What is the issue?
Human parechovirus belongs to the Picornaviridae family of viruses. There has been a large increase in the number of HPeV cases detected at the Victorian Infectious Diseases Reference Laboratory (VIDRL) since July 2017 when compared to the previous year. At this point case numbers are similar to those observed in the spring of 2015. Most cases have been in young children and infants. This is the third such increase in Victoria and reflects research from the UK that suggests parechovirus tends to occur in two yearly epidemics.
Human enteroviruses (EVs) and more recently parechoviruses (HPeVs) have been identified as leading viral causes of neonatal sepsis-like disease and meningitis.
Like enteroviruses, HPeV infection has a seasonal pattern, with a higher number of cases during the spring, summer and autumn months, in line with other gastrointestinal illnesses.
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 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 to 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.
Diagnosis and treatment
HPeV is not detected by standard enterovirus polymerase chain reaction (PCR) tests used at most pathology services. In addition, CSF may not display pleocytosis (an increase in lymphocytes) in HpeV infection. Therefore, in cases of severe clinically compatible paediatric illness, parechovirus PCR should specifically be requested. This may be available locally in a limited number of laboratories. If not, the testing may be accessed through the Victorian Infectious Diseases Reference Laboratory (VIDRL).
VIDRL tests for HPeV whenever enterovirus testing is requested (dual testing) and can be performed on stool specimens, nasopharyngeal aspirates or throat swabs, cerebrospinal fluid (CSF) or whole blood (EDTA). 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 - Human 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.
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