Vetores de malária em duas reservas indígenas da Amazônia Brasileira

OBJECTIVE: To describe the composition, ecological and behavioral characteristics and infectivity of Anopheles species in indigenous reserves of the Amazon region. METHODS: The study was performed in villages of the Nhamundá-Mapuera and Cuminapanema indigenous reserves, in the state of Pará, Northern Brazil, in 2002. A total of three two-week collections were conducted in each reserve, with the capture of adult and immature forms. Adult Anopheles specimens were captured using a Castro sucking tube with human landing trap in indoor and outdoor environments, from 6.00 pm to 9.00 pm and from 6.00 pm to 6.00 am, and subsequently assessed to verify parity and infectivity by plasmodiums using dissection and ELISA. Water collections near the villages were surveyed using 500 ml ladles, with 20 ladlefuls for each 10 m, covering the maximum extent of 200 m of perimeter around the breeding spot. RESULTS: Adding up the collections from both reserves, a total of 8,668 females were captured. Anopheles darlingi was the most frequent species, with higher frequency around the homes. In the Mapuera reserve, blood feeding activity was concentrated between 8.00 pm and 12.00 am, while, in Cuminapanema, it remained high until 12.00 am, decreasing after this time and increasing again early in the morning. Of all the 6,350 An. darlingi females analyzed, 18 were infected with Plasmodium vivax VK247, VK210, P. falciparum and P. malariae. In addition, other 1,450 females of other species were analyzed, but none was found infected. An. nuneztovari and Chagasia bonnae were the most frequent species in the breeding spots of the Mapuera and Cuminapanema villages, respectively. Immature An. darlingi forms were not located in Mapuera and were captured in only one of the collections of the Cuminapanema reserve. CONCLUSIONS: An. darlingi populations in the two reserves showed exophilic behavior and intense nocturnal activity. The occurrence of immature forms was little frequent and larval density was low. Vector behavioral characteristics were not favorable for the usual vector control activities.OBJETIVO: Describir la composición, características ecológicas y de comportamiento e infectividad de las especies de anofelinos en reservas indígenas en la región Amazónica. MÉTODOS: El estudio fue conducido en el año de 2002 en aldeas de las reservas indígenas Nhamundá-Mapuera y Cuminapanema en el estado Pará (Norte de Brasil). Fueron realizadas tres colectas de dos semanas en cada reserva, con capturas de adultos e inmaduros. Anofelinos adultos fueron capturados con capturador de Castro por atracción humano en los ambientes intra y peridomiciliares, en el período de las 18 h a 21 h y de las 18 h a 6 h y evaluados para verificación de la paridad e infectividad para plasmodios por disección y ELISA. Las colecciones hídricas próximas a las aldeas fueron evaluadas utilizando cucharones de 500 mL, siendo 20 cucharones a cada 10 m, cubriéndose la extensión máxima de 200 m de perímetro del criadero. RESULTADOS: Fueron capturadas 8.668 hembras sumándose las colectas de las dos reservas. Anopheles darlingi fue la especie predominante, con mayor frecuencia en el peridomicilio. En la reserva Mapuera, la actividad hematofágica se concentró entre las 20 h y 24 h y en Cuminapanema, se mantuvo elevada hasta las 24 h, disminuyendo posterior a ese horario y volviendo a elevarse en el inicio de la mañana. De las 6.350 hembras de An. darlingi examinadas, 18 estaban infectadas por Plasmodium vivax VK 247, VK 210, P. falciparum y P. malariae. Otras 1.450 hembras de otras especies fueron examinadas, pero ninguna fue encontrada infectada. An. nuneztovari y Chagasia bonnae fueron las especies más frecuentes en los criaderos de las aldeas Mapuera y Cuminapanema, respectivamente. Inmaduros de An. darlingi no fueron localizados en Mapuera y fueron capturados en sólo una de las colectas de la reserva Cuminapanema. CONCLUSIONES: Las poblaciones de An. darlingi de las dos reservas presentaron comportamiento exofílico e intensa actividad nocturna. La ocurrencia de inmaduros fue poco frecuente y la densidad larvaria fue baja. Las características de comportamiento de los vectores no se mostraron favorables a las actividades usuales de control vectorial.OBJETIVO: Descrever a composição, características ecológicas e comportamentais e infectividade das espécies de anofelinos em reservas indígenas da região Amazônica. MÉTODOS: O estudo foi conduzido no ano de 2002 em aldeias das reservas indígenas Nhamundá-Mapuera e Cuminapanema no estado do Pará. Foram realizadas três coletas de duas semanas em cada reserva, com capturas de adultos e de imaturos. Anofelinos adultos foram capturados com capturador de Castro por atração humana nos ambientes intra e peridomiciliares, no período das 18h às 21h e das 18 às 06h e avaliados para verificação da paridade e infectividade para plasmódios por dissecção e ELISA. As coleções hídricas próximas às aldeias foram pesquisadas utilizando conchas de 500 ml, sendo 20 conchadas a cada 10 m, cobrindo-se a extensão máxima de 200 m de perímetro do criadouro. RESULTADOS: Foram capturadas 8.668 fêmeas somando-se as coletas das duas reservas. Anopheles darlingi foi a espécie predominante, com maior freqüência no peridomicílio. Na reserva Mapuera, a atividade hematofágica concentrou-se entre as 20h e 24h e, em Cuminapanema, manteve-se elevada até as 24h, diminuindo após esse horário e voltando a elevar-se no início da manhã. Das 6.350 fêmeas de An. darlingi examinadas, 18 estavam infectadas por Plasmodium vivax VK 247, VK 210, P. falciparum e P. malariae. Outras 1.450 fêmeas de outras espécies foram examinadas, mas nenhuma foi encontrada infectada. An. nuneztovari e Chagasia bonnae foram as espécies mais freqüentes nos criadouros das aldeias Mapuera e Cuminapanema, respectivamente. Imaturos de An. darlingi não foram localizados em Mapuera e foram capturados em apenas uma das coletas da reserva Cuminapanema. CONCLUSÕES: As populações de An. darlingi das duas reservas apresentaram comportamento exofílico e intensa atividade noturna. A ocorrência de imaturos foi pouco freqüente e a densidade larvária foi baixa. As características comportamentais dos vetores não se mostraram favoráveis às atividades usuais de controle vetorial

