BACKGROUND: Enteroviruses (EV) are an important cause of neonatal disease 
including hepatitis, meningoencephalitis, and myocarditis that can lead to death 
or severe long-term sequelae. Less is known about severe neonatal infection 
caused by the parechoviruses (PeV) of which type 1 (PeV1) and type 2 (PeV2) were 
previously known as echovirus 22 and echovirus 23. They belong to the same 
family of Picornaviridae as the EV. Of the PeV, so far only PeV3 has been 
associated in 2 recent reports with severe neonatal infection including 
involvement of central nervous system.
METHODS: We compared the clinical signs, diagnosis, laboratory data, cerebral 
imaging, and neurodevelopmental outcome of 11 neonates with PeV infection with 
21 infants with EV infection treated in our hospital between 1994 and 2006. The 
diagnosis of EV infection or PeV infection was confirmed by a positive EV and/or 
PeV real time-polymerase chain reaction on blood, cerebrospinal fluid, (CSF) or 
stool or a viral culture of stool, nasopharyngeal swab, and/or CSF.
RESULTS: The 32 infants presented with sepsis-like illness and the most frequent 
signs were: fever, seizures, irritability, rash, and feeding problems. All 
patients received antibiotic treatment. Eleven of 21 infants infected with EV 
and 7 of 11 infants infected with PeV were full-term. Differentiation between 
the infants infected with EV and PeV on the basis of fever, irritability, rash, 
and seizures was not possible. Myocarditis was exclusively seen in 4 patients 
infected by EV. Eight of 11 patients with a PeV infection had 
meningoencephalitis of whom only 1 infant developed pleocytosis in the CSF. 
Serum C-reactive protein and CSF protein values were significantly higher in 
infants with EV infection than in those with PeV infection. Cerebral imaging of 
all infants with EV or PeV cerebral infection showed mild to severe white matter 
abnormalities. In 1 infant with EV infection and 3 infants with PeV infection, 
neurodevelopmental delay occurred. Mortality and long-term sequelae were mainly 
associated with myocarditis in the infants who were infected with EV (4 of 21).
CONCLUSIONS: It is not possible to distinguish neonatal PeV from EV infection on 
the basis of clinical signs. Neonates with PeV or EV infection present with 
sepsis-like illness and the most frequent signs are fever, seizures, 
irritability, rash, and feeding problems.