Human metapneumovirus: an emerging respiratory pathogen

Human metapneumovirus (hMPV) is an important emerging respiratory pathogen, previously unreported in the Emergency Medicine literature. It is primarily associated with the clinical syndromes of bronchiolitis and pneumonia. hMPV may predispose to bacterial pneumonia; coinfection with respiratory syncytial virus may lead to increased severity of clinical disease, and complications include asthma and chronic obstructive pulmonary disease exacerbations. Given its high prevalence and potential clinical implications as these patients present to the Emergency Department with initial infection or subsequent complications, a better understanding of hMPV will aid in their care. We report the case of a 13-month old who developed lobar pneumonia 3 weeks after being diagnosed with hMPV. The epidemiology, clinical presentation, complications, and treatment of hMPV are then discussed.     

杭州地区2009甲型H1N1流感重症患儿中人类偏肺病毒感染状况研究

目的了解杭州地区2009甲型H1N1流感（以下简称甲流）重症患儿中人类偏肺病毒（hMPV）的感染状况。方法采集2009年11月至2010年1月确诊为甲流重症患儿的呼吸道样本79份,用传统逆转录聚合酶链反应（RT-PCR）、荧光定量RT-PCR方法检测hMPV及其他呼吸道病毒。选择hMPV阳性样本PCR扩增产物进行核苷酸测序,将所测序列与GenBank比对分析,并绘制基因进化树。结果79份甲流病毒阳性样本中,hMPV及其它呼吸道病毒阳性率20．25％（16,79）,hMPV阳性PCR扩增产物4份,占甲流重症病例的5．06％（4,79）。其中3份hMPV阳性PCR扩增产物核苷酸序列相似性为99．1％～99．5％,与广东省流行株GD．165,泰国株155N及B1代表株高度相似,并且被GenBank收录。结论杭州地区确诊感染的2009甲型H1N1流感重症病例中存在与hMPV共同感染状况,且hMPV均为B1基因型。     

深圳地区儿童呼吸道感染人类偏肺病毒检出及鉴定

目的 应用呼吸道感染常见病毒快速筛查技术检测人类偏肺病毒(human metapneumovirus,hMPV),并对检出的hMPV进行分子生物学鉴定.方法 采用Luminex 100多功能悬浮点阵检测技术和多重PCR技术同时筛查检测呼吸道合胞病毒、流感病毒、人类偏肺病毒等7种病毒、11个亚型.人类偏肺病毒的鉴定采用hMPV核蛋白基因特异性片段PCR扩增、核酸测序,并进行进化树分析.结果 47份临床标本共筛查出病毒19株,检出率40.2%(19/47),其中呼吸道合胞病毒8份、占检出病毒的42.1%(8/19),流感病毒7份(占36.8%),副流感病毒、鼻病毒、柯萨奇病毒、人类偏肺病毒各1份(占5.3%).检出的这例人类偏肺病毒为深圳地区首例,经hMPV核蛋白基因特异性片段核酸序列分析,其与hMPV日本株、北京株、泰国株的同源性＞98%.进化树分析表明深圳株的病毒核蛋白基因与北京株、日本株、泰国株等在同一基因进化簇中.结论 人类偏肺病毒可能是儿童呼吸道感染的主要病毒之一,应引起临床的重视.多功能悬浮点阵和多重PCR技术对病毒感染件疾病的快速筛查具有实用价值,尤其在解决流行病病原学分析方面具有重要意义.     

深圳汕头地区呼吸道感染患儿人偏肺病毒的检出及病原学初步研究

目的：了解人偏肺病毒（hMPV）在深圳汕头地区的感染情况及临床特征。方法收集2010年10月～2012年6月呼吸道感染住院患儿及健康体检儿童鼻咽抽吸物及咽拭子标本共1217例,采用 RT-PCR方法对其进行 hMPV基因筛查,随机选取5份扩增阳性产物进行核酸测序,将所得序列与 GenBank中的序列进行比较和进化树分析。同时,对阳性标本的临床资料进行分析。结果1137份感染患儿标本中检测到hMPV 51份（阳性率4.49％）,2,3,4月为发病高峰,感染患儿主要在3岁以下,占检出率的80.4％,5份阳性标本基因序列与 GenBank 中公布的多株 hMPV N 基因同源性达80.8％～98.4％。进化树分析显示分属于两个不同的基因进化族。51例阳性患儿临床症状均表现为发热、咳嗽、喘息,临床诊断主要为支气管肺炎24例,喘息型肺炎17例,毛细支气管炎9例,上呼吸道感染1例。80例健康体检儿童的呼吸道标本均未检测到 hMPV特异基因片段。结论 hMPV是引起深圳汕头地区3岁以下儿童呼吸道感染的重要病原体之一,并有一定的季节性,其感染无特异的临床表现。流行的 hMPV株存在两种不同基因型。     

