RESUMO
BACKGROUND: The newly described human bocavirus (HBoV) species 2 and 3 have been repeatedly detected in stool strengthening the possibility that these viruses might present a tropism for the gastrointestinal tract and may be etiological agents of diarrhea. OBJECTIVE: In this study we assessed the presence of HBoV2 and HBoV3 in stool specimens from Brazilians with acute gastroenteritis. STUDY DESIGN: Stool samples from Brazilian patients with acute diarrhea were analyzed for HBoV2 and HBoV3 by PCR assay. Full or partial genome sequences were obtained for selected isolates. Electron microscopy analysis was used to investigate virus morphology. RESULTS: Electron microscopy confirmed the presence of virus-like particles in HBoV PCR-positive specimens, with morphology similar to other members of the Parvoviridae family. Five samples out of 807 (0.6%) were positive for HBoV3. Three of the HBoV3-positive patients were HIV/AIDS positive. A selected group of 144 samples was also tested for HBoV2 and 30 samples (20.8%) were positive, 11 of which were HIV/AIDS positive. CONCLUSION: This study reports the detection and genetic characterization of HBoV3 and HBoV2 in the stool of Brazilian patients with acute diarrhea. This is the first description of HBoV3 outside Australia, suggesting a wide global distribution of this virus. Further studies are needed to better understand the role of HBoV in gastrointestinal infections, particularly among patients with HIV/AIDS.
Assuntos
Fezes/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Bocavirus Humano/classificação , Bocavirus Humano/isolamento & purificação , Infecções por Parvoviridae/epidemiologia , Infecções por Parvoviridae/virologia , Brasil/epidemiologia , Criança , Análise por Conglomerados , DNA Viral/química , DNA Viral/genética , DNA Viral/isolamento & purificação , Humanos , Lactente , Masculino , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Homologia de Sequência , Vírion/ultraestruturaRESUMO
The role of group C rotaviruses as a cause of diarrhea was examined among children <17 years of age admitted to a Hospital in a suburban area of Buenos Aires, Argentina between 1997 and 2003. A total of 1,579 fecal samples were screened for group A (RVA) and C (RVC) rotaviruses by two in-house ELISA methods at Quilmes University (UNQ-ELISA). Samples positive, doubtful and negative by RVC specific UNQ-ELISA (n = 246) were examined further for RVC by another in-house ELISA (CDC-ELISA), electron microscopy, RT-PCR, nested PCR, and Southern hybridization. Sensitivity, specificity, and predictive values for each test were determined. While the sensitivity was comparable for the nested PCR and CDC-ELISA methods (82.5%), the molecular methods were slightly more specific. Poorly preserved particles were often seen in fecal samples, suggesting that degradation of RNA could be a factor influencing the performance of molecular methods. The incidence of RVC was estimated to be 3% without apparent differences among seasons. RVC infected patients had a significantly (P < 0.001) higher median age (6 years vs. 1 year) than those with RVA infection. Sequence of the RVC VP7 gene from six Argentinean strains and sequences reported previously in different countries showed high nucleotide (94.4-99.9%) sequence identities, indicating a high degree of conservation for human RVC VP7 genes among strains collected on five continents over a period of 17 years. These findings indicate that RVC is a significant cause of diarrhea and it is necessary to develop simple and sensitive serological methods for its detection.