The results of this study indicate that the persistence of residual foci of T. infestans in Bahia and Rio Grande do Sul is not related to insecticide resistance but may be associated with operational failures. In Rio Grande do Sul, we must consider the possibility of continuous reinfestation by Argentinian individuals, which justifies active and efficient epidemiological surveillance.

Introduction: This retrospective study conducted from 2001 to 2018 investigated the residual foci of Triatoma infestans infestation in Rio Grande do Sul, Brazil. Methods: The data were obtained via entomological surveillance and the distribution of vector occurrence. The coverage of active research was mapped. Results: The largest coverage rate for active research was observed in the northwest region of the total of 515,081 domiciles researched. Most T. infestans specimens were captured in the peridomicile. Conclusions: Infestation has decreased significantly since 2008, and T. infestans has not been captured since 2015.

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.

Several studies have shown that the population has relatively little information regarding Chagas disease (CD) and its vectors; however, this knowledge is relevant because community participation is vital for success in disease control actions. For this reason, and due to the lack of audiovisual material on this subject in the country, this study focused on making an educational documentary on CD and its vectors, which could be available to the population for free. The video preparation was divided into three phases: Pre-production, Production and Post-production. The site chosen for shooting was northwestern Rio Grande do Sul State due to the Triatoma infestans vector persistence in recent decades in that area. A documentary was obtained which addresses relevant CD aspects, such as its history, transmission, major vectors and biology, phases of the disease and, in particular, how to inspect the intra-domiciliary and peri-domiciliary areas in search of triatomine bugs or "kissing bugs". The use of videos as an educational tool helps broadcast information; therefore, this documentary is a public use tool, which aims to promote the control and prophylaxis of CD and its vectors.

In spite of long-term efforts to eliminate Triatoma infestans (Klug 1834) from Brazil, residual foci still persist in the states of Bahia and Rio Grande do Sul. Data on the genetic variability and structuring of these populations are however lacking. Using nine microsatellite loci, we characterized one residual T. infestans population from Bahia and four from Rio Grande do Sul, and compared them with bugs originally from an older focus in São Paulo; 224 bugs were genotyped. The number of alleles per locus ranged from 5 to 11. Observed and expected heterozygosities per locus ranged, respectively, from 0 to 0.786 and from 0 to 0.764. Significant departures from Hardy-Weinberg equilibrium, mainly due to heterozygote deficits, were detected in all loci and in most populations. Global indices estimated by AMOVA were: Fis was 0.37; Fst was 0.28; and Fit was 0.55; overall indices with p = 0.00 indicated substantial differentiation. Inter-population Fst ranged from 0.118 to 0.562, suggesting strong genetic structuring and little to no gene flow among populations. Intra-population Fis ranged from 0.301 to 0.307. Inbreeding was apparent in all populations except that from Bahia-which might be either linked by gene flow to nearby unsampled populations or part of a relatively large local population. The overall pattern of strong genetic structuring among pyrethroid-susceptible residual T. infestans populations suggests that their persistence is probably due to operational control failures. Detection and elimination of such residual foci is technically feasible and must become a public health priority in Brazil.