The CDC has issued an advisory cautioning clinicians in the United States about the rising incidence of cases caused by the human parechoviruses in many parts of the country.^1,2 The CDC has advised to include parechoviruses “in the differential diagnoses of infants presenting with fever, sepsis-like syndrome, or neurologic illness (seizures, meningitis) without another known cause and to test for PeV in children with signs and symptoms compatible with PeV infection”.

Human parechovirus infection was first reported in India in 2017.³ It has since been detected in children ≤1 year of age hospitalized for acute gastroenteritis.⁴

Some key facts about Parechoviruses^1,4

• Human parechoviruses belong to the Picornaviridae family.
• PeVs are small, non-enveloped, positive sense, single-stranded RNA viruses.
• Of the four species known, Parechovirus A (PeV-A) is the only species that causes infectionsin humans. Genotype PeV-A3 is associated with severe infection in neonates and young infants
• They are common childhood pathogens.
• Clinical presentation: Infection is often asymptomatic. In children aged 6 months to 5 years, the symptoms are fever, upper respiratory infection and rash. However, in the younger children, below 3 months of age, the infection is more severe (sepsis-like illness, seizures, meningitis or meningoencephalitis) and is potentially life-threatening. Examination of the CSF shows few or no white blood cells.
• The viruses spread via the feco-oral route or through droplets produced during coughing or sneezing. Both asymptomatic and symptomatic persons can transmit the virus.Infected persons may shed the virus from the upper respiratory tract for 1-3 weeks and from gastrointestinal tract for up to 6 months after the infection.
• The incubation period is not known.
• Similar to the enteroviruses, the parechoviruses may also show a seasonal pattern with infections more prevalent in late summer and fall.
• There is no specific treatment for the infection.
• Prevention: Thorough hand washing preferably with soap and water (alcohol-based hand sanitizer can also be used to clean hands), cough hygiene, avoiding contact with people who are sick.

References

1. Recent reports of human parechovirus (PeV) in the United States—2022, CDC, July 12, 2022.
2. CDC warns about potentially deadly virus in infants - Medscape - Jul 15, 2022.
3. Krishna Chaaithanya Itta 1, et al. First detection of human parechovirus infection with diarrhoea, India. Infect Dis (Lond). 2017 Feb;49(2):151-152.
4. Patil PR, et al.Epidemiology and genetic diversity of human parechoviruses circulating among children hospitalised with acute gastroenteritis in Pune, Western India: a 5-years study.  Epidemiol Infect. 2018 Jan;146(1):11-18.