Parechovirus: an important emerging infection in young infants

Abstract

Epidemics of human parechovirus (HPeV) causing disease in young children have occurred every 2 years in Australia since 2013. HPeV genotype 3 caused the epidemic from late 2017 to early 2018. Most HPeV infections cause no or mild symptoms including gastroenteritis or influenza-like illness. Characteristically, young infants present with fever, irritability and on occasions a diffuse rash ("red, hot and angry" babies). Severe disease can manifest as meningoencephalitis, seizures or sepsis-like presentations (including septic shock), or less common presentations including signs of surgical abdomen. Testing for HPeV by specific molecular tests is indicated in children younger than 6 months of age with characteristic presentations without another confirmed diagnosis including febrile illnesses with other suggestive features (eg, rash, seizures), sepsis syndromes (including shock), and suspected meningoencephalitis (which may be detected by magnetic resonance imaging only). There are no effective antiviral therapies. Treatment is primarily supportive, including management of complications. Some infants with severe HPeV infection may have adverse neurodevelopment. Follow-up by a paediatrician is recommended.

Evolutionary analysis of human parechovirus type 3 and clinical outcomes of infection during the 2017–18 Australian epidemic

“…The 2017/18 HPeV epidemic was the largest epidemic by case numbers seen to date in Australia 4 . This study has found that there has been no major genetic changes (ie recombination) in the predominant HPeV3 circulating in Australia, nor has there been a change in the capsid protein structure or antigenicity of the virus circulating that may explain the increased incidence of the disease in 2017.…”

“…In late 2017 to early 2018, the largest HPeV epidemic to date occurred. A large number of cases were initially seen in Victoria in south eastern Australia, before a similar increase in cases appeared in other states 4 . 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.…”

“…Highly symptomatic cases were recognized in Sydney, Australia, and also detected nationally in 2013/14 16–18 . It was again seen in epidemics in 2015/16 19 and more recently in 2017/18 4 . The earliest published HPeV3 positive sample in Australia was collected from a sick infant in 2012 20 .…”

“…HPeV infection is often asymptomatic, or associated with mild respiratory or gastrointestinal disease in children. However some types, 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) 2–4 . Of children with severe CNS symptoms or sepsis-like disease caused by HPeV3, 25–50% will require intensive care admission 5 .…”

“…In Australia, epidemics of HPeV3 have appeared to be larger than those observed in other countries and associated with poorer clinical outcomes 4 . In late 2017 to early 2018, the largest HPeV epidemic to date occurred.…”