Estudo retrospectivo de Triatoma rubrovaria (Blanchard, 1843) no bioma Pampa, Brasil

Abstract

Vector-borne diseases occur more frequently in tropical and subtropical areas, especially in vulnerable situations. Some representatives of the Triatominae subfamily are vectors of Chagas disease (CD) in Brazil, with about ten species of epidemiological importance. Triatoma rubrovaria is persistently captured in rural areas of some regions of Rio Grande do Sul (RS), Brazil, being a species adapted to the Pampa biome. There is a need to describe its distribution in detail in this biome, in order to verify the current potential for CD transmission. The objective of this study was to investigate the occurrences of T. rubrovaria in the Pampa biome and in transition areas (Pampa/Atlantic Forest) of RS. The collection of information about the vector was based on secondary data provided by the State Health Surveillance Center (CEVS) in RS, and the following aspects were taken into account: year of capture; County; plant formation; number of specimens captured; invasion or domiciliation; notification in the intra-domicile, peri-domicile or both; infection for T. cruzi. The period evaluated was from 2009 to 2020; the survey covered 109 municipalities located in the Pampa biome and 98 in transition areas. Data tabulation was performed using the Microsoft Excel® program. Values were expressed as frequency and percentage and statistical comparison between variables was performed using the chi-square test (χ2). In the Pampa biome, 51 municipalities reported the presence of the vector in transition areas 19, the total number of specimens captured was 2,747. The Pampa biome presented 85% of the occurrences for T. rubrovaria, and 1.2% of the specimens were positive for T. cruzi. The 1st and 2nd biennia (2009-2010 and 2011-2012) concentrated 64.6% of T.rubrovaria catches. The municipalities in Pampa with the highest number of copies were Alegrete and Canguçu, with more than 250 notifications, followed by Piratini (151 – 250). For the transition areas, Roque Gonzales, Santiago and Santana da Boa Vista stood out, with occurrences between 50 – 150 specimens. There were more captures inside the home than outside the home; more adults than nymphs were found. T. rubrovaria is better adapted to the Pampa biome, and although the positivity found for T.cruzi is low, the species continues to show epidemiological importance in the region, being detected in 70 (33.8%) of the 207 evaluated municipalities, which fully justifies the maintenance of surveillance.