Detection of All Known Parechoviruses by Real-Time PCR

The Parechovirus genus of the Picornaviridae family contains two species, Human parechovirus (HPeV) and Ljungan virus (LV). The HPeVs (including the former echoviruses 22 and 23, now HPeV type 1 (HPeV1) and HPeV2, respectively) cause a wide spectrum of disease, including aseptic meningitis, gastroenteritis, encephalitis, acute respiratory illness, and neonatal sepsis-like disease. The LVs were isolated from bank voles in Sweden during a search for an infectious agent linked to fatal myocarditis cases in humans. Because of the decline in use of cell culture and neutralization to investigate enterovirus-like disease, very few laboratories currently have the capability to test for parechoviruses. We have developed a real-time reverse transcription-PCR (RT-PCR) assay for detection of all known members of the genus Parechovirus. The assay targets the conserved regions in the 5' nontranslated region (5'NTR) of the parechovirus genome and can detect both HPeVs and LVs, unlike other published parechovirus 5' NTR assays, which only detect known HPeVs or only LVs. HPeV and LV can be differentiated by sequencing the 5'NTR real-time RT-PCR amplicon, when needed. The assay is approximately 100 times more sensitive than cell culture and may be used to test original clinical specimens. The availability of a broad-specificity PCR method should facilitate the detection of new human parechoviruses, as well as new parechoviruses in other mammalian species, and provide an opportunity to investigate the role of these viruses in human and animal disease.