Identification of a novel cosavirus species in faeces of children and its relationship with acute gastroenteritis in China

Abstract

ObjectivesTo assess the prevalence of human cosavirus (HCosV) in China and to determine the association of a novel HCosV (Cosa-CHN) with acute gastroenteritis (AGE). MethodsA case–control study with 461 paired stool samples from diarrhoea and healthy children was conducted. Real-time PCR and nested PCR were used to detect the HCosVs. Rapid amplification of cDNA ends was used to obtain the ends of the Cosa-CHN. ResultsKnown HCosVs were detected in two control samples, while Cosa-CHN was detected in eight (1.7%) and six (1.3%) of the case and control samples respectively. The complete genome of Cosa-CHN comprises 7213 bp. The P1 and P2 regions of the Cosa-CHN were closely related to those of HCosV B, while the P3 region was most similar to that of HCosV D, albeit with low amino acid identities (66 and 67% respectively). Phylogenetic analyses of the polyprotein and partial VP3/VP1 regions indicated that Cosa-CHN could be classified as a novel species (tentatively named HCosV G) in cosavirus. There was no significant difference in detection rate (p 0.59) or mean virus load (p 0.43) of Cosa-CHN between the cases and controls. Statistical analysis revealed no association between Cosa-CHN and AGE (p 0.76), and the virus did not exacerbate clinical symptoms. ConclusionsA low prevalence of HCosV was detected, but a novel Cosavirus species was found in children with and without gastroenteritis in this study. The evidence did not support a causative role for the novel virus in paediatric AGE.