Molecular Analysis Reveals a High Diversity of Anopheline Mosquitoes in Yanomami Lands and the Pantanal Region of Brazil.

Identifying the species of the subfamily Anophelinae that are Plasmodium vectors is important to vector and malaria control. Despite the increase in cases, vector mosquitoes remain poorly known in Brazilian indigenous communities. This study explores Anophelinae mosquito diversity in the following areas: (1) a Yanomami reserve in the northwestern Amazon Brazil biome and (2) the Pantanal biome in southwestern Brazil. This is carried out by analyzing cytochrome c oxidase (COI) gene data using Refined Single Linkage (RESL), Assemble Species by Automatic Partitioning (ASAP), and tree-based multi-rate Poisson tree processes (mPTP) as species delimitation approaches. A total of 216 specimens collected from the Yanomami and Pantanal regions were sequenced and combined with 547 reference sequences for species delimitation analyses. The mPTP analysis for all sequences resulted in the delimitation of 45 species groups, while the ASAP analysis provided the partition of 48 groups. RESL analysis resulted in 63 operational taxonomic units (OTUs). This study expands our scant knowledge of anopheline species in the Yanomami and Pantanal regions. At least 18 species of Anophelinae mosquitoes were found in these study areas. Additional studies are now required to determine the species that transmit Plasmodium spp. in these regions.

Environmental variables associated with anopheline larvae distribution and abundance in Yanomami villages within unaltered areas of the Brazilian Amazon.

BACKGROUND: Many indigenous villages in the Amazon basin still suffer from a high malaria burden. Despite this health situation, there are few studies on the bionomics of anopheline larvae in such areas. This publication aims to identify the main larval habitats of the most abundant anopheline species and to assess their associations with some environmental factors. METHODS: We conducted a 19-month longitudinal study from January 2013 to July 2014, sampling anopheline larvae in two indigenous Yanomami communities, comprised of four villages each. All natural larval habitats were surveyed every two months with a 350 ml manual dipper, following a standardized larval sampling methodology. In a third study area, we conducted two field expeditions in 2013 followed by four systematic collections during the long dry season of 2014-2015. RESULTS: We identified 177 larval habitats in the three study areas, from which 9122 larvae belonging to 13 species were collected. Although species abundance differed between villages, An. oswaldoi (s.l.) was overall the most abundant species. Anopheles darlingi, An. oswaldoi (s.l.), An. triannulatus (s.s.) and An. mattogrossensis were primarily found in larval habitats that were partially or mostly sun-exposed. In contrast, An. costai-like and An. guarao-like mosquitoes were found in more shaded aquatic habitats. Anopheles darlingi was significantly associated with proximity to human habitations and larval habitats associated with river flood pulses and clear water. CONCLUSIONS: This study of anopheline larvae in the Brazilian Yanomami area detected high heterogeneities at micro-scale levels regarding species occurrence and densities. Sun exposure was a major modulator of anopheline occurrence, particularly for An. darlingi. Lakes associated with the rivers, and particularly oxbow lakes, were the main larval habitats for An. darlingi and other secondary malaria vectors. The results of this study will serve as a basis to plan larval source management activities in remote indigenous communities of the Amazon, particularly for those located within low-order river-floodplain systems.

New classification of natural breeding habitats for Neotropical anophelines in the Yanomami Indian Reserve, Amazon Region, Brazil and a new larval sampling methodology.

Here we present the first in a series of articles about the ecology of immature stages of anophelines in the Brazilian Yanomami area. We propose a new larval habitat classification and a new larval sampling methodology. We also report some preliminary results illustrating the applicability of the methodology based on data collected in the Brazilian Amazon rainforest in a longitudinal study of two remote Yanomami communities, Parafuri and Toototobi. In these areas, we mapped and classified 112 natural breeding habitats located in low-order river systems based on their association with river flood pulses, seasonality and exposure to sun. Our classification rendered seven types of larval habitats: lakes associated with the river, which are subdivided into oxbow lakes and nonoxbow lakes, flooded areas associated with the river, flooded areas not associated with the river, rainfall pools, small forest streams, medium forest streams and rivers. The methodology for larval sampling was based on the accurate quantification of the effective breeding area, taking into account the area of the perimeter and subtypes of microenvironments present per larval habitat type using a laser range finder and a small portable inflatable boat. The new classification and new sampling methodology proposed herein may be useful in vector control programs.

New classification of natural breeding habitats for Neotropical anophelines in the Yanomami Indian Reserve, Amazon Region, Brazil and a new larval sampling methodology

Here we present the first in a series of articles about the ecology of immature stages of anophelines in the Brazilian Yanomami area. We propose a new larval habitat classification and a new larval sampling methodology. We also report some preliminary results illustrating the applicability of the methodology based on data collected in the Brazilian Amazon rainforest in a longitudinal study of two remote Yanomami communities, Parafuri and Toototobi. In these areas, we mapped and classified 112 natural breeding habitats located in low-order river systems based on their association with river flood pulses, seasonality and exposure to sun. Our classification rendered seven types of larval habitats: lakes associated with the river, which are subdivided into oxbow lakes and nonoxbow lakes, flooded areas associated with the river, flooded areas not associated with the river, rainfall pools, small forest streams, medium forest streams and rivers. The methodology for larval sampling was based on the accurate quantification of the effective breeding area, taking into account the area of the perimeter and subtypes of microenvironments present per larval habitat type using a laser range finder and a small portable inflatable boat. The new classification and new sampling methodology proposed herein may be useful in vector control programs.

