A darker chromatic variation of Rhodnius pallescens infected by specific genetic groups of Trypanosoma rangeli and Trypanosoma cruzi from Panama

Abstract

BackgroundRhodnius pallescens, the only species of this genus reported in Panama, has a wide geographical distribution and is associated with most cases of Chagas disease and human infections with Trypanosoma rangeli in this country. Thus far, no phenotypic variants of this triatomine have been registered. Similarly, genotyping of the trypanosomes that infect this vector has only been partially evaluated.ResultsA total of 347 specimens of R. pallescens were collected in Attalea butyracea palm trees located near a mountainous community of the district of Santa Fe, province of Veraguas. Bugs were slightly longer and had a darker coloration compared to that reported for this species. Infection rates for trypanosomes performed with three PCR analyses showed that 41.3% of the adult triatomines were positive for T. cruzi, 52.4% were positive for T. rangeli and 28.6% had mixed T. cruzi/T. rangeli infections. Based on cox2 analysis, TcI was the single T. cruzi discrete typing unit (DTU) detected, and a genetic variant of KP1(-)/lineage C was the only genetic group found for T. rangeli.ConclusionsA darker chromatic variation of R. pallescens predominates in a mountainous region of Panama. These triatomines show high trypanosome infection rates, especially with T. rangeli. Regarding T. rangeli genetic diversity, complementary studies using other molecular markers are necessary to better define its phylogenetic position.

Regional biogeography of microbiota composition in the Chagas disease vector Rhodnius pallescens

“…In the two Panama Oeste area locations (Las Pavas and Trinidad de las Minas) the topography is flatter with warmer temperatures (mean 27 °C). Of particular interest is that the evaluated specimens from Santa Fe District in northern Veraguas correspond with a darker chromatic variation of R. pallescens infected by specific genetic groups of T. rangeli and T. cruzi [44]. Although the genetic characteristics of this population have not been studied, the reported phenotypic differences and the differences found in their microbial composition could be explained by the presence of this dark chromatic variant in this geographical region.…”

“…We further collected 30 samples from four sites comprising three habitats located in Santa Fe District, Veraguas (8.509232° N, 81.077800° W) from 8–11 July 2017. The Santa Fe region has recently been described as a new endemic focus for Chagas disease in Panama, where a dark morph of R. pallescens predominates [43, 44]. All specimens were nymphs, primarily N3 and below (92%, 95% CI: 84.4–96.39%), with the exception of one male from Trinidad de las Minas (Additional file 1: Table S1).…”

“…The sylvatic behavior has complicated control efforts [42]. New endemic regions are still being described [43–45] and a darker chromatic variation of R. pallescens associated with distinct genetic groups of T. cruzi and T. rangeli has also been found recently in Santa Fe District, Panama [44].…”

Heterogeneity of Trypanosoma cruzi infection rates in vectors and animal reservoirs in Colombia: a systematic review and meta-analysis

“…Another triatomine species with a very high prevalence was R. pallescens with geographical predominance in the north-west part of the country (Caribbean region). This vector has been also associated with Attalea butyracea palms [63, 66–87], has been reported frequently in Costa Rica and Nicaragua [67] and it is considered the main vector in Panama [68, 69]. Importantly, this species has been found commonly circulating in areas of oral outbreaks in Colombia [37].…”

Mixed infections by different Trypanosoma cruzi discrete typing units among Chagas disease patients in an endemic community in Panama

“…Geographically, TcI predominates in the Andes region, in Central and North America, Mexico [ 23 – 25 ], presenting a sylvatic transmission cycle, mainly between marsupials and sylvatic triatomines [ 26 – 28 ]. This DTU is also associated with human infections reported from the United States [ 29 ], Mexico, Central America [ 30 , 31 ], and northern South America, having been detected in patients with cardiomyopathies from Venezuela [ 32 ] and Colombia [ 33 – 37 ].…”