Current situation of Chagas disease vectors (Hemiptera, Reduviidae) in Southern Rio Grande do Sul State, Brazil

Abstract

Chagas disease (CD) has been considered endemic in the South of Rio Grande do Sul (RS) State, Brazil. This study aimed at evaluating the occurrence of Trypanosoma cruzi vectors based on the main species captured in Southern Rio Grande do Sul State from 2008 to 2019. The study area comprised counties that belong to the 3 rd Regional Health Coordination (RHC) and to the 7 th RHC, whose headquarters are in Pelotas and Bage, respectively. The study was based on secondary data provided by the partnership between the Federal University of Pelotas, Rio Grande do Sul State (UFPel-RS) and the State Health Surveillance Center in RS (SCHS-RS). One thousand and four hundred triatomines were captured in the area supervised by the 3 rd RHC, mainly in Cangucu (37.7%), Piratini (22.4%) and Pinheiro Machado (15.1%), while, in the area supervised by the 7 th RHC, the largest number of triatomines was captured in Lavras do Sul (64.15%). In both areas, Triatoma rubrovaria (90.6%) and Panstrongylus tupynambai (7.4%) were the most common species. Most were captured inside households but T. cruzi -positive insects were not found in the period under study. The results of this study show that, in Southern Rio Grande do Sul State, there is still a high rate of triatomine household invasion and dispersal, mainly by T. rubrovaria . Thus, the entomological surveillance should be maintained with the participation of the population and further studies should be deepened in the area.

Triatoma rubrovaria (Hemiptera, Reduviidae, Triatominae) in the Pampa biome, Brazil: a retrospective study of its occurrence and abundance

“…The data analysis carried out by this study shows that occurrences of T. rubrovaria decreased over time. Other studies of CD vectors in RS reported similar results 13 , 14 . The decrease may be the result of advances in T. infestans control measures, the main objective of the Programa de Controle da Doenca de Chagas (PCDCh – Chagas Disease Control Program), which has been working in the whole country to plan activities of active research, chemical control and housing improvement since 1975 9 , 15 .…”

“…It shows an important prevalence of CD among this population, since the disease’s main prevalence among blood donors in Brazil was 0.21% 12 . T. rubrovaria remains the epidemiologically most disperse and relevant species in RS 13 .…”

Seroprevalence of Trypanosoma cruzi infection in blood donors in the extreme South of Brazil

“…In addition, Baruffa and Alcântara 13 found the most prominent focus of T. infestans in houses in Canguçu and Piratini, where several cases of acute CD were registered. The study conducted by Bianchi et al 4 also corroborates these results since they noted the largest number of captured triatomines in Canguçu, where 37.7% of all insects, mainly Triatoma rubrovaria, captured in 22 southern Brazilian cities were found. Serological markers were also evaluated in those seropositive for CD.…”

“…Triatoma infestans, a species that is better adapted to households, is regarded as the main vector of CD. However, even though this vector was eliminated from southern RS, other species of triatomines have persisted in rural houses 3,4,5 .…”

Anxiety, depression, and memory loss in Chagas disease: a puzzle far beyond neuroinflammation to be unpicked and solved*

“…Despite the population decrease of vectors, due to control and surveillance programs, 10 there are still reports of a high rate of home invasion by CD vectors in endemic regions. 11 The most important form of CD transmission is still the vector-born (either via the lesion resulting from the bite, or via the ocular or oral mucosa), blood-borne, and congenital. 10 Presently, the oral form of CD transmission is the most mentioned in Brazil, occurring via ingestion of food, mainly fruit juices (açai, sugar cane, guava, cashew) contaminated with debris or excreta of the vector.…”