Synanthropic triatomines as potential vectors of Trypanosoma cruzi in Central Brazil

Abstract INTRODUCTION: Chagas disease surveillance requires current knowledge on synanthropic triatomines. We analyzed the occurrence and Trypanosoma cruzi infection rates of triatomine bugs in central Brazil, during 2012-2014. METHODS: Triatomines were collected inside or around houses, and T. cruzi infection was determined by optical microscopy and conventional/quantitative polymerase chain reaction. RESULTS: Of the 2706 triatomines collected, Triatoma sordida was the most frequent species in Goiás State, whereas Panstrongylus megistus predominated in the Federal District. Parasites identified were T. cruzi, T. rangeli, and Blastocrithidia sp. CONCLUSIONS: P. megistus and T. sordida sustained the risk of T. cruzi transmission to humans in central Brazil.

Monitoramento da suscetibilidade de populações de Triatoma sordida Stål, 1859 (Hemiptera: Reduviidae) ao inseticida deltametrina, na região Centro-Oeste do Brasil / Monitoring the susceptibility of Triatoma sordida Stål, 1859 (Hemiptera: Reduviidae) to deltamethrin insecticide, in Central-Western Brazil

INTRODUÇÃO: Populações de Triatoma sordida Stål, 1859 foram investigadas quanto à suscetibilidade à deltametrina. MÉTODOS: Análise por meio de bioensaios por aplicação tópica em 11 populações de T. sordida procedentes dos Estados de Goiás, Mato Grosso e Mato Grosso do Sul. RESULTADOS: As estimativas de DL50 e RR50 demonstraram elevados níveis de suscetibilidade (DL50 < 1 e RR50 < 2). Entretanto, as análises do coeficiente angular da curva dose resposta revelaram que as populações de triatomíneos dos municípios de Firminópolis/GO, Posse/GO, Poxoréu/MT, Douradina/MS e Aparecida do Taboado/MS apresentam maiores probabilidades de evolução de resistência, portanto, mais propícias a tolerar o tratamento com deltametrina. CONCLUSÕES: Detectaram-se pequenas alterações de suscetibilidade e baixos níveis de resistência, porém as alterações temporais de suscetibilidade deverão ser continuamente monitoradas, a fim de nortear adequadamente as ações de controle dos vetores da DC.

INTRODUCTION: Triatoma sordida Stål, 1859 populations were investigated for susceptibility to deltamethrin. METHODS: This study aimed to analyze the resistance of 11 populations of insects from the States of Goiás, Mato Grosso and Mato Grosso do Sul by topical application bioassays. RESULTS: The estimated LD50 and RR50 showed high levels of susceptibility (LD50 < 1 and RR50 < 2). However, analysis of the slope of the dose response curve showed that the populations of insects in the towns of Firminópolis/GO, Posse/GO, Poxoréu/MT, Douradina/MS and Aparecida do Taboado/MS present great probability of evolving resistance and, thus, are more likely to tolerate treatment with deltamethrin. CONCLUSIONS: Small changes in susceptibility and low levels of resistance were detected, but the temporal changes of susceptibility should be continuously monitored to adequately guide the actions of vector-control of DC.