzi infection, associated hosts and the epidemiological importance of both hosts and triatomines. Methods: Techniques including the spool-and-line method and active searching (transects) were used to identify natural foci. Results: The food source for each triatomine was determined using the precipitin test, and the infection of marsupials was determined by xenodiagnosis. A total of 33 adults (domestic environment) and 27 nymphs (wild environment) of P. megistus were found in addition to 43 Didelphis albiventris specimens. The infection rates of triatomine adults, triatomine nymphs and opossums with T. cruzi I were 64%, 73% and 69%, respectively. Birds, rodents and opossums were the main resources used by triatomine. Conclusions: This work presents the fi rst characterization of a natural focus of P. megistus in Rio Grande do Sul. The natural characteristics of this focus and its implication in the transmission of T. cruzi are discussed.

First report of colonization by Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae, Triatominae) in the Metropolitan Region of São Paulo, Brazil

“…Perlowagora -Szumlewicz et al (1988) demonstrated the ability of parasitic multiplication in this vector. In addition, several authors have mentioned the relationship between the presence of white-eared opossums (Didelphis albiventris and Didelphis marsupialis) and T. cruzi infection, emphasizing the importance of these animals as a link between the wild and the human environments (Santos Junior et al, 2013;Lima et al, 2012;Steindel et al, 2008;Fernandes et al, 1991).…”

Anti-complement activity in salivary glands and midgut of Chagas disease vector, Panstrongylus megistus (Hemiptera, Triatominae)

“…In this study, we confirmed those results. However, considering that P. megistus feeds on a wide range of vertebrate hosts 23 , being exposed to the deleterious potential of their complement systems, we have also investigated if the SGE could act on rodent and avian complement systems as well, which are usual bloodmeal sources for the vector but present an epidemiological role in Chagas disease transmission. Rats are common T. cruzi reservoirs, acting as sources of infection to P. megistus 27 .…”

“…Rats are common T. cruzi reservoirs, acting as sources of infection to P. megistus 27 . On the other hand, chickens are refractory to the parasite infection but are regularly reported as blood sources to P. megistus , thus are involved in the maintenance of vector populations 23 . As expected, P. megistus SGE significantly inhibited the lytic activity of rats and chickens, reflecting the importance of these inhibitors to the blood feeding process.…”

“…Panstrongylus megistus is an important Chagas disease vector well distributed in Latin America, especially in Brazil, where it is considered the most broadly distributed species throughout the country 22 . It is commonly associated with animals such as rodents, birds and marsupials, although in some parts of Brazil it occurs mainly in artificial ecotopes, with great capacity to invade and colonize human domicilies 23 , 24 . Moreover, P. megistus presents higher levels of anthropophily and natural infection with T. cruzi as compared to other triatomine vector species 25 , which accentuates its epidemiological role as a vector.…”

New cases of Chagas disease in a rural area of Northeast Brazilian

“…A recent study demonstrated high infestation rates of Panstrongylus megistus (17.5%) captured in households in one municipality in the South Central region of Sergipe (10) . Another study showed an association between Panstrongylus megistus and small wild mammals, and the authors suggested that the proximity between dwellings and natural foci vector infestation may have contributed to the presence of infected cases (11) .…”