| ObjectiveTo understand the molecular epidemiology characteristics of respiratory viruses in children with acute respiratory infections (ARTI) in Nanjing with the method with RT-PCR or nested-PCR to detected thirteen common respiratory viruses from nasopharyngeal aspirates or nasopharyngeal swabs which were collected from Nanjing Children’s Hospital. To investigate the potential pathogens of the22special specimens which were collected from children with severe pneumonia, and the22patients had the same symptoms (hyperpyrexia and wheezing), and did not respond to antibiotics, we conducted the viral pathogen detection.Subjects and methods1.644respiratory samples which contain nasopharyngeal aspirates and nasopharyngeal swabs were respectively collected from381inpatients and263outpatients with acute respiratory tract infections in Nanjing Children’s Hospital from August2010to July2011.2. The collected samples were stored in DMEM with BSA(Bull Serum Albumin), glutamine and PS in it.They were transported to the laboratory at the National Institute for Viral Disease Control and Prevention, China Centre for Disease Control, and stored at-80℃until further processing.3. Nested-PCR was used to detected ADV, HBoV, PIV1, PIV2and PIV4. Other respiratory viruses (RSV, HRV, IFVA, IFVB, PIV3, HMPV, HCoV-HKU1and NL63) were identified by RT-PCR.4.22nasopharyngeal aspirates from Hunan People’s Hospital were conducted to detect ADV, HBoV, HMPV, RSV, HRV, PIV1, PIV3, IFVA, IFVB, NL63and HKU1. The complete genome of the two ADV7isolated (h5and h6) were sequenced.Result1. In this study, we used a new method (nested-PCR) to detect PIV1, PIV2and PIV4, and their detetion rates were respectively6.52%(42/644),1.40%(9/644) and5.90%(38/644). The detection rates of PIV1and PIV2were higher than those of the previous results in Nanjing and Lanzhou in the same laboratory.2. Adenoviruses were detected in171patients out of644(26.55%) children. The types of the adenoviruses were as follows:120(70.18%,120/171) for AD V3,16(9.36%,16/171) for ADV7,12(7.02%,12/171) for ADV1,10(5.85%,10/171) for ADV2,6(3.51%,6/171) for ADV5,3(1.75%,3/171) for ADV6,3(1.75%,3/171) for ADV57,1(0.58%,1/171) for ADV41. ADV infection could occur in any season. There was a higher possibility of ADV infection from April to July in2011. Most cases (96.49%) were younger than7years old.99of the171ADV-positive children (57.89%) were co-infected with other respiratory viruses. Respiratory syscytial virus (RSV) and human rhinovirus (HRV) were the most common additional viruses. Lower respiratory tract infections were the most frequent clinical diagnoses, in which there were52pneumonias (30.4%).3. Of a total of644NPAs collected from August2010to July2011,487(75.62%) were positive for at least one respiratory virus. The most common identified virus was RSV whose detection rate was27.17%(175/644), followed by ADV26.55%(171/644), HRV15.68%(101/644), PIV313.51%(87/644), HBoV6.68%(43/644), PIV16.52%(42/644), PIV45.90%(38/644), HMPV4.97%(32/644), IFVB2.95%(19/644), NL631.86%(12/644), PIV2and HKU11.40%(9/644), IFVA1.24%(8/644).13common respiratory viruses were all detected in this study. Among the487positive samples, the boys were352and the girls were135; there was no statistical significance between the two gender rates. The minimal age of the child was0.004month, the maximum was151months, the media age was9months and the average age was18.3months. The frequency of virus detection of the children less than3yeas (78.24%) was higher than that of more than3years (64.17%), and this difference was significant (χ2=10.496, P=0.001).4. Of the22special respiratory specimens from the department of Hunan People’s Hospital, the most common detected virus was ADV (n=19), followed by RSV (n=7), PIV3(n=3), HBoV (n=4), HRV (n=2), PIV1(n=2) and HKU1(n=1). HMPV, IFVA, IFVB and NL63were not identified. The complete genome of the two ADV7isolated (h5and h6) were sequenced, and the two stains exhibited99%nucleotide identity to other ADV7in GenBank.Conclusion1. A viral etiology could be determined in487of the644(75.62%) in the respiratory samples which were collected from children with acute respiratory tract infections in Nanjing area from2010to2011. This result indicates viral etiology was one of the most common causes of respiratory tract infections of children in Nanjing, especially RSV, ADV and HRV were the first three viral agents of respiratory diseases of children.2. In our study, the detection of ADV was in the second place. ADV infections could accur throughout the year, and the predominant serotype was ADV3in Nanjing area between2010and2011. And we identified3HAdV-57which belong to species C. HAdV-57was a recently identified novel serotype of HAdV-C. It was a recombinant virus.The emergence of the novel ADV serotypes indicated that we should closely monitor the serotypes and combinations of ADV in the future study.3. Compared to previous results of Nanjing and Lanzhou in the same laboratory, we first detected PIV1, PIV2and PIV4by nested-PCR which was different from the previous method in the same laboratory. The detection rates of the three PIVs respectively were6.52%,1.40%and5.90%. The phenomenon showed that PIVs were also very common viral antigens in children with respiratory tract infections and should be continuously monitored.4. ADV7was the most important etiology of the22special specimens which were collected from children with severe pneumonia, and the22patients had the same symptoms (hyperpyrexia and wheezing), and did not respond to antibiotics. The complete genome of ADV7isolated (h5and h6) were sequenced and phylogenetic analysis showed that the genetic relationship between the two stains of ADV7and other two ADV7stains (JN860677and AY601634)was the closest. |
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