Studies on malaria in Serra do Navioegion, Amapa State, Brazil

This study evaluated the status of malaria transmission in Serra do Navio region where a malaria control programme had been carried out for more than 20 years, which included the provision of a daily intake of chioroquinised salt. Malaria endemicity in the study areas [target area: Serra do Navio (SNV); control areas: Colonia Agua Branca (CAB), Porto Terezinha (PT) and Arrependido (ARR)] was established based on the spleen rate and prevalence of malaria parasites among the 2-9 years age group. SNV was defined as a non-endemic area for malaria since both rates were zero, while CAB and ARR were concluded to be mesoendemic areas since the rates were between 10 and 50%, and PT was considered hypoendemic area because both rates were under 10%. Antibody prevalence measured using IFAT with asexual form antigens of Plasmodium .falciparum and Plasmodium vivax and ELISA (asexual forms of P.falciparum, sporozoites of P.falciparurn, P.vivax type 1, P.vivax type 2, P.vivax type 3 and P.malariae/P.brasilianum) was determined for individuals from each study area. These results showed a high frequency of P.falciparum antibodies in all areas. The level of haptoglobin in 100 children from all these areas demonstrated the close relationship between hypohaptoglobinaemia and malaria in the control areas. Haskin's method , a qualitative method, was applied for testing chioroquine in urine. Therefore, chioroquine levels were measured in serum and urine using the ELISA test and the results were in agreement with the reports of the intake of chioroquine salt. The distribution and potentiality of the malaria vectors in all areas was determined. Fifteen anopheline species were identified among 3053 mosquitoes collected by human biting catches in the 4 study areas. 96.4% of the total mosquitoes caught belonged to 4 species, namely, An.albitarsis, An.braziliensis, An.nuñeztovari and An.triannulatus. An.darlingi which is considered the main vector of malaria in the Amazon region of Brazil was very scarce. Using ELISA for the detection of Plasmodium spp sporozoites a positivity rate of 0.799% (23/2876) was found covering six species: 15 An. albitarsis, 4 An. nuñeztovari, and 1 of each: An. braziliensis, An. triannulatus, An. oswaldoi and An.rangeli. 9 out 23 positive mosquitoes were infected with P. raalariae ; 9 with P. vivax- variant VK 247; 3 with P. falciparum and 2 with the classical P.vivax

