Multiple enterovirus genotypes circulating in children hospitalized with acute gastroenteritis in Thailand

Highlights

• EV was detected by RT-PCR of the 5′UTR.

• EV prevalence among children with acute diarrhea was 5.8% (73/1266).

• Three EV species including A, B, and C were detected.

• This study identified 28 different EV genotypes by VP1 gene analysis.

• EV-C96 and CV-A24 were the most common genotypes.

Abstract

Enterovirus (EV) infection is widespread and can lead to a broad range of clinical symptoms, from mild to severe forms of disease. EVs are not always classified as pathogen and the epidemiological surveillance of EV infection in acute gastroenteritis cases in Thailand remains unexplored. This study aims to investigate the frequency, seasonality and molecular characteristics of EV circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand from 2010 to 2014. A total of 1266 fecal samples were included in this study. RT-PCR amplification of the 5′UTR was used for EV screening and phylogenetic analysis of the VP1 sequence was performed for EV genotyping. EV was detected in 5.8% of infections (73 out of 1266). Based on VP1 sequence analysis, over half (50.8%) of the identified EV cases were caused by species C, and the next two most frequent were species B and A (35.4% and 13.8%, respectively). This study identified 28 different EV genotypes, EV-C96 and coxsackievirus A24 were the most frequent genotype detected (12.3% each). EV was detected throughout the year with an increase of detection rate in December–January and May–June. In conclusion, this study reported the prevalence of EV infection with a wide variety of EV genotypes in children with acute diarrhea.

Introduction

Acute gastroenteritis is a major cause of morbidity and mortality among infants and young children around the world. It is the third leading cause of death in children < 5 years of age with the highest incidence occurring in developing countries where there are 2–2.5 million deaths annually worldwide (Kotloff et al., 2013, O'Ryan et al., 2005, Platts-Mills et al., 2015, Walker et al., 2013). Among the viral agents, rotavirus (RV), norovirus (NoV), astrovirus (AstV), and adenovirus (AdV) account for a significant number of cases of acute gastroenteritis (Clark and McKendrick, 2004, Monavari et al., 2017, Thongprachum et al., 2016, Zhou et al., 2017).

Enteroviruses (EVs) are small, non-enveloped, single-stranded RNA viruses which belong to the Picornaviridae family (Tapparel et al., 2013). To date, EVs are known to include 12 species, EV-A to EV-I and rhinovirus A to C. There are over one hundred EVs that can infect humans and those have been classified into 4 species, EV-A to D according to their molecular and antigenic properties. Human EV-A to D also represent a large number of serotypes among echovirus (E), coxsackievirus A (CV-A), CV-B, poliovirus (PV), and rhinovirus which are responsible for major public health concern. EVs are primarily transmitted by fecal-oral and respiratory routes. These viruses are circulating worldwide and infections are more common in summer and early autumn (Pallansch and Roos, 2007). EV infections are associated with several acute and chronic diseases with a wide range of clinical illness including those associated with gastrointestinal or respiratory tracts and the central nervous system (Abzug, 2014, Lee et al., 2013, Pallansch and Roos, 2007). EV infections are mostly asymptomatic, however, about 1.0% leads to severe disease with high morbidity and mortality in young children and infants (Abzug, 2014, Pallansch and Roos, 2007).

Although the impact of EV infection on diarrheal disease is not well documented, the diarrheic potential has been recognized and reported in a number of surveillance studies (Abe et al., 2000, Maslin et al., 2007, Patil et al., 2015, Phan et al., 2005, Rao et al., 2013, Scarcella et al., 2009, Silva et al., 2008). EV detection is often not included in pathogen surveillance of diarrhea, hence, the epidemiological study of EV infection in acute gastroenteritis patients is limited, particularly in Thailand. In this study, we reported the epidemiology and molecular characteristics of EV circulating in children hospitalized with acute gastroenteritis in Thailand during the 5 year period, from 2010 to 2014.