Evaluation of resistance to pyrethroid and organophosphate adulticides and kdr genotyping in Aedes aegypti populations from Roraima, the northernmost Brazilian State.

BACKGROUND: Roraima, the northernmost State in Brazil, borders Venezuela and Guyana. Although mostly covered by the tropical forests, the urban centers of this state are highly infested with Ae. aegypti and are endemic for dengue, Zika and chikungunya. We accessed the insecticide resistance status of Ae. aegypti populations from the capital Boa Vista, two cities on international borders (Pacaraima and Bonfim) and Rorainópolis bordering Amazonas State, in order to evaluate the chemical control efficacy in these localities. METHODS: Tests with World Health Organization (WHO)-like tubes impregnated with the pyrethroid deltamethrin (0.05% and 0.12%) and the organophosphate malathion (0.7%) were conducted with Ae. aegypti from Boa Vista, Pacaraima, Bonfim and Rorainópolis, collected in 2016 and 2018. Genotyping of kdr mutations, related to resistance to pyrethroids, was performed for the SNP variations at sites 1016 and 1534 of the voltage gated sodium channel gene (NaV) with a TaqMan qPCR approach. RESULTS: Aedes albopictus was absent in our collections, and therefore only Ae. aegypti was tested. All Ae. aegypti populations were susceptible to 0.7% malathion in 2016; however, mortality dropped to under 90% in Bonfim and Pacaraima populations in 2018. All populations were resistant to 0.05% deltamethrin in both years. The time that 50% of females suffered knockdown (KdT50) under exposure to 0.05% deltamethrin was 3.3-5.9-fold longer in mosquitoes from the natural populations compared to the susceptible Rockefeller strain. Only the Pacaraima population (2018) remained resistant to 0.12% deltamethrin. Kdr genotyping revealed the absence of the wild-type NaVS haplotype (1016Val + 1534Phe) in the populations from Roraima, indicating that all tested insects had a genetic background for pyrethroid resistance. The double kdr NaVR2 haplotype (1016Ile + 15434Cys) was present in higher frequencies in all populations except for Rorainópolis, where this haplotype seems to have arrived recently. CONCLUSIONS: These results are important for the knowledge about insecticide resistance status of Ae. aegypti populations from Roraima and will help improve vector control strategies that may be applied to diverse localities under similar geographical and urban conditions.

Persistent chikungunya arthritis in Roraima, Brazil.

BACKGROUND: The Amazon region of Brazil experienced a large epidemic of East Central South African (ECSA) chikungunya virus (CHIKV) in 2017 and continuous transmission of CHIKV persists. The impact of chronic arthritis caused by ECSA CHIKV is unknown. OBJECTIVE: The study aim was to describe the duration, severity, and characteristics of CHIKV arthritis in Roraima, Brazil, in comparison with local controls to further understand the long-term rheumatologic impact of ECSA CHIKV infection. METHODS: We performed a cross-sectional analysis comparing clinical arthritis outcomes among 40 cases with chronic (> 3 months) arthritis attributed to their CHIKV disease (n = 40) with control participants who were exposed to CHIKV but did not develop chronic arthritis (n = 40), rheumatoid arthritis controls (n = 40), and healthy controls lacking CHIKV exposure and arthritis (n = 40). FINDINGS: Our primary finding is that over 2 years post-infection, patients report moderate arthritis disease severity comparable with rheumatoid arthritis with the most significant impact on decreased quality of life from pain. MAIN CONCLUSIONS: These findings suggest that chronic arthritis caused by ECSA CHIKV infection has had a moderate impact in the Americas. Key Points • Chikungunya infection is responsible for moderate arthritis disease severity. • The East Central South African (ECSA) strain of CHIKV is a cause of persistent arthritis in Roraima, Brazil.

Feira de saúde do curso de medicina da UFRR: uma aproximação com a comunidade / Health fairs held by the UFRR school of medicine: an approach to the community

As Feiras de Saúde do curso de Medicina da Universidade Federal de Roraima (UFRR) buscam informar e sensibilizar a comunidade quanto à melhoria da qualidade de vida a partir da prevenção, orientando para a mudança de hábitos de vida e diagnosticando precocemente as doenças a fim de tratá-las e curá-las. Além disso, a UFRR busca se aproximar da população boa-vistense por meio desse trabalho de extensão universitária e da realização de um serviço de utilidade pública de grande relevância acadêmica e comunitária. A diversidade das lições aprendidas, registradas como relatos de experiências ou como estudos, pelo conjunto de profissionais, gestores, pesquisadores e acadêmicos constituiu um importante estímulo ao debate acerca dos limites e possibilidades do Programa Saúde da Família e da interação do acadêmico na comunidade.

Health fairs held by the School of Medicine at the Federal University in Roraima (UFRR) aim to raise community awareness concerning improved quality of life based on prevention, orienting people for lifestyle changes and early diagnosis of diseases. The university also promotes greater exchange with the population of Boa Vista through this extension work, a highly relevant public utility service for academia and the local community. The range of lessons learned, documented through reports of experiences and case studies by health professionals, administrators, researchers, and students, provided an important stimulus for the debate on the limits and possibilities of the Family Health Program and interaction between medical students and the community.

Seasonal dynamics of Aedes aegypti (Diptera: Culicidae) in the northernmost state of Brazil: a likely port-of-entry for dengue virus 4.

Roraima is the northernmost state of Brazil, bordering both Venezuela and Guyana. Appropriate climate and vector conditions for dengue transmission together with its proximity to countries where all four dengue serotypes circulate make this state, particularly the capital Boa Vista, strategically important for dengue surveillance in Brazil. Nonetheless, few studies have addressed the population dynamics of Aedes aegypti in Boa Vista. In this study, we report temporal and spatial variations in Ae. aegypti population density using ovitraps in two highly populated neighbourhoods; Centro and Tancredo Neves. In three out of six surveys, Ae. aegypti was present in more than 80% of the sites visited. High presence levels of this mosquito suggest ubiquitous human exposure to the vector, at least during part of the year. The highest infestation rates occurred during the peak of the rainy seasons, but a large presence was also observed during the early dry season (although with more variation among years). Spatial distribution of positive houses changed from a sparse and local pattern to a very dense pattern during the dry-wet season transition. These results suggest that the risk of dengue transmission and the potential for the new serotype invasions are high for most of the year.

Seasonal dynamics of Aedes aegypti (Diptera: Culicidae) in the northernmost state of Brazil: a likely port-of-entry for dengue virus 4

Roraima is the northernmost state of Brazil, bordering both Venezuela and Guyana. Appropriate climate and vector conditions for dengue transmission together with its proximity to countries where all four dengue serotypes circulate make this state, particularly the capital Boa Vista, strategically important for dengue surveillance in Brazil. Nonetheless, few studies have addressed the population dynamics of Aedes aegypti in Boa Vista. In this study, we report temporal and spatial variations in Ae. aegypti population density using ovitraps in two highly populated neighbourhoods; Centro and Tancredo Neves. In three out of six surveys, Ae. aegypti was present in more than 80 percent of the sites visited. High presence levels of this mosquito suggest ubiquitous human exposure to the vector, at least during part of the year. The highest infestation rates occurred during the peak of the rainy seasons, but a large presence was also observed during the early dry season (although with more variation among years). Spatial distribution of positive houses changed from a sparse and local pattern to a very dense pattern during the dry-wet season transition. These results suggest that the risk of dengue transmission and the potential for the new serotype invasions are high for most of the year.