Human parechovirus (HPeV) belong to the family of Picornaviridae. HPeV infections result in a variety of symptoms ranging from mild respiratory and gastrointestinal symptoms to sepsis-like syndrome and meningitis, especially in young children. Clinically, HPeV infections cause similar symptoms as enterovirus (EV) infections. EV is routinely performed in the laboratory but not for HPeV. Molecular assays diagnosing EV will not be able to detect HPeV due to lack of sequence conservation between EV and HPeV in the 5’-UTR region of the genome. Hence, it is important to introduce a method to detect HPeV, as severe illnesses resulting from HPeV infections may go undetected. Literatures were adapted in our laboratory to allow the concurrent detection of both EV and HPeV.
Nucleic acid extracts from 300 consecutive cerebrospinal fluid (CSF) samples previously submitted for EV qualitative real-time polymerase chain reaction (qRT-PCR) assay were tested. Amplification and detection of HPeV by qRT-PCR was carried out in a Rotor-Gene (Qiagen, Hilden, Germany) instrument. CSF white blood cell (WBC) counts and glucose concentration data was recorded.
Of the 300 CSF samples, 35 (11.6%) were positive for EV, and 23 (7.6%) were positive for HPeV. In general, EV-positive samples showed higher pleocytosis while HPeV-positive samples did not No significant differences were observed in the glucose concentration in all the categories tested, namelya) EV-positive, b) HPeV-positive and c) Negative samples. No co-infection of EV and HPeV observed in this study.
As HPeV infections generally do not cause CSF pleocytosis, clinical diagnosis and routine CSF findings may overlook the possibility of HPeV infections. By introducing dual EV-HPeV testing, we can fill this diagnostic gap. This will be particularly relevant for neonates and small infants, as HPeV infections may present with a severe sepsis- and meningitis-like clinical picture in this age group.