Avaliação da presença de triatomíneos e distribuição de DTUs Trypanosoma cruzi em diferentes mesorregiões do Rio Grande do Norte, Brasil

Abstract

This work evaluated the presence, distribution of triatomines and discrete typing units (DTUs) of Trypanosoma cruzi isolated from vectors in different mesoregions of the state of Rio Grande do Norte (RN). The captures of triatomines were carried out in rural areas of 21 municipalities, 71 rural communities e 345 domiciles in the period from 2015 to 2019. The genotyping was performed using the markers mitochondrial cytochrome oxidase subunit 2 (COII) gene, the region of the 24Salpha rRNA, spliced leader intergenic region (SL-IR). The infestation was observed in 7.5% (26/345) of households and 16.2% (56/345) of the surveyed households. The presence of nymphs in the home was observed in 94.7% (45/47) of the infested households, indicating colonization in this environment. A total of 1,084 triatomines were captured in anthropic and wild environments, with Triatoma brasiliensis (84.5%) being the most found species, followed by Triatoma pseudomaculata (14.9%), Panstrongylus lutzi (0.5%), Rhodnius nasutus (0.1%). T. brasiliensis was the only species found in the home, peridomicile and wild environment, and also the one that was able to infest the largest variety of infested ecotopes. Natural infection by T. cruzi was observed in 11.0% (96/872) triatomines, with T. brasiliensis being the species with the highest number of specimens (95.0%). Of the 96 infected triatomines, it was possible to isolate the parasite from 33 (34.4%) samples, all of which were genotyped. DTU I: haplotype A in COII, rDNA 2 e SL-IR with 150pb (51.5%; 17/33) was identified in the peridomicile infecting T. brasiliensis in the three studied mesoregions, and T. pseudomaculata, in the western mesoregion. DTU II: haplotype C in COII, rDNA 1, SL-IR with 150pb: (9.1%; 3/33) was found in T. brasiliensis only in the Central mesoregion, both in the home and in the wild. DTU III: haplotype B in COII, rDNA 2, SL-IR with 200pb:(27.3%, 9/33) was also found in all mesoregions, in the home area in the West mesoregion, in wild areas in the Center and the home area in Agreste. The proximity and even overlap of areas of occurrence of the genotypes were observed in several areas. In Caicó, this fact was evidenced by the detection of mixed infections with TcI and TcII. These results show that T. brasiliensis remains the species with the greatest epidemiological importance in the semi-arid region of RN, due to its wide geographical distribution, high degree of adaptation to different environments and ecotopes, high rate of natural infection by T. cruzi and the diversity of DTUs that can house, and reinforce the need for continuous entomological surveillance in the state, in order to prevent contact of this species with humans and domestic animals.