What is the issue?
Human parechovirus (HPeV) belongs to the Picornaviridae family of viruses. An uncommon strain of HPeV type 5 has been detected in Victoria. Six cases of HPeV type 5 have been identified since February 2019. All cases have been in neonates. The last HPeV epidemic in Victoria, caused by the related HPeV type 3, occurred from late 2017 to early 2018. Epidemics of HPeV causing disease in young children have been identified every two years in Australia since 2013.
Most infections caused by HPeV are mild or asymptomatic, however severe disease manifests as neonatal sepsis-like syndrome and meningitis. The detailed clinical manifestations of this current strain of HPeV type 5 are yet to be ascertained, however available information is consistent with neurological disease in most of the known cases.
HPeV are closely related to enteroviruses but are not detectable in standard enterovirus polymerase chain reaction (PCR) tests. For this reason, specific parechovirus testing needs to be undertaken.
Human parechovirus infection is not a notifiable condition in Victoria.
Who is at risk?
HPeV infection occurs commonly in the general population. Children are more likely to develop symptoms, and neonates and young infants are at risk of more severe disease.
Consider HPeV as a differential diagnosis, and consider specific parechovirus PCR, in neotates and young infants presenting with meningoencephalitis or a sepsis-like syndrome.
Symptoms and transmission
Most people infected with HPeV experience no symptoms (50-80 per cent). Some people may develop a mild gastrointestinal or respiratory illlness characterised by diarrhoea, cold and flu-like symptoms and fever.
Some strains of HPeV can lead to more severe disease such as sepsis-like syndrome, meningitis, encephalitis, flaccid paralysis, seizures and hepatitis. Infants, particularly under the age of 3 months, are more likely to develop severe disease. They may become unwell very quickly and present with fever, irritability, tachycardia, pain, drowsiness, lethargy and an erythematous skin rash.
HPeV is usually spread from person to person through contact with respiratory droplets, saliva or faeces from an infected person. It can also be spread through inanimate objects and surfaces that have been contaminated with infected secretions.
HPeV is not detected by standard enterovirus polymerase chain reaction (PCR) tests used at most pathology services. In addition, cerebrospinal fluid (CSF) may not display pleocytosis (an increase in lymphocytes) in HPeV infection. Therefore, the diagnosis of HPeV infection should be considered in neonates and young infants with a clinically compatible illness and parechovirus PCR should be specifically requested. This may be available locally in a limited number of laboratories. If not, the testing may be accessed through the VIDRL.
VIDRL tests for HPeV whenever enterovirus testing is requested (dual testing) and can be performed on stool specimens, nasopharyngeal aspirates or throat swabs, CSF or whole blood samples (collected in an EDTA tube). Stool and CSF are the preferred samples.
Laboratories should consider automatically sending to VIDRL for HPeV testing, all CSF samples in infants less than 6 months of age when enterovirus PCR has been requested.
There is no specific treatment available. Treatment is aimed at supportive care and symptom relief. Severely unwell cases need to be assessed and treated for suspected sepsis under the care of an emergency consultant or paediatrician.
The best way to prevent parechovirus infection is the same as for prevention of all viral gastrointestinal illnesses. Hand hygiene and contact precautions should be inplemented (including gloves, gown, plastic apron, mask and eye protection).
For the public, good hygeine is the best protection. This includes hand washing, cough ettiquite, cleaning of soiled clothing and surfaces, and social distancing when unwell.
There is no vaccine to protect against HPeV infection.
HPeV infection is not a notifiable condition in Victoria. The Victorian Department of Health and Human Services works with clinicians and VIDRL to monitor outbreaks of severe cases.
Better Health Channel – Parechovirus
For more information please contact the Communicable Disease Prevention and Control section at the Department of Health and Human Services on 1300 651 160 (24 hours).