Evolutionary analysis of human parechovirus type 3 and clinical outcomes of infection during the 2017\u201318 Australian epidemic

Anthony Chamings,Soren Alexandersen,Yano Yoga,Kristine K Macartney,Philip N Britton,Leon Caly,Julian Druce

doi:10.1038/s41598-019-45445-z

Abstract

Human parechovirus type 3 (HPeV3) can cause severe sepsis-like illness in young infants and may be associated with long term neurodevelopmental delay later in childhood. We investigated the molecular epidemiology of HPeV infection in thirty three infants requiring hospitalization before, during and after the peak of the 2017/18 HPeV epidemic wave in Australia. During the peak of the epidemic, all cases were infected with an HPeV3, while before and after the peak, HPeV1 was the predominant type detected. The predominant HPeV3 was the recombinant HPeV3 also detected in the 2013/14 and 2015/16 Australian epidemics. Sepsis-like or meningitis-like symptoms were only reported in cases infected with the recombinant HPeV3. Phylogenetic analysis of the recombinant HPeV3 revealed that the virus continued to evolve, also between the Australian outbreaks, thus indicating continued circulation, despite not being detected and reported in Australia or elsewhere in between epidemic waves. The recombinant HPeV3 continued to show a remarkable stability in its capsid amino acid sequence, further strengthening our previous argument for development of a vaccine or immunotherapeutics to reduce the severity of HPeV3 outbreaks due to this virus.

Highlights

Human parechovirus (HPeV) is a small non-enveloped RNA virus in the virus family Picornaviridae
Of the 33 clinical cases included in this study, 26 cases were infected with an Human parechovirus type 3 (HPeV3), and 7 cases were infected with an HPeV type 1 (HPeV1) (Table 1: case and sample identifiers)
In 24 of the 26 HPeV3 infected infants, the virus detected was closely related to the Australian recombinant HPeV3 identified as the predominant virus in the previous two epidemics in Australia in 2013 and 2015

Summary

Introduction

Human parechovirus (HPeV) is a small non-enveloped RNA virus in the virus family Picornaviridae. In particular human parechovirus type 3 (HPeV3), are capable of causing severe disease including central nervous system (CNS) infection and a sepsis-like syndrome in very young children (aged < 3 months)[2,3,4]. The earliest published HPeV3 positive sample in Australia was collected from a sick infant in 201220 This 2012 virus was most similar to an HPeV3 identified in an outbreak in children and adults with myalgia in Yamagata, Japan in 201121. The objective of this study was to genetically characterize the human parechoviruses involved in the outbreak in south-east Australia in 2017–18, and determine if an association existed between the genotype of the virus and the severity of disease observed in infected infants

Objectives

Methods

Results

Conclusion