RESUMO
Viral metagenomics of feces collected from 58 Peruvian children with unexplained diarrhea revealed several small circular ssDNA genomes. Two genomes related to sequences previously reported in feces from chimpanzees and other mammals and recently named smacoviruses were characterized and then detected by PCR in 1.7 % (1/58) and 19 % (11/58) of diarrheal samples, respectively. Another three genomes from a distinct small circular ssDNA viral group provisionally called pecoviruses encoded Cap and Rep proteins with <35 % identity to those in related genomes reported in human, seal, porcine and dromedary feces. Pecovirus DNA was detected in 15.5 % (9/58), 5.9 % (3/51) and 3 % (3/100) of fecal samples from unexplained diarrhea in Peru, Nicaragua and Chile, respectively. Feces containing these ssDNA genomes also contained known human enteric viral pathogens. The cellular origins of these circular ssDNA viruses, whether human cells, ingested plants, animals or fungal foods, or residents of the gut microbiome, are currently unknown.
Assuntos
DNA Circular/genética , DNA Viral/genética , Diarreia/virologia , Viroses/virologia , Chile/epidemiologia , Diarreia/epidemiologia , Fezes/virologia , Genoma Viral , Humanos , Nicarágua/epidemiologia , Peru/epidemiologia , Filogenia , Viroses/epidemiologiaRESUMO
Viruses with small circular ssDNA genomes encoding a replication initiator protein can infect a wide range of eukaryotic organisms ranging from mammals to fungi. The genomes of two such viruses, a cyclovirus (CyCV-SL) and gemycircularvirus (GemyCV-SL) were detected by deep sequencing of the cerebrospinal fluids of Sri Lankan patients with unexplained encephalitis. One and three out of 201 CSF samples (1.5%) from unexplained encephalitis patients tested by PCR were CyCV-SL and GemyCV-SL DNA positive respectively. Nucleotide similarity searches of pre-existing metagenomics datasets revealed closely related genomes in feces from unexplained cases of diarrhea from Nicaragua and Brazil and in untreated sewage from Nepal. Whether the tropism of the cyclovirus and gemycircularvirus reported here include humans or other cellular sources in or on the human body remains to be determined.
Assuntos
Circoviridae/isolamento & purificação , DNA Circular/genética , DNA de Cadeia Simples/genética , Diarreia/virologia , Encefalite/virologia , Genoma Viral , Esgotos/virologia , Adolescente , Adulto , Idoso , Brasil , Líquido Cefalorraquidiano/virologia , Criança , Pré-Escolar , Circoviridae/genética , Análise por Conglomerados , DNA Circular/isolamento & purificação , DNA de Cadeia Simples/isolamento & purificação , Fezes/virologia , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Nicarágua , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Homologia de Sequência , Sri Lanka , Adulto JovemRESUMO
Some respiratory tract infections remain unexplained despite extensive testing for common pathogens. Nasopharyngeal aspirates (NPAs) from 120 Chilean infants from Santiago with acute lower respiratory tract infections were analysed by viral metagenomics, revealing the presence of nucleic acids from anelloviruses, adenovirus-associated virus and 12 known respiratory viral pathogens. A single sequence read showed translated protein similarity to cycloviruses. We used inverse PCR to amplify the complete circular ssDNA genome of a novel cyclovirus we named CyCV-ChileNPA1. Closely related variants were detected using PCR in the NPAs of three other affected children that also contained anelloviruses. This report increases the current knowledge of the genetic diversity of cycloviruses whose detection in multiple NPAs may reflect a tropism for human respiratory tissues.