从北京地区急性呼吸道感染患儿标本中检测到新型冠状病毒NL63基因

目的了解北京地区婴幼儿急性呼吸道感染是否与一种新发现的冠状病毒——HCoV-NL63相关。方法选取2003年12月—2004年3月,从首都儿科研究所附属儿童医院收集的245份因急性呼吸道感染就诊的门诊患儿的咽拭子标本以及住院患儿的鼻咽洗液标本,进行HCoV-NL63的筛查。这些标本已经过间接免疫荧光法和病毒分离检测,常见的七种呼吸道病毒（包括RSV,甲、乙型流感病毒,Ⅰ、Ⅱ、Ⅲ型副流感病毒和腺病毒）检测均为阴性;同时还经逆转录-聚合酶链反应（RT-PCR）方法检测人偏肺病毒（hMPV）也为阴性。首先用位于HCoV—NL631b基因的两对引物用巢式PCR方法进行筛查,阳性者再用位于HCoV-NL63 1a基因的两对引物扩增进行复核。对用HCoV—NL63 1a基因扩增的长片段产物进行测序并与GenBank中相关序列进行比较分析。结果用HCoV-NL63 1b基因的引物经巢式PCR方法从245份标本中检测到3份阳性标本,阳性率为1．2％。3份阳性标本用HCoV-NL63 1a基因的两对引物经巢式PCR方法进行复核均得到阳性结果,这3份标本均取自住院患儿,患儿年龄分别为4个月、1岁和1岁5个月,临床诊断分别为毛细支气管炎、喉炎和支气管炎,男女比例为2：1。对其中基因扩增产量较高的BJ3140和BJ3787的1a基因长片段扩增产物（838bp）进行序列测定和分析的结果显示,这两株HCoV-NL63与GenBank公布的不同地区的HCoV—NL63的1a基因序列同源性最高,达到98％～99％。基于部分1a基因序列的系统进化分析显示,BJ3140和BJ3787属于HCoV-NL63的第一簇（group 1）。结论结果提示北京地区部分婴幼儿的急性呼吸道感染与HCoV-NL63相关。     

Respiratory morbidity of hospitalized children with Trisomy 21

OBJECTIVE: To review the respiratory morbidity in children with Trisomy 21 admitted to a teaching hospital. METHODOLOGY: A retrospective chart review of 232 admissions to John Hunter Children's Hospital during a 6.5-year period (1991-98). The primary outcome measures included: (i) primary reason for admission, (ii) concomitant respiratory pathology, (iii) admission to the Intensive Care Unit (ICU), (iv) length of stay and (v) costs of admission. RESULTS: Fifty-four per cent of admissions were primarily for respiratory tract pathology, dominated by pneumonia, bronchiolitis and croup. Admission to the ICU was required for 10% of admissions, most commonly for pneumonia (10/23). Congenital heart disease (CHD) was present in 33% of patients. The median length of stay and cost of admission for a child with Trisomy 21 (without CHD) with common respiratory conditions such as bronchiolitis, asthma or pneumonia was two to three times greater than in patients without Trisomy 21. CONCLUSION: Lower respiratory pathology is most common cause for acute hospital admission in children with Trisomy 21. The presence of CHD did not influence admission rates to hospital. However, patients with CHD had longer lengths of stay, appeared to have more severe illness, were more likely to require admission to an ICU and were more likely to require ventilatory support.     

��������С�������º������ϰ���������Ⱦ���ٴ��о�

目的 了解昆明地区呼吸道合胞病毒(RSV)在小儿急性下呼吸道感染中的发生率和临床特征.方法 对昆明市儿童医院2006年4月至2007年4月临床诊断为急性下呼吸道感染的住院患儿1112例行痰间接免役荧光法检测呼吸道合胞病毒抗原.结果 1112例标本中,阳性276例,阳性率24.82%,其中男190例(17.09%),女86例(7.73%),男女发病比例为2.21∶1.全年均可检出RSV,发生率最高的是10～12月份(30.15%),最低的是4～6月份(10.93%).RSV感染多见于3岁以下,尤以6个月以下患儿感染率最高(36.22%).结论 呼吸道合胞病毒是引起昆明地区小儿急性下呼吸道感染的主要病原,特别是婴幼儿感染率最高.     

