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Molecular characterization of avian malaria hemoparasites in wild birds
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Abstract(s)
A malária aviária é uma doença por vezes subestimada no que diz respeito ao seu impacto e patogenicidade em aves selvagens. Os estudos epidemiológicos e de caracterização molecular de hemoparasitas em aves selvagens, permitem avaliar a sua presença nestes animais e atuar em termos de medicina da conservação. Em Portugal cerca de 150 espécies de aves são consideradas vulneráveis ou em perigo de extinção, e apesar da maioria das causas de morte não serem de origem infeciosa, é necessário realizar estudos sobre a presença de hemoparasitas, já que as consequências indiretas da sua presença na saúde de aves selvagens não são completamente conhecidas. Além disso, estes estudos são uma fonte de informação que pode ajudar centros de recuperação, onde várias espécies co-existem num espaço, mas com o objetivo de serem libertadas. O objetivo deste estudo é avaliar a presença de Plasmodium, Haemoproteus e Leucocytozoon em aves selvagens, que deram entrada num centro de recuperação da zona centro de Portugal. Para o efeito foram recolhidas amostras de tecido hepático e esplénico, maioritariamente através de necrópsia, para posterior extração de DNA e testagem através de nested-PCR a presença dos géneros referidos. Num grupo de 70 amostras de animais diferentes, 17 (24,3%) amostras foram positivas para Plasmodium/Haemoproteus e 30 (42,9%) para Leucocytozoon, sendo que 15 (21,4%) foram infeções mistas. Por conveniência, dando foco a espécies em perigo, algumas amostras foram sequenciadas e organizadas em árvores filogenéticas, observando-se várias linhagens de Leucocytozoon sp. com diferentes características em termos dos hospedeiros que afetam. Também foram sequenciadas amostras com Plasmodium matutinum e Plasmodium relictum que apresentaram diferentes grupos de infeção em diferentes espécies. Algumas das amostras testadas foram os primeiros casos reportados nas espécies Aquila pennata (Águia-calçada), Gyps fulvus (Grifo), Motacilla alba (Álveola-branca), Neophron percnopterus (Abutre-do-egipto) e Picus viridis (Pica-pau-verde), onde se incluem duas espécies de aves necrófagas, grupo onde não estava referido a presença de malária aviária. As amostras de aves com presença de lesões hepáticas e esplénicas encontradas em necrópsia apresentaram elevada frequência de hemoparasitas. Também foi frequente a presença de hemoparasitas em aves recém-nascidas até juvenis. A análise filogenética evidenciou linhagens que afetam grupos específicos de aves e outros que afetam uma enorme variedade de ordens de aves.
Avian malaria is a disease that is sometimes underrated on its impact and pathogenicity in wild birds. Epidemiologic studies and molecular characterization of hemoparasites in wild birds, allows the evaluation of its presence in these animals and act for conservation medicine. In Portugal around 150 species of birds are considered vulnerable or in danger of extinction, and although the majority of their causes of death don’t have an infectious origin, it is necessary to control the presence of hemoparasite whose indirect consequences in the health of wild birds are not completely known. These surveys are a source of information that can help rescue centers, where multiples species co-exist in one space but with the goal of being released. The objective of this study is to evaluate the presence of Plasmodium, Haemoproteus and Leucocytozoon in wild birds, admitted in a rescue center in the center region of Portugal. For this purpose, liver and spleen samples were collected, mostly during necropsy, for DNA extraction and nested-PCR. From the 70 samples collected from different birds, 17 (24,3%) were positive for Plasmodium/Haemoproteus, 30 (42,9%) for Leucocytozoon, and 15 (21,4%) were mixed infections. Focusing on endangered species, some samples were sent for sequencing and phylogenetic studies, showing different linages of Leucocytozoon sp. with different characteristics of different hosts that can affect. Other samples were positive for Plasmodium matutinum and Plasmodium relictum that showed different infection behaviour in different species. This study provided first reports, specifically on Aquila pennata, Gyps fulvus, Motacilla alba, Neophron percnopterus e Picus viridis. That includes two species of necrophage birds, a group were avian malaria were not referred previously. Samples from birds with hepatic and splenic lesions found in necropsy presented a high frequency of hemoparasites. It was also frequent the presence of hemoparasites in nestlings. The phylogenetic analysis showed the capacity of different linages to affect very specific groups and others that affect a high variety of bird’s orders.
Avian malaria is a disease that is sometimes underrated on its impact and pathogenicity in wild birds. Epidemiologic studies and molecular characterization of hemoparasites in wild birds, allows the evaluation of its presence in these animals and act for conservation medicine. In Portugal around 150 species of birds are considered vulnerable or in danger of extinction, and although the majority of their causes of death don’t have an infectious origin, it is necessary to control the presence of hemoparasite whose indirect consequences in the health of wild birds are not completely known. These surveys are a source of information that can help rescue centers, where multiples species co-exist in one space but with the goal of being released. The objective of this study is to evaluate the presence of Plasmodium, Haemoproteus and Leucocytozoon in wild birds, admitted in a rescue center in the center region of Portugal. For this purpose, liver and spleen samples were collected, mostly during necropsy, for DNA extraction and nested-PCR. From the 70 samples collected from different birds, 17 (24,3%) were positive for Plasmodium/Haemoproteus, 30 (42,9%) for Leucocytozoon, and 15 (21,4%) were mixed infections. Focusing on endangered species, some samples were sent for sequencing and phylogenetic studies, showing different linages of Leucocytozoon sp. with different characteristics of different hosts that can affect. Other samples were positive for Plasmodium matutinum and Plasmodium relictum that showed different infection behaviour in different species. This study provided first reports, specifically on Aquila pennata, Gyps fulvus, Motacilla alba, Neophron percnopterus e Picus viridis. That includes two species of necrophage birds, a group were avian malaria were not referred previously. Samples from birds with hepatic and splenic lesions found in necropsy presented a high frequency of hemoparasites. It was also frequent the presence of hemoparasites in nestlings. The phylogenetic analysis showed the capacity of different linages to affect very specific groups and others that affect a high variety of bird’s orders.
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Keywords
Avian malaria Plasmodium Haemoproteus Leucocytozoon Gyps fulvus Neophron percnopterus