Prevalence and molecular characterization of parechovirus A in children with acute gastroenteritis in Shenzhen, 2016–2018

Parechovirus A (PeV-A), which causes a wide variety of diseases, is prevalent among young children. However, little is currently known about PeV-A infections in children with acute gastroenteritis in mainland China. In this study, we investigated the molecular epidemiology of acute gastroenteritis in Shenzhen, southern China, with an emphasis on PeV-A infections. A total of 1220 stool specimens from 1220 outpatient children under 5 years old with acute gastroenteritis were collected from January 2016 to December 2018. Viral RNA was detected by a real-time RT-PCR and PCR method. The PeV-A isolates were genotyped by sequencing the VP3/VP1 region. Of 1220 specimens, 148 (12.1%) were positive for PeV-A. The predominant genotype was PeV-A 1B (68.9%), followed by PeV-A 4 (12.2%), PeV-A 14 (6.1%), PeV-A 1A (5.4%), PeV-A 6 (2.7%), PeV-A 3 (2.7%) and PeV-A 5 (2.0%). It was found that 68.2% of PeV-A infections occurred in the summer and rainy months (June to September) in southern China. The majority of PeV-A-positive patients (97.3%) were younger than 24 months old. PeV-A coinfection with norovirus, rotavirus, astrovirus and adenovirus was found in thirty specimens (30/148, 20.3%), five specimens (5/148, 3.4%), five specimens (5/148, 3.4%), and two specimens (2/148, 1.4%), respectively. Coinfections with more than one other enteric virus were not observed in any of the PeV-A-positive specimens. Phylogenetic analysis revealed that the PeV-A isolates from Shenzhen were closely related to each other and to strains circulating in China, suggesting endemic circulation of PeV-A in China. The results of this study indicate that PeV-A is one of important pathogens of acute gastroenteritis in young children and that coinfection is a possible mode of PeV-A infection. PeV-A associated with acute gastroenteritis exhibited high genotypic diversity in Shenzhen, southern China.