Detection And Analysis Of HCoV-HKU1,HCoV-OC43 And RSV In Children With Acute Respiratory Tract Infections In Fuzhou Area

ObjectiveTo investigate the prevalence and clinical feature of the novel human coronavirus HKU1 (HCoV-HKU1),Respiratory Syncytial Virus(RSV) and human coronavirus OC43 (HCoV-OC43) in children with acute respiratory infections in Fuzhou area.MethodsA total of 176 nasopharyngeal swab samples were collected from children who visited Fujian Provincial hospital with acute respiratory tract infections during the period of Dec.2006 to Apr.2007. Of the 176 samples,115 were from children with upper respiratory tract infections,61 were from lower respiratory tract infections.Single Reverse Transcription-Polymerase Chain Reaction(RT-PCR) and multiplex RT-PCR(mRT-PCR) were both used for the detection of the RNA pol gene of HCoV-HKU1,S gene of HCoV-OC43 and N gene of RSV.These two methods were also used for the subgroups detection for the RSV positive sample.The PCR products with expected molecular mass were selected ramdomly for DNA sequencing,and then sequences from those PCR products were compared with the sequences of reference strain in the GenBank.Homological analysis and phylogenetic analysis were also performed for the sequences of HCoV-HKU1 and HCoV-OC43.Results1. Of the 176 samples,RSV was detected in 28(15.9%),HCoV-OC43 in 9(5.1%), HCoV-HKU1 in 1(0.6%).2. The only sample infected with HCoV-HKU1 was co-infected with RSV.3. Two out of nine HCoV-OC43 PCR products were randomly selected for sequence analysis.Their nucleotide sequences were consistent with each other.This nucleotide sequence was over 96% homology with that of the reference strains in the GenBank,and the amino acid sequence was consistent with that of the reference strains.4. The nucleotide sequence of the HCoV-HKU1 PCR products sequenced was over 99% homology with that of the reference strains in the GenBank.And the amino acid sequence was 100% homology with that of the reference strains.The phylogenetic tree based on the nucleotide sequence of the PCR products showed that, this HCoV-HKU1 strain had the closely relationship with HCoV-HKU1 genotype C refrence strain whose accession number in Genbank is DQ415913.5. Among 28 RSV positive samples.The RSV positive rate in lower respiratory tract infections group was 38%(23/61),and this was significantly higher than 4%(5/61) in upper respiratory tract infections group (x2=33.15,P<0.05).6. Subtypes analysis for 28 RSV positive samples showed that subtype A was detected in 23(82%),subtype B in 4(14%),unclear type in 1(4%).No significant difference was found in the prevalence of RSV subtypes between upper and lower respiratory tract infections groups(P>0.05),subtype A predominated in both groups.7. RSV positive samples were predominantly from children aged less than 3 years old.Conclusions1. RSV and HCoV-OC43 were the important pathogens in children with acute respiratory tract infections in Fuzhou from winter 2006 to spring 2007.HCoV-HKU1 may have correlation with lower respiratory tract infections of children in Fuzhou area.2. RSV co-infections with HCoV-HKU1 may be contribute to the aggravation of respiratory tract infections in children.3. RSV mainly caused lower respiratory tract infections,especially in infants aged less than 3 years old.4. The subgroups A and B of RSV were both circulating,with subgroup A predomin -ated in Fuzhou from winter 2006 to spring 2007.5. The multiplex RT-PCR can substitute for single RT-PCR in the detection of HCoV-HKU1, HCoV-OC43 and RSV.