A novel pancoronavirus RT-PCR assay: frequent detection of human coronavirus NL63 in children hospitalized with respiratory tract infections in Belgium

Background: Four human coronaviruses are currently known to infect the respiratory tract: human coronaviruses OC43 ( HCoV- OC43) and 229E ( HCoV- 229E), SARS associated coronavirus ( SARS- CoV) and the recently identified human coronavirus NL63 ( HCoV- NL63). In this study we explored the incidence of HCoV- NL63 infection in children diagnosed with respiratory tract infections in Belgium. Methods: Samples from children hospitalized with respiratory diseases during the winter seasons of 2003 and 2004 were evaluated for the presence of HCoV- NL63 using a optimized pancoronavirus RT- PCR assay. Results: Seven HCoV- NL63 positive samples were identified, six were collected during January/ February 2003 and one at the end of February 2004. Conclusions: Our results support the notation that HCoV- NL63 can cause serious respiratory symptoms in children. Sequence analysis of the S gene showed that our isolates could be classified into two subtypes corresponding to the two prototype HCoV- NL63 sequences isolated in The Netherlands in 1988 and 2003, indicating that these two subtypes may currently be cocirculating