徐州地区急性呼吸道感染患者中人偏肺病毒的检测

目的在本实验室建立一种敏感有效的人偏肺病毒(hMPV)的检测方法、了解徐州地区急性呼吸道患者中人偏肺病毒hMPV的感染情况,分析徐州地区hMPV感染人群的流行病学特点及hMPV感染的临床特征,为hMPV的研究提供一些依据。方法在医院呼吸科门诊就诊的急性呼吸道疾病患者(RTI)中采集咽拭标本,用逆转录聚合酶链反应(RT-PCR)检测hMPV的核蛋白N基因,并对扩增产物进行基因序列的测定后将之与GemBank的hMPV的全序列进行比对。结果2005年1月至2005年3月的75份标本用RT-PCR的方法检测后,确定有12份标本为N基因阳性,检出率为16.0%,扩增产物均经基因序列分析比对。结论徐州地区的急性呼吸系统疾病中存在hMPV感染,且在徐州地区急性呼吸系统疾病中约有16.0%的患者是由hMPV感染引起,其中6岁以下儿童占50%,这些hMPV感染患者的临床症状主要表现为:高烧、咳嗽。     

Identification and evaluation of a highly effective fusion inhibitor for human metapneumovirus

Human metapneumovirus (hMPV) can cause acute upper and lower respiratory tract infections that are particularly severe in young children, elderly subjects, and immunocompromised patients. To date, no treatments or vaccines are available for hMPV infections. Our objective was to assess the inhibitory potential of several peptides derived from the heptad repeat A and B (HRA and HRB) domains of the hMPV fusion protein. Nine candidate peptides were expressed in Escherichia coli or obtained synthetically and tested in vitro and in an animal model. Excellent in vitro inhibition of an hMPV strain of the A1 subgroup was obtained with five peptides, with 50% inhibitory concentrations ranging from 1.4 nM to 3.3 microM. One peptide, HRA2, displayed very potent activity against all four hMPV subgroups. It was also moderately active against human respiratory syncytial virus (strain A2) but displayed no activity against human parainfluenza virus type 3. BALB/c mice that received the HRA2 peptide and a lethal hMPV intranasal challenge simultaneously were completely protected from clinical symptoms and mortality. On day 5 postinfection, HRA2-treated mice had undetectable lung viral loads which were significantly less than those of untreated mice (3 x 10(4) 50% tissue culture infective doses/lung). Pulmonary inflammation, levels of proinflammatory cytokines/chemokines (RANTES, gamma interferon, and monocyte chemoattractant protein 1) and airway obstruction were also significantly decreased in HRA2-treated mice. The results of this study demonstrate that potent antivirals can be derived from the hMPV fusion protein HR domains. Moreover, hMPV, compared to other paramyxoviruses and to the human immunodeficiency virus, seems to be more susceptible to HRA- than HRB-derived peptides.     

急性呼吸道感染患儿的病原学研究

目的探讨苏州地区7岁以下儿童急性呼吸道感染（ARTI）的病原学分布。方法无菌负压吸引法采集1668侧7岁以下ARTI住院患儿新鲜痰液,细菌培养检测细菌,直接免疫荧光法检测7种呼吸道病毒,逆转录聚合酶链反应（RrPCR）法检测人类偏肺病毒（hMPV）N基因,酶联免疫吸附试验（ELISA）法检测血清肺炎支原体（MP）抗体。结果1668例患儿中,病原检测阳性1107例（66．4％）,其中单纯病毒感染359例（21．5％）,单纯细菌感染271例（16．3％）,单纯肺炎支原体感染222例（13．3％）,混合感染255例（15．3％）。病毒以呼吸道合胞病毒（RSV）为主（19．2％）,人类偏肺病毒（hMPV）次之（12．0％）;细菌则以肺炎链球菌为主（12．0％）,其次为流感嗜血杆菌（3．8％）。结论①本地区7岁以下ARTI儿童最常见病原是病毒,其次是细菌、支原体。②RSV是本地区冬春季低年龄婴幼儿ARTI的主要病原。流感病毒、副流感病毒感染无流行迹象。本地区hMPV在2008年3～5月有一流行高峰。肺炎链球菌、流感嗜血杆菌是主要的细菌病原。MP感染多见于1岁以上儿童。混合感染则多见于3岁以下儿童。     

Genotype variability and clinical features of human metapneumovirus isolated from Korean children, 2007 to 2010

