An Emerging Human Parechovirus Type 5 Causing Sepsis-Like Illness in Infants in Australia.

Chamings Chamings,Yoga Yoga,Raditsis Raditsis,Reid Reid,Druce Druce,Athan Athan,Caly Caly,Liew Liew,Alexandersen Alexandersen,Vuillermin Vuillermin

doi:10.3390/v11100913

Abstract

Human parechovirus (HPeV), particularly type 3 (HPeV3), is an important cause of sepsis-/meningitis-like illness in young infants. Laboratory records identified a total of ten HPeV-positive cases in Southeastern Australia between January and July 2019. The HPeV present in these cases were typed by Sanger sequencing of the partial viral capsid protein 1 (VP1) region and selected cases were further characterised by additional Sanger or Ion Torrent near-full length virus sequencing. In seven of the ten cases, an HPeV type 5 (HPeV5) was identified, and in the remaining three cases, an HPeV type 1 was identified. The HPeV5-positive cases were infants under the age of 3 months admitted to hospital with fever, rash, lethargy and/or sepsis-like clinical signs. Near full-length virus sequencing revealed that the HPeV5 was most likely a recombinant virus, with structural genes most similar to an HPeV5 from Belarus in 2018, and a polymerase gene most similar to an HPeV3 from Australia in 2013/14. While HPeV5 is not typically associated with severe clinical signs, the HPeV5 identified here may have been able to cause more severe disease in young infants through the acquisition of genes from a more virulent HPeV.

Highlights

Human parechoviruses are rapidly evolving picornaviruses that may cause sepsis-/meningitis-like illness in infants [1]
We have previously described three epidemic waves in Australia in 2013/14, 2015/16 and 2017/18 caused by a recombinant strain of human parechovirus type 3 (HPeV3) [2]
While 2019 was predicted to be the year in which the HPeV3 epidemic in Australia was likely to occur, instead a recombinant HPeV type 5 (HPeV5) has been the predominant parechovirus infection detected in sick infants in 2019

Summary

Introduction

Human parechoviruses are rapidly evolving picornaviruses that may cause sepsis-/meningitis-like illness in infants [1]. We have previously described three epidemic waves in Australia in 2013/14, 2015/16 and 2017/18 caused by a recombinant strain of human parechovirus type 3 (HPeV3) [2] This strain of HPeV3 likely resulted from recombination of an HPeV3 Yamagata 2011 strain providing the capsid region and an unknown parechovirus providing the non-structural proteins region [3,4]. Recent studies in Europe have identified HPeV3 causing disease in young children in the United Kingdom and Germany between 2016 and 2018 with highly similar viral capsid protein 1 (VP1) sequences to the Australian recombinant HPeV3, this is only based on partial sequencing (256–807 nucleotides) of the capsid region [5,6] This may support our previous finding that this HPeV3 likely continued to circulate in people between Australian epidemics, based on the molecular evolution of the virus between epidemics [2]. In the absence of further sequencing of these European viruses, it is impossible to determine their exact HPeV3 lineage, as these viruses frequently recombine [3,7,8]

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Results

Conclusion