The Epidemiology And Clinical Features Of Human Bocavirus In Children With Acute Respiratory Tract Infection In Sochow Area

Objective: To expand our understanding of the epidemiology and clinical features ofhuman bocavirus in children with acute respiratory tract infection in Sochow area.Compare the epidemiology and clinical features of HBoV infection with RSV infectionand HBoV coinfection with other pathogens respectively. To study the the relationshipbetween HBoV and climatic factors in Sochow.Method:5632samples were collected from January2009to Decermber2011, wetested respiratory specimens for the presence of HBoV by polymerse chian reaction (PCR).These specimens also assayed for respiratory syncytialvirus, influenza A and B,parainfluenze virus1to3, and adenovirus,respiratory syncytial virus by direct fluorescentantibody test, and hMPV by reverse-transcription polymerse chian reaction (RT-PCR),mycoplasma by quantitation fluorescent PCR and bacteria by cultivation. Then comparethe epidemiology and clinical features of HBoV infection and RSV infection/HBoVcoinfection with other pathogens. Climatic factors,including mean tomperature, relativehumidity, rainfall amount, sum of sunshine and mean wind velocity were collectedmonthly. The relationship between HBoV and climatic factors were analyzed by linearregression and stepwise regression analysis.Results: Of the5632patients screened,415(7.37%) patients had evidence of HBoVinfection and it was the second most common viral pathogen. Among them,128cases weresingle HBoV infection, the coinfection rate with other pathgons is66.27%.Among theHboV-positive cases,89cases (20.24%) coinfect with other respiratory virus,68casescoinfect with mycoplasma, and180cases coinfect with bacteria. The majority of HBoV-positive individuals were detected in the autumn, and the minority were in the spring. Themedian age age of HBoV-positive patients was22.10months which older than the RSV-positive patients, and a majority (55.63%) of children who tested positive for HBoV were aged from7to24months. The RSV-positive patients were more than the HBoV-positivepatients in the team who younger than7month. The majority infected children werediagnosed bronchopneumonia. Clinical symptoms associated with HBoV infection weresimilar to those associated with RSV infection. The patients who had fever in the HBoV-positive were more the RSV-positive, but those who had the symptoms cough, wheezing,dyspnea, rhinorrhea were less than the RSV-positive.The median account of white cell、theratio of neutrophilic granulocyte、the median account of CRP of the HBoV infection werehiger than those of RSV infection, and the median account of platelets of the HBoVinfection were lower than those of RSV infection. Coinfections of HBoV with otherrespiratory viruses or other pathogens were clinically similar to single infections. Therelationship between the positive rate of HBoV and the monthly mean temperature(r=0.54)、monthly recall relative humidity (r=0.491) was moderately correlated, and themonthly average rainfall (r=0.211), monthly averagesunshine duration (r=0.048), themonthly average wind speed (r=0.152) was low correlated. Analyzed by stepwiseregression analysis,the included infactors were monthly mean temperature and monthlyrecall relative humidity.Conculsion:(1) HBoV was the second most common viral pathogen of respiratory-tract disease in children in Sochow area, it prevailed predominantly in the summer andautumn.(2) Clinically, HBoV infection can not be discriminated from the infection of otherrespiratory tract viruses such as RSV. The age of patient、clinical features and X-ray ofHBoV infection was a little different from RSV infection.(3) Coinfections of HBoV withother respiratory viruses were clinically similar to single infections.(4) Climatic factors,especially the temperature and humindity may affect the prevalence of HBoV.