This study was undertaken to determine the genotype variability of human metapneumovirus (hMPV) and its circulation pattern over a 3.5-year period, and to evaluate its clinical characteristics in Korean children. We investigated 4599 pediatric patients who were referred for a routine respiratory virus test by RT-PCR. hMPV genotype analyses were performed using a nested PCR-restriction fragment length polymorphism assay. Clinical and laboratory data obtained from medical records were reviewed retrospectively. Of the 4599 samples tested, 325 (7.1%) were positive for hMPV, and the co-infection rate among these 325 was 16%. Nested PCR-restriction fragment length polymorphism analysis clearly identified four of the five hMPV genotypes (A2a, A2b, B1, and B2) in 97.8%. The predominant genotype of hMPV changed over the 3.5-year study period from genotype A2a to B2 and then back to A2a. The most common genotype was A2a (214/325, 65.8%). Evidence of recurrent infection was obtained in one child only. Lymphocytosis was more frequent in children with a co-infection, but sputum production was less frequent than in children with a single infection. In genotype A2a hMPV-infected children, sneezing and neutrophilia were more frequent than in genotype B1 or B2 hMPV-infected children. This study broadens knowledge regarding the prevalence, the seasonal incidence, the occurrences of co-infection and re-infection, and the genotype diversity of hMPV in Korea.     

人偏肺病毒基因型双重逆转录PCR检测方法的建立

目的 建立一种鉴别不同基因型hMPV的RT-PCR方法.方法 根据不同基因型的hMPV G蛋白基因序列设计合成A、B基因型的特异性引物,在一次双重PCR反应中根据扩增产物大小鉴别不同基因型.用该方法鉴别37份hMPV阳性的临床标本的基因型.结果 用hMPV G蛋白编码基因的分型引物进行PCR反应,对已知的hMPV阳性标本直接进行分型得到的扩增产物大小易于区分;对常见的呼吸道病毒无非特异扩增,显示引物特异性良好.对37份临床标本进行基因分型结果显示,20份A基因型分型结果与M基因测序分型结果一致,17份经M基因测序分型为B基因型的阳性标本中有14份与M基因测序分型结果一致,3份未得到扩增产物从而不能分型,总符合率为91.9%[(20+14)/37].结论 成功建立了一种可以鉴别不同基因型的hMPV的RT-PCR方法.     

Effect of ribavirin and glucocorticoid treatment in a mouse model of human metapneumovirus infection

Human metapneumovirus (hMPV)-infected BALB/c mice were treated with ribavirin (40 mg/kg of body weight twice a day intraperitoneally), corticosterone (0.2 mg/ml in water), or both modalities. Ribavirin significantly decreased both hMPV replication in lungs (by 5 log10) and global pulmonary inflammation on day 5 postinfection, whereas glucocorticoids reduced only alveolar and interstitial inflammation, compared to controls.     

GeXP多重RT-PCR技术在呼吸道病毒检测中的应用

目的 应用GeXP多重基因表达遗传分析系统多重RT-PCR技术检测急性呼吸道感染儿童呼吸道样本中的呼吸道病毒并探讨其在儿童呼吸道感染病毒检测中的价值。方法 回顾性检测2010年7月～2012年6月期间因疑似急性呼吸道感染就诊的1 800名儿科患者的呼吸道样本,应用GeXP多重基因表达遗传分析系统多重RT-PCR技术对呼吸道合胞病毒、鼻病毒等多种呼吸道病毒进行检测。采用SPSS 13.0统计软件进行统计学分析。结果 GeXP多重RT-PCR方法检测到样本中的10种呼吸道病毒。样本中共有67.33%(1 212/1 800)的样本至少有一种病毒检测结果为阳性。这1 212份病毒阳性标本中,人类鼻病毒(HRV)阳性最多,为375份,阳性率20.83%; 其次为呼吸道合胞病毒(RSV)249份,阳性率13.83%; 其他依次为人类腺病毒(HADV)、人类副流感病毒3(HPIV-3)、人类博卡病毒(HBoV)、甲型流感(InfA)、人类副流感病毒4(HPIV-4)、流感C(InfC)、人类偏肺病毒(hMPV)和乙型流感病毒(Inf B); 阳性率分别为8.89%,6.5%,5.3%,5.3%,3.3%,1.5%,1.11%和0.67%。不同性别间患儿呼吸道病毒阳性率差异无统计学意义(P>0.05)。研究中观察到13.5%(243/1 800)的病例同时感染两种或两种以上的病毒,其中两种病毒的混合感染为210例(11.67%),3种病毒混合感染为33例(1.83%)。呼吸道病毒的感染率存在季节差异,RSV大多在春季和冬季流行,HBoV,hMPV,InfA,Inf B和 HPIV-3大多是在春季流行,而HADV和HPIV-4主要在夏季流行,Inf C大多是在秋季流行。结论 GeXP分析系统多重RT-PCR方法是一个快速、高通量、高灵敏度且特异度强的检测分析方法,可用于急性呼吸道感染临床分子诊断和流行病学研究。     

