Epidemiological Characteristics And Clinical Research Of Human Bocavirus With Respiratory Tract Infection In Hospitalized Children In Suzhou Area

ObjectivesTo study the epidemic characteristics of human bocavirus with acute respiratory tract infection in hospitalized children and its relationship of meteorological factors in suzhou,and to explore the clinical characteristics of h BoV infection.Methods8711 cases involving the hospitalized children with respiratory tract infection were obtained from January 2012 to December 2015 in department of respiration,Children's Hospital Affiliated Soochow University.The method of sterile negative pressure suction was used to collect nasopharyngeal secretions.Human bocavirus was detected by real-time fluorescent PCR.Human metapneumovirus(hMPV)was tseted with reverse transcription polymerase chain reaction(RT-PCR),direct immunofluorescence assay was used to detect 7 common viruses in respiratory tract including respiratory syncytial virus(RSV),influenza virus type A and B(InfA,B),Parainfluenza virus type 1,2,and 3(Pinf?,?,?),adenovirus(ADV).Meanwhile,some meteorological data were collected such as monthly average temperature(?),monthly mean humidity(%),monthly precipitation(mm),monthly total sunshine time(h)?monthly mean wind speed(m/h)etc.from January 2012 to December 2015 in Suzhou area,the relationship between the detection of human bocavirus and metrorological factors was analyzed by linear regression and stepwise regression analysis.Results1.2594 cases(29.78%)were positive among 8711 cases,the top five detected virus were RSV 933 cases(10.71%)?hRV 666 cases(10.52%,666/6333)?hBoV358 cases(4.11%)?Pinf? 316 cases(3.63%)?hMPV 101cases(1.16%).2.The positive rates were respectively 1.23%,7.62%,8.83%,2.78% and 3.47% among the children who were less than 6 months,6 to 12 months,1 to 2 years old,2 to 5 years old,and more than or equal to 5 years old.6 to 12 months,1 to 2 years group of children with higher detection rate than other age groups.3.The annual detection rate of h BoV in 2012 to 2015 was 3.39%,4.40%,3.81%,and 4.31% respectively.There was no significant difference in the detection rate of hBoV between the four years(?2 = 1.297,P > 0.05).4.The detection rate of hBoV was 2.38%in spring,5.31% in summer,6.36% in autumn,2.53% in winter,which was statistically significant in different seasons(?2= 65.289,P <0.001).Positivity rate of summer was higher than that of spring and winter(?2= 25.857,22.300,P <0.001).Positivity rate of autum was higher than that of spring and winter(?2= 41.926?37.191,P <0.001).These data revealed that the prevalence of hBoV infection was obviously higher during summer and autumn than in spring and winter.5.Among 358 cases of hBoV-positive children,there were 4 cases(1.12%)of upper respiratory tract infection,4 cases(1.12%)of bronchitis,3 cases(0.84%)of bronchilitis,288 cases(80.45%)of bronchopneumonia,30 cases(8.38%)of lobar pneumonia,and 29 cases(8.10%)of severe pneumonia.The main clinical manifestations were cough(97.77%),fever(61.45%),wheezing(51.96%),stuffiness and / or runny nose(37.43%),shortness of breath(13.97%),dyspnea(5.59%),lung rales(88.55%),chest radiograph abnormalities(98.89%).6.The average age of children with severe pneumonia caused by hBo V was 11.6±0.9 months,all of them were under 2 years old,3 cases had underline disease and 8 cases were coinfection with other pathogens among them.7.92 cases of hBoV-positive children had mixed infection,the top three of which including 41 cases of hBoV+hRV,30 cases of hBoV+RSV,9 cases of hBoV+Pinf ?.8.The detection rate of hBoV had moderate and positive correlation with monthly mean temperature(r=0.443,P=0.002),low correlation with monthly sunshine time(r=0.166,P=0.260).Conclusions1.hBoV is one of the most important pathogens of respiratory tract infection among children in Suzhou area.The detection rate of children with the age between 6 to 12 months and 1 to 2 years group is higher.2.The prevalence of hBoV infection was higher during summer and autumn.3.The clinical manifestations of hBoV infection has no obvious specific characteristics compared with other respiratory virus.4.hBoV can cause severe pulmonary infection,occurring mainly in children under 2 years old.5.Co-infection was common in patients with hBoV infection.The common pathogen co-infected was hRV and RSV.6.The positive rate of hBoV has moderate and positive correlation with monthly mean temperature.