先天性心脏病并下呼吸道感染患儿病原学及细菌耐药性分析

目的了解先天性心脏病(CHD)并下呼吸道感染的病原学组成及细菌耐药情况,以指导临床治疗。方法回顾性分析2006年8月-2011年3月本科收治的156例CHD并下呼吸道感染患儿的鼻咽分泌物病毒、细菌检测结果和药敏试验报告。采用直接免疫荧光法检测呼吸道合胞病毒、副流感病毒3等7种常见呼吸道病毒,K-B法进行细菌药敏试验。结果 156例CHD并下呼吸道感染患儿中,病毒感染29例(18.6%),以呼吸道合胞病毒(14.7%)为主;细菌感染97例(62.2%),以革兰阴性杆菌为主,前3位细菌依次为肺炎克雷伯菌(19.9%)、大肠埃希菌(17.9%)和肺炎链球菌(7.7%);检出真菌(白色假丝酵母菌)7例(4.5%);混合感染36例(23.1%)。肺炎克雷伯菌和大肠埃希菌产超广谱β内酰胺酶(ESBLs)阳性菌株合计检出率为23.7%;肺炎克雷伯菌和大肠埃希菌对氨苄西林的耐药率分别达100%和96.4%,对头孢类抗生素耐药率达50.0%以上,而对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦有效,对亚胺培南高度敏感;肺炎链球菌对氨苄西林、红霉素耐药率达60.0%以上,对头孢类抗生素有效,对亚胺培南、万古霉素高度敏感。结论 CHD并下呼吸道感染患儿的主要病原为细菌,以革兰阴性杆菌为主,混合感染多见,并检出有真菌,主要细菌的耐药性及革兰阴性杆菌产ESBLs率均较高。应加强CHD下呼吸道感染病原学检测,以指导合理用药,减少耐药菌株的产生和真菌感染的发生。     

武汉地区12125例呼吸道感染患儿非细菌病原体IgM抗体检测结果分析

目的检测武汉地区住院呼吸道感染患儿非细菌病原体IgM抗体,为临床诊疗提供依据。方法取诊断为呼吸道感染的12 125例住院患儿的血清,采用间接免疫荧光法检测9种呼吸道感染非细菌病原体的IgM抗体。结果 3 597份标本(29.7%)非细菌病原体IgM抗体检测阳性,其中肺炎支原体(MP)的阳性率最高为21.6%,其次为腺病毒(ADV)和乙型流感病毒(Flu B),阳性率最低为肺炎衣原体(CP)和Q热立克次体(COX);混合感染563例,其中主要是2种病原体的混合感染。各年龄组(0～30 d、～6个月、～1岁、～3岁、～9岁)的总检出率分别为30.4%、18.7%、35.4%、68.4%、55.2%,各组间差异有统计学意义(χ2=89.5,P<0.05)。冬季非细菌病原体检出率最高(53.4%),秋季最低(24.9%),差异有统计学意义(χ2=760.3,P<0.05)。结论武汉地区呼吸道感染患儿的非细菌病原体主要是MP、ADV和Flu B;MP和其他非细菌病原体的混合感染比较普遍;1～3岁幼儿感染率较高;冬季更易感。     

下呼吸道感染患儿支气管肺泡灌洗液的病原学研究

目的 研究下呼吸道感染患儿病原体特点,为临床医生合理使用抗生素提供依据。方法 选取2017年1月至2018年6月因下呼吸道感染住院且接受纤维支气管镜治疗的108例患儿为研究对象,收集其支气管肺泡灌洗液,通过多重实时荧光PCR检测其病原体。结果 在108例患儿中,检测出病原体85例（78.7%）,其中单一病原体感染检出52例（48.1%）,多重病原体感染检出33例（30.6%）。肺炎支原体检出率最高,共检出38例（35.2%）,其中36~ < 72月龄患儿检出率最高;其次为肺炎链球菌及流感嗜血杆菌,各检出29例（26.9%）,其中肺炎链球菌主要集中于24月龄以下患儿。检出率较低的为鲍曼不动杆菌、白色念珠菌及肺炎克雷伯杆菌,各检出3例（2.8%）。在31例支气管肺炎患儿中,流感嗜血杆菌检出率最高（9例,29%）。在34例大叶性肺炎患儿中,肺炎支原体检出率最高（22例,65%）。在22例支气管异物合并支气管肺炎患儿中,肺炎链球菌检出率最高（10例,45%）。结论 在下呼吸道感染患儿中,肺炎支原体检出率最高,其次为肺炎链球菌及流感嗜血杆菌。不同年龄、不同类型下呼吸道感染患儿的病原体检出率存在差异。     

