Molecular epidemiology of parechovirus, Aichi virus and salivirus in gastroenteritis in Hong Kong

Abstract

Gastroenteritis in the form of diarrhea and vomiting is common in human and is mostly caused by viral infection. As the significant proportion of gastrointestinal infections are still not diagnosed, novel viruses are suggested to be the causative agents of unknown gastroenteritis. Novel and emerging picornaviruses, including human parechovirus (HPeV), Aichi virus (AiV) and salivirus (SalV) are suggested to play an important role in acute gastroenteritis. Since little was known about the molecular and clinical epidemiology of these viruses, the present study aims to investigate the presence of HPeV, AiV and SalV in fecal samples of children with acute gastroenteritis in Hong Kong.

Retrospective and prospective studies were performed using fecal samples from pediatric patients hospitalized for acute gastroenteritis from November 2004 to August 2005, August 2006 to October 2006 and September 2012 to August 2013. Among 1708 fecal samples subjected to RT-PCR using primers targeted to 5’NCR of picornaviruses, viruses were detected in 57 samples, with 47 patients (2.8%) positive for HPeVs, three patients (0.18%) positive for AiV and one patient (0.1%) positive for SalV. Phylogenetic analysis of the partial VP1 capsid gene of the 33 HPeV strains revealed the presence of genotypes of HPeV- 1, 3, 4, 5, 7, 10, among which HPeV1 was the predominant genotype circulating in our population. The peak activity of HPeV infection was in autumn. Of the three children with AiV detected in fecal samples, phylogenetic analysis of the partial VP1 and 3CD regions indicated the three AiV strains from fecal samples belonged to the AiV genotype A. Co-detection of different pathogens was noted in 6 samples (10.5%) of 57 stool samples positive for picornaviruses. Among the five samples with HPeV, co-detection with HBoV, AiV, SalV and Aeromonas were observed. In one sample with AiV, picobirnavirus was identified. In conclusion, HPeV, AiV and SalV were found to be present in fecal samples of Hong Kong children with gastroenteritis, with HPeV being the most common virus detected. Routine screening for these viruses in young children with gastroenteritis may better define their epidemiology and help prevent their transmission.