Detection of Spliced mRNA from Human Bocavirus 1 in Clinical Samples from Children with Respiratory Tract Infections

Andreas Christensen

, Henrik Døllner, Lars Høsøien Skanke, Sidsel Krokstad, Nina Moe, and Svein Arne Nordbø

Author affiliations: Trondheim University Hospital, Trondheim, Norway (A. Christensen, H. Døllner, L.H. Skanke, S. Krokstad, N. Moe, S.A. Nordbø); Norwegian University of Science and Technology, Trondheim (A. Christensen, H. Døllner, N. Moe, S.A. Nordbø)

Abstract

Human bocavirus 1 (HBoV1) is a parvovirus associated with respiratory tract infections (RTIs) in children, but a causal relation has not yet been confirmed. To develop a qualitative reverse transcription PCR to detect spliced mRNA from HBoV1 and to determine whether HBoV1 mRNA correlated better with RTIs than did HBoV1 DNA, we used samples from HBoV1 DNA–positive children, with and without RTIs, to evaluate the test. A real-time reverse transcription PCR, targeting 2 alternatively spliced mRNAs, was developed. HBoV1 mRNA was detected in nasopharyngeal aspirates from 33 (25%) of 133 children with RTIs but in none of 28 controls (p<0 .001="" a="" analytical="" and="" as="" be="" benefit="" cause="" could="" data="" diagnostic="" dna="" good.="" hbov1="" hypothesis="" instead="" may="" mrna="" of="" our="" p="" propose="" rtis="" sensitivity="" specificity="" support="" target.="" test="" that="" the="" used="" we="" were="" with="">

Human bocavirus 1 (HBoV1) is a small nonenveloped virus in the Parvoviridae family. It was discovered in human respiratory samples in 2005 (1). The virus does not grow in standard cell lines, and diagnosis has mainly been based on DNA detection with PCR. Detection of multiple viruses in HBoV1 DNA–positive airway samples from children with respiratory tract infections (RTIs) has been a characteristic finding in many studies (2–4). In addition, many healthy children have tested positive for HBoV1 DNA (2,5); thus, whether the virus actually causes RTIs in children or is just a bystander to other infections has been debated. However, we have shown that the following 3 factors are associated with RTIs: HBoV1 viremia (HBoV1 DNAemia), a high HBoV1 DNA load in nasopharyngeal aspirates (NPAs), and monodection of HBoV1 DNA in NPAs (5). In addition, RTIs in HBoV1 DNA–positive children are associated with HBoV1 seroconversion (6). This evidence supports a causal relation between HBoV1 and RTIs in children, but DNA-based PCR tests do not seem to diagnose HBoV1 infection accurately. We propose that detection of HBoV1-specific mRNA, as a measure of actively transcribing virus, may be a better method.
The main objectives of this study were to develop a qualitative reverse transcription PCR (RT-PCR) detecting spliced mRNA from HBoV1 and to clarify whether HBoV1 mRNA detection may correlate better than DNA detection with RTIs in children. NPAs and blood samples from a group of children, with and without RTIs, who tested positive for HBoV1 DNA were used for this purpose.