Frequent detection of viral coinfection in children hospitalized with acute respiratory tract infection using a real-time polymerase chain reaction

BACKGROUND: Respiratory viruses are the main cause of acute respiratory tract infection (ARI) in children. Real-time polymerase chain reaction (PCR) technology is highly practicable for the rapid detection of viral pathogens. The simultaneous detection of a broad spectrum of viruses enables the diagnosis and evaluation of viral coinfection in ARI. METHODS: A 1-step real-time PCR was developed for the detection of 12 respiratory viruses (10 RNA and 2 DNA viruses) in clinical samples. Clinical samples from 254 children admitted to the Departments of Pediatrics with ARI during a 10-month period were tested. RESULTS: Respiratory syncytial virus (RSV) was the most frequently detected pathogen in 112 samples (44.1%), followed by human bocavirus (hBoV) in 49 (19.3%), and rhinovirus in 17 samples (6.7%). Viral coinfection was detected in 41 (16.1%) samples with RSV and hBoV being the most dominating combination (27 cases, 10.6%). Viral coinfection was found in 10 cases (17%) of children with bronchitis (n = 58) and in 7 cases (23%) of bronchiolitis (n = 30). In patients with pneumonia (n = 51), 17 cases (33%) were positive for 2 or more viral pathogens. CONCLUSIONS: Simultaneous testing of respiratory viruses by real-time PCR is a suitable tool for the detection of viral coinfections. In children hospitalized because of respiratory infection viral coinfection is frequently detected with RSV and hBoV being a common combination.     

WU多瘤病毒在急性呼吸道感染儿童中的检出及初步临床研究

目的 了解WU多瘤病毒(WU polyomaviros,WUPyV)在小儿呼吸道感染中的检出情况及感染患儿的临床特点.方法 应用PCR技术,对2008年7月至2009年6月广东省汕头大学医学院第二附属医院儿科急性呼吸道感染住院患儿的呼吸道鼻咽抽取液及健康体检儿童呼吸道鼻咽抽取液进行WUPyV核酸检测,阳性结果 再进一步基因测序,并分析阳性患儿的临床资料.结果 771例患儿中WUPyV阳性15例,阳性率1.95%,其中单纯WUPyV感染9例(60%),合并其他病毒感染的有6例(40%).82例健康体检儿童WUPyV的PCR检查均阴性.所有WUPyV阳性患儿年龄均≤4岁,最小2个月,最大48个月,平均年龄18.8个月;男: 女=1.5:1,临床诊断主要是:支气管肺炎、细支气管炎、上呼吸道感染、支气管炎,其中1例重症患儿合并病毒性脑炎.结论 WUPyV可能是呼吸道感染病原体,其主要感染对象是婴幼儿,主要症状是咳嗽和喘息,个别有重症表现.     

7岁以下儿童急性下呼吸道感染病原学研究

目的 探讨苏州地区7岁以下儿童急性下呼吸道感染的痛原学分布.方法 对2007年10月至2008年3月间苏州大学附属儿童医院呼吸科住院患儿中7岁以下急性下呼吸道感染住院患儿810例,采用无菌负压吸引法采集新鲜痰液,进行细茵培养,直接免疫荧光法检测病毒,酶联免疫吸附试验(ELISA)法检测血清支原体、衣原体抗体.结果 810例患儿中556例病原栓测阳性(68.6%),单纯病毒感染181例(22.3%),单纯细菌感染124例(15.3%),单纯支原体感染72例(8.9%),单纯衣原体感染10例(1.2%),混合感染169例(20.9%).病毒以呼吸道合胞病毒为主(35.8%),细菌则以肺炎链球菌为主(13.8%),其次为流感嗜血杆菌(4.6%).结论 苏州地区7岁以下儿童急性下呼吸道感染最常见痛原是病毒,其次是细菌、支原体、衣原体.支原体感染多见于1岁以上儿童,混合感染则多见于3岁以下儿童.     

