Enzootic transmission of Trypanosoma cruzi and T. rangeli in the Federal District of Brazil

Abstract

SUMMARYThe Federal District of Brazil (DF) lies within the Cerrado biome, where open shrubland (savannas) is interspersed with riverside gallery forests and permanent swamps (veredas). Trypanosoma cruzi-infected native triatomines occur in the area, but the enzootic transmission of trypanosomatids remains poorly characterized. A parasitological survey involving sylvatic triatomines (166 Rhodnius neglectus collected from Mauritia flexuosa palms) and small mammals (98 marsupials and 70 rodents, totaling 18 species) was conducted in 18 sites (mainly gallery forests and veredas) of the DF. Parasites were isolated, morphologically identified, and characterized by PCR of nuclear (mini-exon gene) and kinetoplast DNA (kDNA). Six R. neglectus, seven Didelphis albiventris and one Akodon cursor were infected by trypanosomes; wild reservoir infection is documented for the first time in the DF. kDNA PCR detected T. cruzi in five R. neglectus and mini-exon gene PCR revealed T. cruzi I in isolates from D. albiventris. Parasites infecting one bug yielded T. rangeli KP1+ kDNA amplicons. In spite of the occurrence of T. cruzi-infected D. albiventris (an important wild and peridomestic reservoir) and R. neglectus (a secondary vector displaying synanthropic behavior), a low-risk of human Chagas disease transmission could be expected in the DF, considering the low prevalence infection recorded in this work. The detection of T. rangeli KP1+ associated with R. neglectus in the DF widens the known range of this parasite in Brazil and reinforces the hypothesis of adaptation of T. rangeli populations (KP1+ and KP1-) to distinct evolutionary Rhodnius lineages.

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

“…Rhodnius neglectus is widespread in central Brazil and has an important role in enzootic transmission of T. cruzi 5,7 . Apart from the invasion of adults in domiciles 48 , there is evidence of household infestation of R. neglectus (with bugs occasionally establishing breeding colonies) in the States of Minas Gerais, Goiás, and São Paulo 18,49,50 .…”

“…), which are frequently infected with T. cruzi, thus justifying high infection indices when compared with other species of triatomines 26,28,29 . A study on T. cruzi reservoirs in DF showed that specimens of D. albiventris are responsible for maintaining enzootic circulation of the parasite in the region, where 33% of these mammals were infected 5 . However, P. megistus has varied feeding habits, also feeding on birds, dogs, cats, rodents, cattle, goats, pigs, and humans 17,27,30 .…”

“…Other studies have shown enzootic circulation of T. cruzi and T. rangeli in gallery forests. Indices of natural infection with T. cruzi were 33% for mammalian reservoir (Didelphis albiventris) and 9% for R. neglectus 5 , thus showing the need to maintain entomological surveillance and to monitor the invasion and/or colonization of wild triatomines in domestic environments.…”

Biologia comparativa e comportamento alimentar de Rhodnius neglectus e Rhodnius robustus (Triatominae) sob condições de laboratório

“…R. neglectus é uma espécie característica do cerrado no Brasil central com um papel importante na transmissão enzoótica de Trypanosoma cruzi e T. rangeli 6 . Além da invasão de adultos nos domicílios 7 , existem evidências de formação de colônias domiciliares de R. neglectus nos Estados de Minas Gerais, São Paulo e Goiás [8][9][10] , sendo considerado como um vetor secundário na transmissão da doença de Chagas.…”

Synanthropic triatomines as potential vectors of Trypanosoma cruzi in Central Brazil

“…Thaís Tâmara Castro Minuzzi-Souza [1] , Nadjar Nitz [2] , César Augusto Cuba Cuba [1] , Marcelo Santalucia [3] , Monique Knox [4] , Luciana Hagström [2] , Camilla Bernardes Furtado [1] , Tamires Emanuele Vital [2] , Marcos Takashi Obara [1] , Mariana Machado Hecht [2] and Rodrigo Gurgel-Gonçalves 5,6 .…”