Entomological surveillance of Chagas disease in Berilo municipality, Jequitinhonha Valley, State of Minas Gerais, Brazil

Abstract

This study aimed to evaluate the Chagas Disease Control Program which has operated since 1982 in the municipality of Berilo in the Jequitinhonha Valley, Minas Gerais, Brazil, based on evaluation of 5,242 domiciliary units (DUs) and 7,807 outbuildings over an eight-year period of epidemiological surveillance implanted in 1997. A total of 391 triatomines (280 Panstrongylus megistus and 111 Triatoma pseudomaculata) were captured, indicating the continued predominance of the former species. However, Triatoma pseudomaculata is clearly becoming more important in this region, with intradomiciliary colonies being detected in recent years. Entomological parameters, such as dispersion (17%) and intradomiciliary infestation (0.15%) indices, are compatible with the results of the epidemiological surveillance. The majority of DUs were of construction type A (plaster over bricks) or C (plaster over adobe). Twenty-five percent of the inhabitants of the DUs infested by triatomines were reactive in ELISA, IHA and IIF tests for Trypanosoma cruzi antigens. RESUMOO objetivo deste estudo foi avaliar o Programa de Controle de doença de Chagas instalado desde 1982 no município de Berilo, Vale do Jequitinhonha, MG, Brasil, baseado na avaliação de 5.242 unidades domiciliares e 7.807 anexos após oito anos de implantação da vigilância epidemiológica que ocorreu em 1997. Um total de 391 triatomíneos (280 Panstrongylus megistus e 111 Triatoma pseudomaculata) foram capturados, indicando o contínuo predomínio da primeira espécie. No entanto, Triatoma pseudomaculata está claramente se tornando mais importante nesta região, com colônias intradomiciliares sendo detectadas recentemente. Parâmetros entomológicos, como os índices de dispersão (17%) e infestação intradomiciliar (0,15%), são compatíveis com a fase de vigilância epidemiológica. A maioria das UDs apresenta padrão de construção tipo A (tijolo com reboco) e A maioria das UDs apresenta padrão de construção tipo A (tijolo com reboco) e C (adobe com reboco). Dentre os habitantes das unidades domiciliares infestadas por triatomíneos, 25% apresentavam testes reativos na ELISA, HAI e IFI para antígenos de Trypanosoma cruzi. Palavras-chaves: Vigilância entomológica. Doença de Chagas. Panstrongylus megistus. Triatoma pseudomaculata. Inquérito sorológico.

Occurrence of synanthropic triatomines (Hemiptera: Reduviidae) in the Federal District of Brazil

“…In the northeast of Brazil T. pseudomaculata has great importance for epidemiological surveillance of Chagas disease, its being the most frequent species after T. brasiliensis 15,42 . Some studies have suggested that the increasing presence of T. pseudomaculata in the domiciliary environment is related to climate change, deforestation, and cropland expansion 25,44 , which could explain the higher frequency of this species in the rural areas of Planaltina and Paranoá, observed in the present study.…”

“…In the northeast of Brazil T. pseudomaculata has great importance for epidemiological surveillance of Chagas disease, its being the most frequent species after T. brasiliensis 15,42 . Some studies have suggested that the increasing presence of T. pseudomaculata in the domiciliary environment is related to climate change, deforestation, and cropland expansion 25,44 , which could explain the higher frequency of this species in the rural areas of Planaltina and Paranoá, observed in the present study.Regardless of the fact that it has remained the most collected species in cerrado areas of Brazil for the past years 18,45-47 , T. sordida presents a low risk of transmission of T. cruzi to humans because of its peridomiciliary behavior and marked ornithophily 15,34,[46][47] . Some studies show that zones of higher occurrence of T. sordida correspond to those of higher and older farm exploration 33 , which may justify the higher frequency of this species in Planaltina.…”

“…In the south of Brazil it occurs mainly in wild ecotopes 16,22 , unlike in the southeast and northeast regions where P. megistus has greater epidemiological importance for occupying artificial ecotopes 15,17,[23][24][25] . Specimens of P. megistus prefer tree hollows in arboreal habitats 26,27 , and they feed on marsupials (Didelphis spp.…”

“…This species was often found in domiciles in Planaltina and Paranoá, and in some of these domiciles nymphs were collected, indicating colonization. Even though T. pseudomaculata is more frequent in peridomicile and usually feeds on birds, the colonization in domiciles has been observed in Sobral, Ceará, and Berilo, Minas Gerais, suggesting adaptation of this species in this environment 25,43 . In the northeast of Brazil T. pseudomaculata has great importance for epidemiological surveillance of Chagas disease, its being the most frequent species after T. brasiliensis 15,42 .…”

Occurrence and distribution of triatomines (Hemiptera: Reduviidae) in municipalities of the Northeastern region of Minas Gerais State, Brazil

“…This fact may be associated to environmental (deforestation, urban expansion) and social (migration, electrifi cation of rural domiciles) changes that occurred in the area, as observed for T. pseudomaculata in a municipality of this region, where the presence of the species seems to be related to the changes in primary land coverage and aridifi cation (14) .…”