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Detecção e caracterização de Parvovírus em amostras fecais de primatas não humanos em cativeiro
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Os parvovírus são pequenos vírus com genoma de DNA de cadeia simples linear (~5 kb), simetria icosaédrica, sem invólucro, membros da família Parvoviridae. Os membros da subfamília Parvovirinae infectam vertebrados e causam desde infecções assintomáticas até um largo espectro de doenças agudas e crónicas. Desde 2005, os parvovírus 4 (PARV4, género Tetraparvovirus), bocavírus (BoV, género Bocaparvovirus) e bufavírus (BuV, género Protoparvovirus) foram detectados em amostras fecais humanas e num número reduzido de símios. O conhecimento sobre associação a doença, origem e evolução destes parvovírus de primatas é muito limitado.
O objectivo deste estudo consistiu em detectar e caracterizar parvovírus PARV4, BoV e BuV em amostras fecais de primatas não humanos em cativeiro no Jardim Zoológico de Lisboa. Com esse intuito, 128 amostras fecais de grandes símios, gibões, macacos do Velho Mundo, macacos do Novo Mundo e lémures foram testadas para a presença de DNA de parvovírus por PCR com primers degenerados, específicos de género, tendo como alvo um fragmento do gene NS1 de parvovírus, e sequenciados os amplicões obtidos.
Detectou-se DNA genómico de BoV em 5,5% (7/128) das amostras fecais, todas provenientes de chimpanzé-comum, enquanto a presença de DNA de BuV foi demonstrada em 14,8% (19/128). As últimas eram originárias de chimpanzé-comum (8/10), gibão-de-mãos-brancas (2/4) e macacos do Velho Mundo, nomeadamente macaco-do-japão (1/10), macaco-cauda-de-leão (5/5), macaco-de-nariz-branco (2/4) e macaco-diana (1/2). Não foi detectado DNA de vírus semelhantes a PARV4 nas amostras fecais analisadas.
As novas sequências de BoV aqui descritas, provenientes exclusivamente de chimpanzé-comum, revelaram uma grande homogeneidade genética e, baseado na análise filogenética, uma relação estreita com duas outras sequência de BoV de chimpanzé e BoV3 humano. Para além do chimpanzé-comum, o gorila é o outro hospedeiro primata não humano onde foram identificados BoV o que, conjuntamente com estes resultados, sugere que os grandes símios sejam hospedeiros naturais destes vírus. As sequências de BuV, de um modo geral, surgem nas árvores filogenéticas segregadas de acordo com o grupo taxonómico do hospedeiro de onde derivam, sendo possível observar grupos monofiléticos que incluem i) BuV humanos e de chimpanzé-comum, ii) BuV de macacos do Velho Mundo e iii) BuV de gibões. De salientar que se trata da primeira descrição da detecção de BuV para qualquer uma das espécies acima mencionadas. É também de realçar que é a primeira vez que os parvovírus são identificados em primatas da família Hylobatidae e, considerando o seu posicionamento na árvore filogenética e distanciamento dos outros bufavírus, é possível que no futuro estes vírus venham a constituir uma nova espécie viral dentro do género Protoparvovirus. A sequenciação do genoma completo dos novos parvovírus descritos será fundamental para elucidar a sua origem e evolução, nomeadamente a ocorrência de potenciais eventos de recombinação. Conseguiu-se ainda demonstrar a replicação de BuV de chimpanzé numa linha celular humana, facto que permitirá estabelecer um modelo de replicação in vitro destes vírus.
