The connection between Trypanosoma cruzi transmission cycles by Triatoma brasiliensis brasiliensis: A threat to human health in an area susceptible to desertification in the Seridó, Rio Grande do Norte, Brazil

Abstract

An outbreak of Chagas disease, possibly involving its vector Triatoma brasiliensis brasiliensis, was identified in the state of Rio Grande do Norte (RN). Given the historical significance of this vector in public health, the study aimed to evaluate its role in the transmission dynamics of the protozoan Trypanosoma cruzi in an area undergoing desertification in the Seridó region, RN, Brazil. We captured triatomines in sylvatic and anthropic ecotopes. Natural vector infection was determined using parasitological and molecular methods and we identified discrete typing units (DTUs) of T. cruzi by analyzing the COII gene of mtDNA, 24Sα rDNA, and mini-exon gene. Their blood meals sources were identified by amplification and sequencing of the mtDNA cytochrome b gene. A total of 952 T. b. brasiliensis were captured in peridomestic (69.9%) and sylvatic ecotopes (30.4%). A wide range of natural infection rates were observed in peridomestic (36.0% - 71.1%) and sylvatic populations (28.6% - 100.0%). We observed the circulation of TcI and TcII DTUs with a predominance of Tcl in sylvatic and peridomestic environments. Kerodon rupestris, rocky cavy (13/39), Homo sapiens, human (8/39), and Bos taurus, ox (6/39) were the most frequently detected blood meals sources. Thus, Triatoma b. brasiliensis is invading and colonizing the human dwellings. Furthermore, high levels of natural infection, coupled with the detection of TcI and TcII DTUs, and also the detection of K. rupestris and H. sapiens as blood meals sources of infected T. b. brasiliensis indicate a risk of T. cruzi transmission to human populations in areas undergoing desertification.

Estimating the genetic structure of Triatoma dimidiata (Hemiptera: Reduviidae) and the transmission dynamics of Trypanosoma cruzi in Boyacá, eastern Colombia

“…It is important to highlight that the result we obtained for T . dimidiata are similar to values reported for other epidemiologically relevant triatomine species in the Americas (also including some secondary vectors): Rhodnius prolixus (73.3%, 55.8%) [ 5 , 48 ], Panstrongylus geniculatus (56%, 87.5%, 70.6%) [ 5 , 48 , 53 ], Triatoma maculata (67.6%) [ 5 ], Rhodnius pallescens (45.9%) [ 5 ], Rhodnius pictipes (87.5%) [ 4 ], Mepraia spinolai (14–76%) [ 54 , 55 ] and Triatoma brasiliensis (peridomestic: 36–71%, sylvatic: 28–100%) [ 56 ]. This implies that T .…”

“…We found an infection rate of 70.31% in 2019, slightly more than double what was reported for the preceding years in the same department [30]. It is important to highlight that the result we obtained for T. dimidiata are similar to values reported for other epidemiologically relevant triatomine species in the Americas (also including some secondary vectors): Rhodnius prolixus (73.3%, 55.8%) [5,48], Panstrongylus geniculatus (56%, 87.5%, 70.6%) [5,48,53], Triatoma maculata (67.6%) [5], Rhodnius pallescens (45.9%) [5], Rhodnius pictipes (87.5%) [4], Mepraia spinolai (14-76%) [54,55] and Triatoma brasiliensis (peridomestic: 36-71%, sylvatic: 28-100%) [56]. This implies that T. dimidiata might represent a risk for T. cruzi transmission because they move around significantly, feeding on many domestic and sylvatic reservoirs (as we will discuss later) where they obtain the parasite, which might represent a higher risk for humans.…”

Wild mammals involved in the transmission of Trypanosoma cruzi and food sources of Triatoma sherlocki in an endemic region of northeastern Brazil

“…In the state of Rio Grande do Norte, also in the northeastern region of Brazil, K. rupestris is also one of the main sources of food for triatomines captured in anthropic and wild environments of preserved areas and in the process of desertification. With the aggravating fact that these triatomines present high infection rates by T. cruzi , which reinforces the possible role of this rodent as a reservoir of the protozoan (Almeida et al, 2016; Lima‐Neiva et al, 2021). Lilioso et al (2020) were the first to prove a close association of rodents of the Caviidae family (70%; 127/181) [mainly Galea spixii (64%; 116/181), but also K. rupestris (6%; 11/181)] with triatomines of the species T. brasiliensis , captured mainly in peridomiciliary environments (66%; 84/127).…”

Morphological Stasis in Time? A Triatoma brasiliensis brasiliensis Study Using Geometric Morphometrics in the Long Run

“…Triatoma brasiliensis brasiliensis is one of the most important vectors of Chagas disease in the semiarid regions in Brazil [ 6 , 7 , 12 ] and occurs in six states: Ceará, Maranhão, Paraíba, Pernamb uco, Piauí, and Rio Grande do Norte. This species displays eclectic feeding behavior and can inhabit different ecotopes, besides presenting one of the highest rates of T. cruzi infection and high rates of intradomiciliary infestation [ 7 , 8 , 13 , 14 , 15 , 16 , 17 , 18 ]. The epidemiologic importance of T. b. brasiliensis has motivated a variety of studies, placing it as one of the most studied species of triatomines.…”

“…The epidemiologic importance of T. b. brasiliensis has motivated a variety of studies, placing it as one of the most studied species of triatomines. The substantial amount of information available on its morphological, behavioral, biological, and eco-epidemiologic aspects has been providing subsides to improve the strategies of Chagas disease control programs in endemic areas [ 7 , 8 , 12 , 18 , 19 , 20 , 21 , 22 ].…”