Association of cerebral malaria and TNF-alpha levels: a systematic review

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Código de Financiamento 001.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Health Sciences. Postgraduate Program in Pharmaceutical Sciences. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.University of Alberta. Faculty of Medicine and Dentistry. School of Dentistry. Edmonton, Canada.Federal University of Rio de Janeiro. School of Dentistry. Department of Pediatric Dentistry and Orthodontics. Rio de Janeiro, RJ, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Background: Cerebral malaria is the most severe form of infection with Plasmodium falciparum characterized by a highly inflammatory response. This systematic review aimed to investigate the association between TNF-α levels and cerebral malaria. Methods: This review followed the Preferred Reporting of Systematic Review and Meta-analyses (PRISMA) guidelines. The search was performed at PubMed, LILACS, Scopus, Web of Science, The Cochrane Library, OpenGrey and Google Scholar. We have included studies of P. falciparum-infected humans with or without cerebral malaria and TNF-α dosage level. All studies were evaluated using a risk of bias tool and the GRADE approach. Results: Our results have identified 2338 studies, and 8 articles were eligible according to this systematic review inclusion criteria. Among the eight articles, five have evaluated TNF- α plasma dosage, while two have evaluated at the blood and one at the brain (post-Morten). Among them, only five studies showed higher TNF-α levels in the cerebral malaria group compared to the severe malaria group. Methodological problems were identified regarding sample size, randomization and blindness, but no risk of bias was detected. Conclusion: Although the results suggested that that TNF-α level is associated with cerebral malaria, the evidence is inconsistent and imprecise. More observational studies evaluating the average TNF-alpha are needed

Historical shifts in Brazilian P. falciparum population structure and drug resistance alleles.

Previous work suggests that Brazilian Plasmodium falciparum has limited genetic diversity and a history of bottlenecks, multiple reintroductions due to human migration, and clonal expansions. We hypothesized that Brazilian P. falciparum would exhibit clonal structure. We examined isolates collected across two decades from Amapá, Rondônia, and Pará state (n = 190). By examining more microsatellites markers on more chromosomes than previous studies, we hoped to define the extent of low diversity, linkage disequilibrium, bottlenecks, population structure, and parasite migration within Brazil. We used retrospective genotyping of samples from the 1980s and 1990s to explore the population genetics of SP resistant dhfr and dhps alleles. We tested an existing hypothesis that the triple mutant dhfr mutations 50R/51I/108N and 51I/108N/164L developed in southern Amazon from a single origin of common or similar parasites. We found that Brazilian P. falciparum had limited genetic diversity and isolation by distance was rejected, which suggests it underwent bottlenecks followed by migration between sites. Unlike Peru, there appeared to be gene flow across the Brazilian Amazon basin. We were unable to divide parasite populations by clonal lineages and pairwise FST were common. Most parasite diversity was found within sites in the Brazilian Amazon, according to AMOVA. Our results challenge the hypothesis that triple mutant alleles arose from a single lineage in the Southern Amazon. SP resistance, at both the double and triple mutant stages, developed twice and potentially in different regions of the Brazilian Amazon. We would have required samples from before the 1980s to describe how SP resistance spread across the basin or describe the complex internal migration of Brazilian parasites after the colonization efforts of past decades. The Brazilian Amazon basin may have sufficient internal migration for drug resistance reported in any particular region to rapidly spread to other parts of basin under similar drug pressure

Temporal and geographic distribution of <i>dhfr</i> alleles in Brazil.

<p>This table, broken into three pieces for readability, describes the genotypes and haplotypes of <i>dhfr</i> seen over time at different sites in Brazil.</p

Geographic distribution of <i>dhfr</i> and <i>dhps</i> genotypes, 1980s.

<p>This figure shows the sites examined, noted with red stars, during the 1980s for <i>dhfr</i> and <i>dhps</i> genotypes. For each gene and site, there are two pie charts. The color coding for the alleles appears in the bottom of the map. Note that alleles with fewer mutations appear in the eastern portion of the country, while the 51I/108N/164L allele appears at a central and northeastern site.</p

H_e around <i>dhps</i> from multiple periods across Brazil.

<p>The figure shows variation in H_e surrounding <i>dhps</i> during the 1980s and 1990s. It appears that H_e has increased between the 1980s (n = 21) and 1990s (n = 126) for the triple mutant. The double mutant (n = 7) seems to have a similar shape as the triple mutants. The two flat, dashed lines represent two different estimates of neutral H_e in Brazil.</p

<i>dhfr</i> triple mutant H_e changes over time (50R/108N).

<p>The figure shows variation in H_e surrounding <i>dhfr</i> for parasites carrying a 51I/108N double mutant during the 1980s (n = 10) and the 1990s (n = 8). The two flat, dashed lines represent two different estimates of neutral H_e in Brazil.</p