Species-specific differences in the egg exochorium of the sympatric taxa Triatoma costalimai and Triatoma jatai (Hemiptera: Reduviidae: Triatominae).

Triatoma costalimai and Triatoma jatai are related species, which occur in sympatry in Paranã, Tocantins, Brazil, in rocky outcrops and in peridomicile and intradomicile environments. This study compared morphologic and morphometric aspects of the eggs of these species using optical microscopy (OM) and scanning electron microscopy (SEM). Operculum cells (OP) and egg body (EB) were drawn and photographed, their surfaces were measured, and spots were quantified. Statistical analyses were performed using ANOVA and t-tests. OM showed an egg exochorium with spots in T. costalimai and a predominance of short lines in T. jatai. We found significant differences in egg length and width, which were larger in T. costalimai. SEM analysis showed that the operculum of both species had cells with straight and/or rounded rims, with a smooth aspect, random spots, and predominantly pentagonal shape. In the EB, hexagonal cells were predominant, with indices exceeding 60% in both species. Triatoma costalimai cells were flat, with a discrete definition of the rims, whereas T. jatai cells were smooth with well-defined rims. Statistical tests showed significant differences for EB, where T. costalimai cells were larger and have more spots than T. jatai. The eggs can thus be differentiated, thereby contributing to integrative taxonomy.

External female genitalia of Triatoma jatai, Triatoma costalimai and Triatoma williami (Hemiptera: Reduviidae: Triatominae).

BACKGROUND: Taxonomic identification of triatomines is generally performed based on aspects of their external morphology. However, the use of a multidisciplinary approach, considering morphological aspects of the external genitalia, morphometry, genetics, and phylogeography has been suggested, especially for similar and/or cryptic species. The rupestral species Triatoma jatai Gonçalves et al., 2013, Triatoma costalimai Verano & Galvão, 1959 and Triatoma williami Galvão et al., 1965, which are morphologically similar, have been found naturally infected with Trypanosoma cruzi (Chagas, 1909) in wild, peridomestic, and intradomestic environments, representing a risk of new outbreaks of Chagas disease. This study presents morphological description complementation of these species, with an emphasis on the structures of the female external genitalia, using scanning electron microscopy. METHODS: The females of T. jatai and T. costalimai (n = 10 of each) were captured in the Brazilian municipalities of Paranã and Aurora do Tocantins and were identified with the use of a dichotomous key for the Matogrossensis subcomplex. Females of T. williami (n = 5), were obtained from a laboratory colony. The females were cut transversely at the sixth abdominal segment and examined under scanning electron microscopy (SEM) at the Oswaldo Cruz/Fiocruz Institute Electronic Microscopy Platform. RESULTS: It was possible to differentiate the three species based on the characteristics of urotergites VII, VIII and IX and urosternite VII, as well as the genital plaques, gonocoxites, and gonapophyses. To our knowledge, morphological differences in the spines present on gonapophysis 8 in triatomines are described here for the first time. CONCLUSIONS: The results show that external genitalia of females are useful structures to differentiate T. costalimai, T. jatai and T. williami. SEM analysis contributes to and corroborates, together with other tools morphological and molecular, the distinction of the three species.

Triatoma costalimai Naturally Infected by Trypanosoma cruzi: A Public Health Concern.

The rupestrian Triatoma costalimai species has been found infected by Trypanosoma cruzi in wild, peridomicile, and intradomicile environments in the municipality of Aurora do Tocantins, Tocantins, Brazil. Proximity between rock outcrops increases the risk of vector transmission of Chagas disease via this species. This work describes a focus of colonization by T. costalimai specimens infected by T. cruzi in rock outcrops located in an urban area in this municipality. Parasitological examination of feces from the collected specimens, axenic cultivation of T. cruzi-positive samples, and genetic characterization of the isolates were performed. Nymph and adult specimens were collected with a high infection prevalence (64.5%) for T. cruzi discrete type unit (DTU I). Participation of the T. costalimai species in the wild cycle of T. cruzi in rock outcrops located in an urban area demonstrates the need for entomological surveillance and control of vector transmission of Chagas disease in the municipality of Aurora do Tocantins, Tocantins.

Mitochondrial Genes Reveal Triatoma jatai as a Sister Species to Triatoma costalimai (Reduviidae: Triatominae).

Triatoma jatai was described using a set of morphological structures from specimens collected in Paranã municipality of Tocantins State, Brazil. Under a Bayesian framework and using two mitochondrial genes (16S and COI), phylogenetic analysis recovered T. jatai as a sister species to Triatoma costalimai with higher genetic distances than between other well-recognized species. Our results agree with previous suggestions based on morphometric analysis. In the light of the non-monophyly of Matogrossensis subcomplex, the inclusion of T. jatai shall be considered for reevaluating this group.

Molecular epidemiology of hepatitis A virus in Brazilian Amazon.

BACKGROUND: Hepatitis A virus (HAV) is highly endemic in the Amazon. However, few data are available regarding HAV genotypes circulating in this region of the world. The aim of the present study was to characterize genetically HAV isolates circulating in the Brazilian part of the Amazon. METHODS: Blood samples were collected from 134 IgM anti-HAV positive patients (sporadic cases). Viral RNA was extracted and the virion protein (VP)1/2A junction region of the HAV genome was successfully amplified by reverse transcription-polymerase chain reaction for 81 samples (60.4%). Nucleotide sequences (210 bp) of the 81 isolates were determined. RESULTS: All HAV samples were from genotype I, with 78 (96.3%) belonging to subgenotype IA and three (3.7%) to subgenotype IB. By phylogenetic analysis, it was shown that 72/78 of the subgenotype IA isolates formed a cluster separated from the other South American HAV isolates previously characterized. CONCLUSION: The present study provides valuable new data on the genetic relatedness of HAV from the Amazon. Subgenotype IB circulates in the Brazilian Amazon but the predominant genotype is 1A, similar to what occurs in most South American countries.