Clinical Research Of Bronchiolitis Caused By Human Bocavirus

ObjectiveOur previous studies had confirmed that human bocavirus(HBoV) was one of the pathogensin bronchiolitis. On the basis of the results of the previous studies, now, we focuses on theclinical characteristics of human bocavirus, to provide a theoretical basis for the clinicalprevention and treatment of bronchiolitis.Materials and methodsTotally 271 throat swab samples were collected from children with bronchiolitis hospitalizedin the department of pediatrics in second affiliated hospital of Shantou university medical collegefrom June, 2007 to May, 2008. 82 throat swab specimens were collected among the healthychildren. The children' age, gender, clinical symptoms, signs, laboratory examinations and otherclinical data were also collected for analysis of the clinical characteristics, while assessing theseverity of the illness of each patient. All of the throat swab samples were used to detect HBoV,respirotary syncytial virus(RSV), adenovirus(ADV), rhinovirus(RhV), influenza virus A,B(IVA,IVB), parainfluenza virus 1,3(PIV1, PIV3), and human metapneumovirus (hMPV) by using themultiplex polymerase chain reaction(multi-PCR). Five HBoV gene positive PCR products wererandomly selected for purified and sequenced. Nucleotide sequences alignment and phylogeneticanalysis were performed with DNAstar software. 28 patients from RSV positive samples wererandomly selected to be in control group. The clinical characteristics of bronchiolitis, such assymptoms, signs, severity of the illness, complications, laboratory examination, and hospitalizeddays which induced by HBoV was analyzed and compared with the control group. SPSS 13.0software was used for statistical analysis, if P<0.05 was considered statistically significant.ResultsOverall at least one respiratory virus was detected in 163 of 271 samples (60.1%). Amongthem, the RSV infection accounted for 37.4 Gene sequence analysis showed that, the gene sequence of five cases HBoV-positive samples,which were randomly selected, homology of 92.4% to 99.7%. Compared with the Stockholm1(st1), fragment corresponding nucleotide homology of 81.8% to 98.4%, with st2, 82.9% to99.7%. Between the two groups, except the epidemic season, the clinical data showed that nodifferences were found in age, gender, symptoms, physical signs, white blood cell count(WBC),c-reactive protein(CRP), radiological findings, hospitalized days and severity of the illness. Theseverity of the illness was mild or moderate, mostly mild. There were no complications, severecases or mortality. Single infection of HBoV or mixed infection of HBoV and other respiratoryviruses not related to the severity of the illness.ConclusionsThere are some differences in the clinical characteristics of bronchiolitis between HBoV andRSV infection, but it is difficult to differentiate HBoV infection from RSV infection justaccording to the clinical manifestation. The symptoms of bronchiolitis caused by HBoV weremild. The severity of the illness was mild or moderate, mostly mild. In our study, there were nocomplications, severe cases or mortality in bronchiolitis that caused by HBoV or RSV.