兰州地区冠状病毒HKU1在儿童急性呼吸道感染的研究

Molecular epidemiological and clinical features of coronavirus HKU1 in children with acute respiratory tract infection in Lanzhou

目的 了解兰州地区冠状病毒HKU1（Human CoV-HKU1）在儿童急性呼吸道感染中的分子流行情况和临床特点.方法 采用逆转录聚合酶链反应（RT-PCR）方法,对2007年11月～2008年10月兰州大学第一医院301例急性呼吸道感染患儿的鼻咽抽吸物进行冠状病毒HKU1基因检测,阳性产物经克隆、测序、同源性和进化分析,阳性标本同时检测呼吸道合胞病毒、腺病毒、鼻病毒、流感病毒、副流感病毒、偏肺病毒和冠状病毒NL63.结果 301份标本中共检出冠状病毒HKU1阳性扩增产物15份,检出率为5.0%,氨基酸同源性在90.7%～99.3%之间,与标准株HKU1-B（DQ415911）属于同一进化簇.有11例存在混合感染,时间分布在11月至次年4月.15例阳性患儿年龄10个月（15 d～12岁）,主要诊断包括上呼吸道感染,支气管炎,支气管肺炎,肺炎,细支气管炎;临床表现包括发热、咳嗽、咯痰、腹泻、呕吐、咽充血、湿啰音、哮鸣音.无死亡病例.有6例患有基础性疾病.结论 在兰州地区急性呼吸道感染患儿中检出冠状病毒HKU1,基因型为B型.临床症状及诊断无特异性.

Objective Human coronavirus （CoV）-HKU1 （HCoV-HKU1） was first isolated by Woo et al in Hong Kong. Several successive reports confirmed retrospectively that this new human coronavirus was circulating in different countries worldwide. However, the impact and the role of the emerging HCoV-HKU1 were not defined in children with ARTI. The objective of this study was to investigate the molecular epidemiology and clinical characteristics of HCoV-HKU1 infection in children with ARTI in Lanzhou, China. Method Nasopharyngeal aspiration （NPA） samples were collected from 301 children with ARTI at the First Hospital of Lanzhou University, Gansu Province, China, between November 2007 and October 2008. Demographic data and clinical findings of these children were collected at the same time. The informed consent was obtained from their parents. This study protocol was approved by the hospital ethics committee. The reverse transcription polymerase chain reaction （RT-PCR） was employed to screen HCoV-HKU1. Furthermore, other common respiratory viruses were screened in HCoV-HKU1 positive samples. All PCR positive products were sequenced, and phylogenetic analysis was conducted. Result The overall frequency of HCoV-HKU1 infection was 5.0% （ 15/301 ）. The HCoV-HKU1 pol gene sequences shared a 95.8% -99.6% nucleotide identity with the human coronavirus-HKU1 strain, whereas the amino acid identity was 90.7% - 99.3%. The phylogenetic analysis revealed that the HCoV-HKU1 strain pol gene clustered with the HCoV-HKU1 strain N15 genotype B （no. DQ415911 ）; 11 of 15 HCoV-HKU1 positive sample tested were mixed-infection. HCoV-HKU1 was detected only from November to April. Positive specimens peaked in November. Children with HCoV-HKU1 infection varied in age from 15 day to 12-years （median age, 10 months）. The clinical diagnoses of HCoV-HKU1 positive patients included those with AURI and LURI. The clinical presentations of HCoV-HKU1 positive children included fever, cough, sputum production, diarrhea, vomiting; pharynx engorgement, crackles, and wheezing. The mean hospital stay of the 14 patients was 9.9 days. Six of 15 HCoV-HKU1 positive patients had an underlying illness, and they were all inpatients （hospital stay, mean, 11.2 days）. There was no statistically significant difference in the detection rate between the two groups with and without underlying illnesses. Conclusion Human CoV-HKU1 infection exists in children with respiratory tract infections in Lanzhou region. A single HCoV-HKU1genotype B was circulating locally. The symptoms and clinical diagnoses of those infected with HCoV-HKU1had no specificity as compared with patients with other common respiratory viruses infection.