Triatomine fauna in the state of Bahia, Brazil: What changed after 40 years of the vector-control program?

ABSTRACT Background: Neglected tropical diseases are a growing threat to global health, and endemic Chagas disease has emerged as one of the most important health problems in America. The main strategy to prevent Trypanosoma cruzi transmission is chemical control of vectors. This study presents a descriptive analysis of synanthropic triatomines before and after the implementation of a vector-control program in Bahia, Brazil. Methods: Descriptive analysis and geospatial statistics were performed on triatomine data, (1) the relative abundance and (2) proportional spatial distribution, from Bahia during two periods: (A) 1957 to 1971 and (B) 2006 to 2019. Results: We observed a decrease in the relative abundance of Panstrongylus megistus (A: n=22.032, 61.9%; B: n=1.842, 1.0%) and Triatoma infestans (A: n=1.310, 3.7%; B: n=763, 0.43%), as well as an increase in the relative abundance of T. sordida (A: n=8.314, 23.4%, B: n=146.901, 81.6%) and T. pseudomaculata (A: n=894, 2.5%, B: n=16.717, 9.3%). Conclusions: Our results indicate a clear reduction in the occurrence of P. megistus and T. infestans (last record in 2015) and an increase in the relative abundance and geographical distribution of T. sordida and T. pseudomaculata after 40 years of the vector-control program. The high frequency of other triatomine species in the municipalities of the state of Bahia and their abundance in recent years highlight the need to reinforce permanent entomological surveillance actions to prevent Chagas disease.

Caracterização molecular de cepas de Trypanosoma Cruzi isolada na zona urbana da cidade de Salvador/BA / Molecular characterization of Trypanosoma cruzi isolated from strains in the urban area of the city of Salvador / Ba

A Doença de Chagas é uma infecção parasitária causada pelo protozoário flagelado Trypanosoma cruzi. As cepas de T. cruzi se constituem de uma população heterogênea, apresentando várias subpopulações. Essas populações circulam entre animais vertebrados domésticos, silvestres e humanos, além de insetos vetores. Devido a essas múltiplas relações, o T. cruzi demostra uma grande variedade biológica, genética, bioquímica e imunológica. A caracterização das cepas de T. cruzi pode utilizar várias metodologias que pode ter foco biológico, bioquímico, isoenzimático e molecular. Dentre essas, a molecular vem ganhando destaque devido a rapidez, sensibilidade e precisão do método. Deste modo, com a presente pesquisa o objetivo foi caracterizar molecularmente as cepas de Tripanosoma cruzi (Chagas 1909) isoladas em vetores e reservatórios na zona urbana de Salvador. Foram incluídas neste estudo amostras de T. cruzi isoladas de triatomíneos e reservatórios provenientes de diversas localidades da cidade de Salvador, capturados entre Julho de 2007 e Junho de 2011, perfazendo um total de 4 anos de amostragem. Adotamos a técnica de tipagem molecular do T. cruzi sugerida por Zingales et al. (2009) em sistema de eletroforese capilar. Das 930 amostras de triatomíneos avaliados, 99,35% da espécie Triatoma tibiamaculata, 482 amostras (52%)...

Chagas disease is a parasitic infection caused by the flagellate protozoan Trypanosoma cruzi. The T. cruzi strains constitute a heterogeneous population, with several subpopulations. These populations move between domestic vertebrate animals, wildlife and humans, and insect vectors. Because of these multiple relationships, T. cruzi demonstrates great biological diversity, genetic, biochemical and immunological. The characterization of T. cruzi strains can use various methodologies that may have biological, biochemical, and molecular isoenzyme focus. Among these, the molecular been gaining attention due to speed, sensitivity and precision of the method. Thus, the present study the objective was to characterize molecularly strains of Trypanosoma cruzi (Chagas 1909) isolated in vectors and reservoirs in the urban area of Salvador. Were included in this study T. cruzi samples of insects and shells from different localities of the city of Salvador, captured between July 2007 and June 2011, a total of four years of sampling. We adopt molecular typing technique of T. cruzi suggested by Zingales et al. (2009) in a capillary electrophoresis system. Of the 930 samples evaluated triatomine 99.35% of Triatoma tibiamaculata, 482 samples (52%)...

Presence of triatoma tiblamaculata (pinto) nymphs in peridomiciles, in Salvador, Bahia

Chagas disease is associated with the domiciliation of infected vectors migrating from their natural ecotopes. The appearance of nymphs in the peridomicile, in Salvador, Bahia, confirms the need for epidemiological surveillance. The vectors were captured from 2006 to 2009, by the population and by epidemiological field agents with the Chagas Disease Control Program. Three hundred and sixty two nymphs of the species Triatoma tibiamaculata (Pinto, 1926) were captured in the peridomicile and 13.5 por cento of these nymphs were infected with Trypanosoma cruzi (Chagas, 1909). Nymphs were near the houses, a possible risk for colonization. Surveillance of the peridomicile is an important element to prevent colonization by disease vectors...

A doença de Chagas está associada à domiciliação de vetores infectados provenientes dos ecótopos naturais. O surgimento de ninfas no peridomicílio em Salvador, Bahia, reafirma a necessidade de vigilância epidemiológica. Os vetores foram capturados de 2006 a 2009 pela população e por agentes de endemias no contexto do Programa de Controle da Doença de Chagas. Foram capturadas 362 ninfas da espécie Triatoma tibiamaculata (Pinto, 1926) no peridomicílio, 13,5 porcento das quais estavam infectadas com T. cruzi (Chagas, 1909). As ninfas estão próximas aos domicílios, o que representa um possível risco de colonização. A vigilância no peridomicílio constitui importante fator de prevenção da colonização de vetores da doença...