Heterogeneidade genética de Anopheles darlingi e suas implicações para epidemiologia da malária
Arquivos
Data
2016-05-13
Autores
Lima, Melina Aulino Campos [UNESP]
Título da Revista
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Degradação florestal, alterações ambientais antropogênicas e mudanças climáticas são fatores que podem modificar a dinâmica populacional de anofelinos. Anopheles (Nyssorhynchus) dar- lingi é o principal vetor de malária no Brasil e em outros países na América do Sul. Estudos observaram o aumento da abundância do vetor An. darlingi e número de casos de malária após desflorestação e demais modificações ambientais antropogênicas. Além de ter ampla distribuição geográfica, essa espécie possui plasticidade comportamental e diversidade morfo- lógica, biológica e genética. Tendo em vista essa heterogeneidade, o presente estudo avaliou a diversidade genética populacional em An. darlingi ligada a distribuição geográfica, dinâmica sazonal e comportamento hematofágico, através de marcadores microssatélites e SNPs. Espé- cimes de An. darlingi foram coletados em dois assentamentos rurais próximos e, em uma área urbana à aproximadamente 600 km de distância. Além disso, as coletas foram realizadas no primeiro e segundo semestre e, dentro e fora das casas, durante o período de atividade hema- tofágica do vetor, ou seja, das 18-6 horas. Os resultados apresentaram subpopulações de An. darlingi em aspecto geográfico, em escalas macro e microgeográficas, acessadas com mais pro- fundidade com os dados dos SNPs. Além disso, o estudo corroborou o prévio achado de duas subpopulações de An. darlingi relacionadas ao regime de chuvas. Por fim, pela primeira vez, a heterogeneidade genética em populações simpátricas desse vetor foi encontrada e relacionada com o fenótipo de comportamento hematofágico, endo e exofagia. Esses achados demonstram a importância do entendimento e vigilância entomológica, pois possuem potencial impacto na transmissão de malária. Dado que cada localidade possui características ambientais peculia- res e portanto, diferentes composições populacionais dos vetores, intervenções específicas em menor escala passam a ser abordagens interessantes no controle da malária.
Forest degradation, human environmental alteration and climate changes are all influence anopheline populations. Anopheles darlingi is the main vector of malaria parasite in Brazil and other countries of South America. Deforestation and others anthropogenic activities have been accompanied by sharp increases in both abundance of the primary malaria vector Anopheles darlingi and numbers of malaria cases. Besides it is widely distributed, this species display great behavioral plasticity and morphological, biological and genetic diversity. The aim of this study was to analyze population genetic diversity of An. darlingi related to geographical distribution, seasonal dynamics and hematophagic behavior, using microsatellites and SNPs markers. An. darlingi specimens were collected in two close rural settlements and in an urban area about 600 km away. In addition, collections were performed in both semesters of the year and, indoor and outdoor during the biting activity period of the vector, i.e., 6pm-6am. The results showed subpopulations of An. darlingi related to geographical aspect, in a macro and micro geographic scales, better accessed with SNPs dataset. Moreover, this study corroborated with a previous finding showing two subpopulations of An. darlingi related to rainfall. Finally, for the first time, genetic heterogeneity was found in sympatric populations of this vector, and it was associated with a phenotype of hematophagic behavior, endo and exophagy. These outcomes demonstrate that genetic heterogeneity may represent an important vector phenotypic variation with potentially highly significant consequences for malaria transmission. Since each site has unique environmental characteristics and therefore, different population compositions of vectors, specific interventions on a smaller scale become interesting approaches for optimal targeted malaria transmission interventions.
Forest degradation, human environmental alteration and climate changes are all influence anopheline populations. Anopheles darlingi is the main vector of malaria parasite in Brazil and other countries of South America. Deforestation and others anthropogenic activities have been accompanied by sharp increases in both abundance of the primary malaria vector Anopheles darlingi and numbers of malaria cases. Besides it is widely distributed, this species display great behavioral plasticity and morphological, biological and genetic diversity. The aim of this study was to analyze population genetic diversity of An. darlingi related to geographical distribution, seasonal dynamics and hematophagic behavior, using microsatellites and SNPs markers. An. darlingi specimens were collected in two close rural settlements and in an urban area about 600 km away. In addition, collections were performed in both semesters of the year and, indoor and outdoor during the biting activity period of the vector, i.e., 6pm-6am. The results showed subpopulations of An. darlingi related to geographical aspect, in a macro and micro geographic scales, better accessed with SNPs dataset. Moreover, this study corroborated with a previous finding showing two subpopulations of An. darlingi related to rainfall. Finally, for the first time, genetic heterogeneity was found in sympatric populations of this vector, and it was associated with a phenotype of hematophagic behavior, endo and exophagy. These outcomes demonstrate that genetic heterogeneity may represent an important vector phenotypic variation with potentially highly significant consequences for malaria transmission. Since each site has unique environmental characteristics and therefore, different population compositions of vectors, specific interventions on a smaller scale become interesting approaches for optimal targeted malaria transmission interventions.
Descrição
Palavras-chave
Anopheles darlingi, RADseq, Malária, Genética de populações, Microssatélites