| ObjectiveRespiratory virus is the most common pathogens causing respiratory infections. The purpose of this study is to detect13common respiratory viruses:Respiratory syncytial virus (RSV), Human rhinovirus (HRV), Human Adenovirus (ADV), Human Bocavirus (HBOV), Human metapneumovirus (HMPV), Influenza virus A (IFVA) and B (IFVB), Human Parainfluenza virus1-4(HPIVI, HPIV2, HPIV3, HPIV4), Human coronavirus HKUI and NL63. and understand its prevalence, as well grasp the epidemiological characteristics and clinical features,in addtion to provide a reference for Prevention and treatment of respiratory tract infections(RT1) of children in lanzhou, Human Enterovirus (EV), since its discovery, was widespread all over the world and numerous outbreaks have occurred in many countries, cause studying boom of scholsrs.In this study, we applied real-time PCR method for detection of HEV, and used common primer targetd its5’untranslated region for genotyping analysis, and understanding its infection and prevanlence.Methods1. we collected545nasopharyngeal aspirates (NPA) from hospitalized children with acute respiratory tract infections(ARTI) at the First Hospital of Lanzhou University, department of pediatrics from December of2010to November of2011. Of which the boys354,191of girls, ratio of boys to girls was1.85:1, age ranged from20minutes to14years old.7～8cm up to the nasopharynx using disposable sterile suction tube is inserted from one side nose of children since admitted to hospital the same day or within three days, or changes in condition, then draw2ml of nasopharyngeal secretions and stored in viral transport medium, finaly stored in-80℃low temperature refrigerator.2. We detected RSV, HRV, IFVA, IFVB, PIV3, HMPV, HCoV-HKU1, HCoV-NL63by RT-PCR and ADV, HBOV, HPIV1, HPIV2, HPIV4by nested-PCR. Combined with continuous research data in the region between2006-2011, analysising the prevanlence of associated virus.3. Using Real-time quantitative PCR to detect EV of545NPA, And directly genotyped by secpuencing the product of a RT-PCR targected5’untranslated region.Phylogenetic analyses of the nucleotide of5’untranslated region were conducted with MEGA4.0software, respectively.Results1.RSV was the most commonly identified pathogens with detection rate of37.06%. winter and spring was its epidec season and peaking in January and February.The percentage of virus detections that under3years of age was highest. Pneumonia was account for92.57%in202children in whom RSV were detected, with cough (98.02%), fever (52.97%), wheezing (50%) as the main symptoms. Sputum culture results showed that the co-infection rate with the bacteria was45%, of which Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae, parainfluenza Haemophilus were the most common bacteria. In the past five years continuous detection of Respiratory virus in Lanzhou, the detection rate of RSV was ranged from19.45%to41.50%, peaking in winter and spring. It was observed that significantly higher number of children below3year of age. There was no difference between male and female on the detection rate. Children infectioned with RSV presented predominantly with pneumonia and bronchiolitis in this study.2.22.98%of the hospitalized children under5years of age in this study were infected with HPIV, and the detection rate was21.10%in which the HPIV3(10.09%) was most common, ranking fifth of all positive cases. Among all children infected with HPIV3,the positive cases were only detected in children under5years of age and mainly observed in less than1year old. Mixed infection rate with bacteria was52.83%. In the present study, we detected6.06%HPIV1cases, the detection rate of all ages was not statistically significant (χ2=3.387, P=0.495) popular in summer and autumn, as the highest detection rate was in October, followed by august, bacteria and viruses mixed infection rate was42.42%,1.1%of children enrolled in the study were infected with HPIV2, the infection rate were higher between6to12month than other age groups, peaking in June. The detection rate of HPIV4was6.24%, ranking second among HPIV. and was the sixth most frequently detected viral pathogen in our study. The majority of HPIV4infection occurred in spring, the difference between all age groups was not significant(P>0.05). Overall, most of HPIV1, HPIV3, HPIV4positive children were found to be coinfected with other respiratory virus. Mostly, HPIV infected children presented commonly with cough, sputum, wheezing, fever, catarrh symptoms. Additionally, most HPIV1and HPIV4infection in children accompanied with fever, and about half of CRP testing ptompted positive. The majority children infected with HPIV were more commonly associated with pneumonia than bronchiolitis. no difference between four types (P>0.05). HPIV3was the most common serotype during Five consecutive years in lanzhou, HPIV1was only detected in2006-2007(2cases) and this year, first detected HPIV2(1.1%), respectively.3.Out of545specimens, we detected HEV11(2.02%), the ratio of boys to girls was1.75:1, the difference of positive rate among male and female was not significant (P=1.000). HEV infection were scattered throughout the study period. HEV had no strong seasonal patterns (Fisher=6.543, P=0.056). Of all HEV cases, CVA was detected in3, PV in1, EV68in3, EV71in2, ECHO in3, varying different degree of respiratory tract infections, as pneumonia primaryly. Additionally,10HEV positive children were found to be coinfected with other respiratory pathogen from nasopharyngeal aspirate or serum, only one children infected with CVA was a single infection. Overall, the minimum amount of viral load were1.012×104copies/ml, maximum viral load were1.222×109copies/ml, and mean viral load were1.00×109copies/ml.4.Out of the545specimens, at least one respiratory virus was detected in449specimens(82.39%)， The most frenquently detected virus was RSV(37.06%), followed by HRV (23.67%). ADV (21.83%), HBOV (11.01%), HPIV3(10.09%)， HPIV4(6.24%). The incidence between boys and girls virus was not significant difference(χ2=0.000, P=0.995).There was a significant difference observed in the relative prevalence of respiratory viral infction among6-36months than other age groups(x2=42.991. P=0.000). In this study, we had a notly detection rate throughout the study period (>70%), and the majority of viral infections occurred from October to November, each virus presented srong seasonal patterns(HPIV2IFVB, HKU1, NL63except).5.In the study, the mixed infection rate was accounted for41.43%of the total viral agents, the percentage of HBOV (90%) of coinfection was the highest, followed by HPIV4, ADV, HPIV3, HPIV1, HRV. Most of viruses detected positive patients were discharged pneumonia (83.74%). cough (95.32%), fever (58.8%). wheezing (44.32%), catarrh symptoms (27.84%) were the main symptoms of children with viral infection. Of all virus positive patients, prompting positive in35%of children who had conducted CRP check,44%suggested bacterial and virus infections based on sputum culture results, in which Escherichia coli (26.15%), Streptococcus pneumoniae (21.03%), Haemophilus parainfluenzae and Klebsiella pneumoniae (each12.82%), Haemophilus influenzae (8.21%), fungi (4.62%) were the most frequently pathogens.44.71%patients who had been exmined serum antibody prompted at least one virus-IgM positive.Conclusion1. Respiratory virus was the major pathogen of hospitalized children with acute lower respiratory tract infection in Lanzhou. And the most frequently detected virus was RSV, HRV, ADV, HPIV in this year. 2. Five consecutive years of repiratory pathogen detection showed that RSV is the major pathogen, mainly causing lower respiratory tract infections in children, with strong seasonal patterns, peaking in winter and spring, a serious threat to the health of infants under3years old.3. Different from Previous four study years, in the present study.we used nested-PCR to detected HP1V1, HPIV2, HPIV4for the first time and observed HPIV2, HPIV4, also the annual detection rate of HPIVI were higher than the total of last four year studies. Thus, HPIV was the important respiratory tract infection pathogen in Lanzhou.4.The result demonstrated that human enterovirus were circluating in children with acute respiratory tract infection in lanzhou, China. We need do further investigation to definite its roles. |
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