Research On The Relationship Between Human Bocavirus And Acute Respiratory Infections In Childen In Fuzhou Area

Objective To investigate whether the novel human bocavirus(HBoV),which was identified recently by two scientists in Sweden in September 2005,is related to acute respiratory infections in pediatric patients in Fuzhou area.Methods From March 2006 to February 2007, a total number of 156 nasopharyngeal swab samples were collected. Those specimens were screened for HBoV by a PCR assay targeting 291 base pairs in the NS1 gene. PCR products were visualized by 1.5% agarose gel electrophresis. 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 HBoV in the GenBank. Those samples showed positive results in HBoV PCR were tested for RSV by a reverse transcription PCR (RT-PCR) reaction.Results 1. HBoV infection was detected in 9(5.8%) of 156 study subjects. All of the 9 samples were negative in RSV detection by RT-PCR.2. The 156 patients include 102 males and 54 females (sex ratio: 1.9 to 1). The 9 HBoV positive patients include 6 males and 3 females. The positive rate for males is 5.9%(6/102)and for females is 5.6%(3/54).The positive rate of males and females has no significant difference(X2test,P>0.05).3.The positive rate was 9.4% (3/32)among specimens collected from patients with bronchiolitis, followed by patients diagnosed as bronchitis(6.7% , 1/15). The positive rate was 3.8%(2/52)among patients with bronchopneumonia and 12.5% (1/9) among patients with asthma.4. Age distribution of the children positive for HBoV was from 10 months to 3 years old. The positive rate for HBoV detection was 4.8% among those aged from 0 to 1 years old, 7.0 % among those aged from 1 to 3 years old and 9.7 % among those aged from 3 to 5 years old. Neither of 16 infants younger than 10 months nor 17 children older then 5 years was positive for HBoV.5. HBoV was detected in January-February and in October-December. No HBoV-positive specimens were obtained in March-September.6. Three out of 9 PCR products were randomly selected for sequence analysis. The product shared high nucleotide sequence homology with the two prototype strains-- Stockholm1 1(st1, 99.3%) and Stockholm 2 (st2, 99.7%) when compared with their sequences. The result of phylogenetic trees showed that the PCR products had a closer relationship with st2.Conclusions1.These data suggest that some of acute respiratory infections in little children in Fu Zhou area. are related to the newly identified Human Bocavirus .2. HBoV is more epidemic during the autumn and winter months (October to February), the infants and young children get infected more easily. There was no difference between the incidences of male and female patients.