Parvoviruses are small non-enveloped icosahedral viruses with a linear single-stranded DNA genome (~5kb) in the Parvoviridae family. Members of the Parvovirinae subfamily infect vertebrates and cause from asymptomatic infections to a large spectrum of acute and chronic diseases. Since 2005, parvovirus 4 (PARV4, Tetraparvovirus genus), bocavirus (BoV, Bocaparvovirus genus), and bufavirus (BuV, Protoparvovirus genus) were identified in fecal samples from humans and a small number of nonhuman primates. Correlates of disease, origin and evolution of these primate parvoviruses are limited. The objective of this study was to detect and to characterize parvoviruses PARV4, BoV, and BuV in fecal samples of nonhuman primates in captivity in the Lisbon’s Zoo. With this aim, 128 fecal samples from great apes, gibbons, Old World monkeys, New World monkeys, and lemurs were screened for the presence of parvovirus DNA by PCR using genus-specific, degenerated primers targeting part of the NS1 gene and the amplicons sequenced for analysis. BoV DNA was detected in 5.5% (7/128) of the fecal samples, all obtained from chimpanzees, while BuV DNA sequences were demonstrated in 14.8% (19/128). The latter were collected from chimpanzees (8/10), white-handed gibbons (2/4), and Old World monkeys, namely Japanese macaque (1/10), lion-tailed macaque (5/5), red-tailed monkey (2/4), and Diana monkey (1/2). Genomic DNA from PARV4-like viruses was not identified in the analyzed fecal samples. The new chimpanzee BoV nucleotide sequences described herein demonstrated high genetic homogeneity and, based on phylogenetic analysis, showed a close relationship to two other chimpanzee BoV and human BoV3. Besides the chimpanzees, the gorilla is the other nonhuman primate host where BoV was identified which, together with these results, suggests that great apes are natural hosts of these viruses.Generally, the BuV sequences segregated in phylogenetic trees according to the host taxonomic group they were derived from, being possible to observe monophyletic groups consisting on i) chimpanzee and human BuV, ii) Old World monkey BuV, and iii) gibbon BuV. It is noteworthy that this is the first description of BuV detection for any of the aforementioned simian species. It should also be noted that it is the first time that parvoviruses are identified in primates from the Hylobatidae family and, considering their position in the phylogenetic tree and distance from other bufaviruses, it is possible that in the future these viruses might originate a new viral species within the Protoparvovirus genus. Full-length genome sequencing is required to clarify the origin and evolution of the parvoviruses identified, particularly the occurrence of recombination events. It has also been demonstrated the replication of chimpanzee BuV in a human cell line, making feasible the establishment of an in vitro replication model of these viruses.
Parvoviruses are small non-enveloped icosahedral viruses with a linear single-stranded DNA genome (~5kb) in the Parvoviridae family. Members of the Parvovirinae subfamily infect vertebrates and cause from asymptomatic infections to a large spectrum of acute and chronic diseases. Since 2005, parvovirus 4 (PARV4, Tetraparvovirus genus), bocavirus (BoV, Bocaparvovirus genus), and bufavirus (BuV, Protoparvovirus genus) were identified in fecal samples from humans and a small number of nonhuman primates. Correlates of disease, origin and evolution of these primate parvoviruses are limited. The objective of this study was to detect and to characterize parvoviruses PARV4, BoV, and BuV in fecal samples of nonhuman primates in captivity in the Lisbon’s Zoo. With this aim, 128 fecal samples from great apes, gibbons, Old World monkeys, New World monkeys, and lemurs were screened for the presence of parvovirus DNA by PCR using genus-specific, degenerated primers targeting part of the NS1 gene and the amplicons sequenced for analysis. BoV DNA was detected in 5.5% (7/128) of the fecal samples, all obtained from chimpanzees, while BuV DNA sequences were demonstrated in 14.8% (19/128). The latter were collected from chimpanzees (8/10), white-handed gibbons (2/4), and Old World monkeys, namely Japanese macaque (1/10), lion-tailed macaque (5/5), red-tailed monkey (2/4), and Diana monkey (1/2). Genomic DNA from PARV4-like viruses was not identified in the analyzed fecal samples. The new chimpanzee BoV nucleotide sequences described herein demonstrated high genetic homogeneity and, based on phylogenetic analysis, showed a close relationship to two other chimpanzee BoV and human BoV3. Besides the chimpanzees, the gorilla is the other nonhuman primate host where BoV was identified which, together with these results, suggests that great apes are natural hosts of these viruses.Generally, the BuV sequences segregated in phylogenetic trees according to the host taxonomic group they were derived from, being possible to observe monophyletic groups consisting on i) chimpanzee and human BuV, ii) Old World monkey BuV, and iii) gibbon BuV. It is noteworthy that this is the first description of BuV detection for any of the aforementioned simian species. It should also be noted that it is the first time that parvoviruses are identified in primates from the Hylobatidae family and, considering their position in the phylogenetic tree and distance from other bufaviruses, it is possible that in the future these viruses might originate a new viral species within the Protoparvovirus genus. Full-length genome sequencing is required to clarify the origin and evolution of the parvoviruses identified, particularly the occurrence of recombination events. It has also been demonstrated the replication of chimpanzee BuV in a human cell line, making feasible the establishment of an in vitro replication model of these viruses.
Descrição
Palavras-chave
Primatas não humanos Parvovírus PARV4 Bocavírus Ciências biomédicas Biologia molecular
Contexto Educativo
Citação
Editora
Instituto de Higiene e Medicina Tropical