The prophylactic administration of a monoclonal antibody against human metapneumovirus attenuates viral disease and airways hyperresponsiveness in mice

BACKGROUND: Human metapneumovirus (hMPV) is one of the most frequent causes of respiratory tract infections in children. Our objective was to assess the prophylactic benefit of a monoclonal antibody (mAb) against the hMPV fusion protein in a murine model. METHODS: BALB/c mice received one intramuscular injection of either 5 or 10 mg/kg of mAb 338 (MedImmune, Inc.) and were infected intranasally 24 h later with 1x10(8) TCID50 (50% tissue culture infectious dose) of hMPV. On days 5 and 42 post-infection, lung samples were collected for determination of viral titres and for histopathological studies. Pulmonary function was characterized by plethysmography. RESULTS: Mean lung viral titres were significantly lower in mice treated with 5 or 10 mg/kg of mAb 338 compared with infected controls on day 5 (283, 45.6 and 1.49x10(5) TCID50/g, respectively; P<0.05). Similarly, lung viral RNA copies were significantly reduced in treated mice on day 42 (292, 101 and 607 copies per 0.01 g of lungs for mice that received 5 mg/kg, 10 mg/kg or no mAb, respectively; P<0.05). Histopathological changes characterized by important alveolar and interstitial inflammation were less severe in treated mice on days 5 and 42 compared with control. Airways obstruction was also significantly reduced in both treated groups on days 5 and 42, but development of hyperresponsiveness following the acute phase of infection was only significantly reduced in 10 mg/kg treated mice. CONCLUSIONS: Prophylactic administration of mAb 338 attenuates acute and late consequences of hMPV disease in this mouse model.     

Efficacy of Oral Ribavirin in Hematologic Disease Patients with Paramyxovirus Infection: Analytic Strategy Using Propensity Scores

Few antiviral agents are available for treating paramyxovirus infections, such as those involving respiratory syncytial virus (RSV), parainfluenza virus (PIV), and human metapneumovirus (hMPV). We evaluated the effect of oral ribavirin on clinical outcomes of paramyxovirus infections in patients with hematological diseases. All adult patients with paramyxovirus were retrospectively reviewed over a 2-year period. Patients who received oral ribavirin were compared to those who received supportive care without ribavirin therapy. A propensity-matched case-control study and a logistic regression model with inverse probability of treatment weighting (IPTW) were performed to reduce the effect of selection bias in assignment for oral ribavirin therapy. A total of 145 patients, including 64 (44%) with PIV, 60 (41%) with RSV, and 21 (15%) with hMPV, were analyzed. Of these 145 patients, 114 (78%) received oral ribavirin and the remaining 31 (21%) constituted the nonribavirin group. Thirty-day mortality and underlying respiratory death rates were 31% (35/114) and 12% (14/114), respectively, for the oral ribavirin group versus 19% (6/31) and 16% (5/31), respectively, for the nonribavirin group (P = 0.21 and P = 0.56). In the case-control study, the 30-day mortality rate in the ribavirin group was 24% (5/21) versus 19% (4/21) in the nonribavirin group (P = 0.71). In addition, the logistic regression model with IPTW revealed no significant difference in 30-day mortality (adjusted hazard ratio of 1.3; 95% confidence interval [95% CI] of 0.3 to 5.8) between the two groups. Steroid use (adjusted odds ratio, 5.67; P = 0.01) and upper respiratory tract infection (adjusted odds ratio, 0.07; P = 0.001) was independently associated with mortality. Our data suggest that oral ribavirin therapy may not improve clinical outcomes in hematologic disease patients infected with paramyxovirus.     

Surveillance of viral respiratory tract infections over a one year period in mainly hospitalized Austrian infants and children by a rapid enzyme-linked immunosorbent assay diagnosis

In order to obtain more information on viral respiratory tract infections in Austrian infants and children, nasopharyngeal secretions from 1432 infants and children, collected from October 1984 to October 1985, were screened for the presence of respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus type 1, 2, and 3, and influenza viruses type A and B, by enzyme-linked immunosorbent assay (ELISA). The results obtained were analyzed with respect to incidence, seasonal distribution and clinical syndromes associated with the different viral pathogens investigated and also with the practicability of ELISA diagnostics over long distances. A viral etiology of acute respiratory tract infection was confirmed in 372 (26%) infants. RSV was detected in 286 (20%) of the nasal secretions and was thus the most frequently encountered agent. RSV infections occurred mainly in the winter months and were often associated with bronchitis, bronchiolitis, and pneumonia. Only sporadic infections were found with one of the other viruses investigated.