| ObjectiveTo study the clinical and molecular epidemiology characteristics of related pathogens of acute respiratory tract infections (ARTls) in children in Lanzhou area from December 2009 to November 2010. focusing on monitoring the human metapneumovirus, human Bocavirus. mycoplasma pneumonia. To accumulation data on the etiology of acute respiratory infection epidemiological study in Lanzhou. To provide the basis for clinical anti-infection treatment.At the same time, We carried out real-time fluorescence quantitative PCR method in the detection of respiratory pathogens.Subjects and Methods1 Nasopharyngeal aspiration(NPA) samples and throat swabs were collected from 545 children with ARTI at the First Hospital of Lanzhou University, Gansu Province, China, between December 2009 and November 2010.2 Real-time quantitative RT-PCR was used to detecte human metapneumovirus; Nested PCR was used to detecte human Bocavirus; RT-PCR and standard PCR were employed to screen ten respiratory infection-associated viruses, Including ADV, RSV. IFV (A, B), HRV, PIV (1-3), HCOV-NL63, HCOV-HKU1. Then the amplicons were sequenced and phylogenetic analysis was conducted. Combined with four years of continuous research datas. we analyzed the epidemiological characteristics associated virus3 Real-time quantitative RT-PCR was used to detecte Mycoplasma pneumoniae in NPA. We analyzed the clinical data of positive patients, to understand the prevalence and epidemiolog of Mycoplasma pneumoniae.Meanwhile. to study the clinical and molecular epidemiology characteristics in Nanjing area with the same method. By comparing datas from the two regions. to preliminary understand the molecular epidemiology differences of Mycoplasma pneumoniae infection of the in eastern and western China.Results 1 In this study, we detected 54 cases of human metapneumovirus-positive specimens, the detection rate was 9.91%, ranking forth in our study viruses. The average viral load of positive samples was 4.88109 copies/ml;The specimens which viral load was more than 106 copies/ml accounted for 72.22%. By genotyping of matrix protein,21 cases (38.89%) were typed. The results of phylogenetic analysis showed:A2b were the dominant type (47.62%) in the study year. Moreover, A2b type has been the dominant type in the last four years.The detected rate was no signification difference between male and female. The peak detection period was from March to May. Positive cases less than 1 year of age were the largest proportion of all positive. The detection rate of more than 2 years of age has a declining trend.57.41% of HMPV-postive cases were found coinfected with other viruses, RSV(38.71%) and PIV3(35.48%)were the common mixed infection virus. The detected rate was no signification difference between AURI and ALRI. HMPV-positive children are more vulnerable to wheezing.2 Among the 545 samples, we detected 54 cases(8.26%) of HBoV-positive specimens which includes 41 cases of HBoV1(7.52%),3 cases of HBoV2(0.55%),1 cases of HBoV3(0.18%), HBoV4 was not detected. The detected rate of HBoV1 was no signification difference between male and female. The detection rate of summer (July～September) and winter (November to January next year) was higher. The peak detection rate was in July, the detection rate was 14.29%.Among under 1 year old group,24 cases which infected HBoV1 were detected, the detection rate was 8.63%,;the number and rate occupied the first place in all age groups. HBoV-positive cases had a higher coinfected rate(65.82%).The detection rate of HBoV1 in children with lower respiratory tract infection was 9.14% (33/361), significantly higher than the detection rate 4.35% (8/184) in children with upper respiratory tract infection (x2=4.025. P=0.045<0.05). The clinical manifestations were no signification difference between single HBoV1-positive and coinfected HBoVl-positive. All HBoV2/3-positive cases were coinfected.Three HBoV2-positive cases have diarrhea symptoms.3 The rate of total viruses detection was 62.94%(343/545). ranking top three were HRV (108,19.82%), RSV(106,19.45%), PIV3 (66.12.11%).,respectively.The detected rate was no signification difference on gender and season. On the age distribution, children 7 to 12 months had the highest detection rate (70.84%). The detection rate of more than 3 years of age has a declining trend.4 After comparing and analysising the molecular epidemiology characteristics of four study years.we found the following trends:(1) In the past three years. RSV is the highest detection rate virus, followed by HRV;However. HRV jumped to the first. RSV placed second in this research year.And the detection rate of HRV in this research year was the hightest. (2) In the past four years, the detection rate of influenza virus type B increased year by year(1.50%-2,70%→4.90%→5.14%).(3) In the past four years, parainfluenza virus 1-2 were barely detectable; parainfluenza virus 3 was predominant and common subtype in Lanzhou,.And the detection rate had an increasing tendency in the last two years.(4) The incidence rate of Coronavirus HKU1 in the last two years were 0.40% (2008.12～2009.11),0.37%(2009.12～2010.11) respectively,It was significantly lower than 3.00%(2006.12～2007.11),4.30% (2007.12～2008.11) in the previous two years (x2=25.224, P<0.01)5 The incidence rate of mycoplasma pneumonia(10.51%,39/371) in Lanzhou area was significantly lower than the incidence rate(22.20%,95/428) in Nanjing area (x2= 19.437, P <0.01). The average load of positive samples in Lanzhou and Nanjing were 4.21×108 copies /ml and 3.01×107 copies/ml respectively.The samples more than 106 copies/ml in Lanzhou was significantly lower than in Nanjing. On the seasonal distribution, the epidemic seasons of two region were in summer,fall and early winter. On the age distribution, the MP-postive cases accounted for more than 60% in over 5 years children between Lanzhou and Nanjing. The incidence rate of under 1 years of age in Nanjing was significantly higher than in Lanzhou (x2=26.558, P<0.01). Lower respiratory tract infections were the main diagnostic between two regions.Conclusion1 The detected rate of human metapneumovirus ranked forth in related viral pathogens of acute respiratory infections during this research year. A2b was the dominant type in the study year,and was the major type in the last four years.There are remarkable seasonal distribition of HMPV in Lanzhou area, The peak detection period was from March to May.2 The HBoV3 was detected at the first time in lanzhou area.HBoVl-3 infection exists in children with acute respiratory tract infections in Lanzhou region, HBoV1 were dominant(7.53%). The mixed infection rate was higher.3 In this research year. viral infection was the main reason for children with ARTIs in lanzhou area, top three viruses were HRV,RSV,PIV3; The detected rate of HRV jumped as the first, RSV placed second.4 Mycoplasma pneumoniae was an important pathogen in lower respiratory tract infection in children and has a higher mixed infection rate. The detection rate of Nanjing area was significantly higher than in Lanzhou. On the seasonal distribution, the epidemic seasons of two region were in summer.fall and early winter. On the age distribution.the age of postive csaes trend in younger age obviously in Nanjing. |
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