Aspectos ecológicos da transmissão da Malária em área indígena Yanomami, Brasil / Ecological aspects of malaria transmission in Yanomami indian area, Brazil

A malária se constitui numa das principais endemias em populações indígenas na Amazônia. Porém, fatores modeladores da dinâmica da transmissão são ainda pouco entendidos, tais como os determinantes da sua heterogeneidade espacial e da ocorrência de surtos sazonais de elevadas taxas de morbimortalidade. Neste estudo, buscamos determinar a fauna, aspectos ecológicos e taxa de infecção plasmodial de anofelinos em três áreas indígenas Yanomami (Parafuri, Toototobi e Marari). Considerando as trêsáreas, as espécies mais abundantes foram An. oswaldoi s.l. e An. darlingi, quejuntas corresponderam a 59,5 por cento dos 6.333 anofelinos adultos capturados. NoToototobi, as espécies mais frequentes foram An. oswaldoi s.l. (47,3 por cento) e An.intermedius (31,8 por cento), em Parafuri foram An. oswaldoi s.l. (48,7 por cento) e An. darlingi(42,5 por cento) e, em Marari An. nuneztovari s.l. (54,9 por cento) e An. darlingi (21,6 por cento). [...] Foram processados 2.014 e 461 anofelinos para a detecção de esporozoítos dentre os coletados nos Polo Base Marari e Toototobi,respectivamente. Sete An. darlingi foram positivos para P. vivax, com taxas deinfecção de 1,63 por cento, 1,52 por cento e 2,02 por cento nas comunidades de Alapusi, Gasolina e Taibrapa, respectivamente. As taxas de inoculação entomológica correspondentes nestas comunidades foram de 65,4, 58,6 e 48,3 picadas infetantes por pessoa por ano no peridomicílio. Identificamos 160 criadouros,sendo 54 em Toototobi, 53 em Parafuri e 53 em Marari e propusemos umanova classificação de criadouros naturais em oito tipos, baseada principalmente na associação com os pulsos de inundação, sazonalidade e grau de exposição ao sol...

Malaria is a major endemic disease in indigenous populations in theAmazon. However, modulating factors of the transmission dynamics are poorlyunderstood, such as the determinants influencing its spatial hetereogeneity andthe occurrence of seasonal outbreaks associated with high rates of morbidityand mortality. In the present study, we intend to determine the faunalcomposition, ecological aspects and infection rates of the anophelines occurringin three Yanomami areas (Parafuri, Toototobi and Marari) of Brazil. Wecollected a total of 6,333 adult anophelines and the most abundant species,considering the three areas, were An. oswaldoi s.l. and An. darlingi, whichtogether accounted for 59.5 percent of the total collected. In Toototobi, the mostfrequent species were An. oswaldoi s.l. (47.3 percent) and An. intermedius (31.8 percent), inParafuri were An. oswaldoi s.l. (48.7 percent) and An. darlingi (42.5 percent) and in Marariwere An. nuneztovari s.l. (54.9 percent) and An. darlingi (21.6 percent). [...] A total of 2,014 anophelines from Marari were processed for sporozoites detectionand 461 from Toototobi. We found 7 An. darlingi infected with P. vivax in Marari,with infectivity rates of 1.63 percent, 1.52 percent and 2.02 percent in Alapusi, Gasolina andTaibrapa communities respectively. Based in the peridomiciliary collections, theEntomological Inoculation Rates (EIR) calculated for these communities were65.4, 58.6 and 48.3 infective bites per person per year respectively. Weidentified 160 breeding sites; 54 in Toototobi, 53 in Parafuri and 53 in Marariand we proposed a new larval habitat nomenclature divided in 8 types, basedmainly in the association with river flood pulses, seasonality and degree of sunexposure...

Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae) bionomics and malaria epidemiology.

Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas). Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.

Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae) bionomics and malaria epidemiology / Impacto de hidrelétricas e campos de irrigação na bionomia dos anofelinos (Diptera:Culicidae) e na epidemiologia da malária

Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas). Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.

Intervenções humanas como projetos de irrigação e usinas hidrelétricas, tem se transformado em graves problemas de saúde em muitos países, especialmente naqueles localizados nos trópicos. No presente artigo discutimos os efeitos que essas intervenções causam a dinâmica populacional dos anofelinos e nos padrões de transmissão de malaria. Foram revisados estudos feitos nas três principais regiões geográficas dos trópicos e sub-trópicos (África, Ásia e o Pacífico e Américas). Constatamos que os padrões da transmissão da malária antes da introdução dos empreendimentos, as medidas de controle, os movimentos demográficos, os padrões comportamentais das comunidades humanas e a bionomia dos anofelinos locais determinarão se o estabelecimento de campos de irrigação e/ou usinas hidrelétricas podem influenciar negativamente na saúde das pessoas. São apresentados exemplos de medidas de controle bem sucedidas nesses cenários. A utilização de Sistemas de Informação Geográfico tem sido destacada como uma importante ferramenta para subsidiar o estudo e controle da malária em áreas sob impacto ambiental.