Respiratory viruses in acute respiratory tract infections in Western India

Objective  To study the circulation pattern of respiratory viruses in out patients department (OPD) and hospitalized children with acute respiratory tract infection. Methods  Nasopharyngeal aspirates were collected from 385 children with acute respiratory tract infections attending the OPD (n=199, 51.7%) and admitted to pediatric ward (n=186, 43.2%). Specimens were screened for seven respiratory viruses by immunofluoresence test (IFT) using Respiratory panel 1 screening and identification kit. Results  Viral antigens were detected in 57 (28.6%) and 86 (46.2%) patients from OPD and admitted cases respectively, giving an overall positivity of 143 (37.1%) for respiratory viruses. Of the six respiratory viruses, the most common was respiratory syncytial virus (RSV) in 100 (26%) patients, followed by influenza viruses in 21 (5.4%), parainfluenza in 8 (2.07%), adenovirus in 3 (0.8%). One patient had mixed infection of RSV and adenovirus. RSV was most frequently detected in the hospitalized children (39.8%). Conclusion  RSV appeared to be the most common respiratory viral infection in the age group 0–1 year causing hospitalization.     

儿科病房常见病与儿童疾病综合管理关系的探讨

目的　探讨 5岁以内儿科住院病例常见病与儿童疾病综合管理 (IMCI)的关系。方法　分析该院1995～ 2 0 0 0年住院的 1周至 5岁的肺炎、腹泻病、营养不良、麻疹和疟疾 346 8例次。结果　①肺炎和腹泻病分别占 5种疾病的 6 2 .1%和 34.1% ;5种疾病并发症中营养不良最常见 (6 2 .1% )。② 1周至 2月住院患儿中前 3位死因依次为 :肺炎 (32 .1% )、晚期新生儿高胆红素血症 (2 5 .0 % )和维生素K缺乏症 (2 3.2 % ) ,常见病则以晚期新生儿高胆红素血症最多见 (43.8% ) ;2月至 5岁住院患儿中前 3位死因依次为肺炎 (2 5 .4 % )、颅内感染 (2 3.6 % )和败血症 (10 .9% ) ,常见病则以肺炎 (2 0 .2 % )、急性上呼吸道炎 (16 .8% )和腹泻病 (10 .5 % )多见。③ 5种疾病患儿占儿内科和传染科同期住院人数的 2 1.0 %和 2 .1% ,儿内科住院病例占同期门、急诊人数的 1.2 %。结论　除肺炎、腹泻病和营养不良外 ,该地区的IMCI中 ,1周至 2月的患儿应包括晚期新生儿高胆红素血症和维生素K缺乏症 ,2月至 5岁患儿应包括急性上呼吸道炎和颅内感染。应加强门、急诊工作和儿内科与传染科的合作     

Nosocomial infections in black South African children

Nosocomial infections in infants and children were prospectively studied in the general wards of a hospital serving a developing community. Of 1350 admissions in 5 months, 193 (14.3%) developed 302 infections (22.4/100 admissions). The major risk factors were malnutrition, age less than 2 years and prolonged hospitalization. The most common sites of infection were the lower respiratory and gastrointestinal tracts. The most frequently isolated organisms were Staphylococcus aureus and Klebsiella species and the site of most frequent isolation was the lower respiratory tract for which the method most commonly used was endotracheal aspiration. Seventy percent of isolates were resistant in vitro to conventional antibiotics. Thirty-one percent of infections developed while the patient was awaiting a diagnostic procedure or waiting to be sent home. During the study period 60 patients (4.4% of admissions) were admitted with a nosocomial infection acquired elsewhere (31 at this hospital and 29 from other hospitals). Measles and its complications accounted for 28 of these cases and 7 deaths. This study provides information on nosocomial infections in children from a developing community.     

儿科病房常见病与儿童疾病综合管理关系的探讨

目的：探讨5岁以内儿科住院病例常见病与儿童疾病综合管理(IMCI)的关系。方法：分析该院1995～2000年住院的1周至5岁的肺炎、腹泻病、营养不良、麻疹和疟疾3 468例次。结果：①肺炎和腹泻病分别占5种疾病的 62.1%和 34.1%；5种疾病并发症中营养不良最常见(62.1%)。②1周至2月住院患儿中前3位死因依次为：肺炎(32.1%)、晚期新生儿高胆红素血症(25.0%)和维生素K缺乏症(23.2%)，常见病则以晚期新生儿高胆红素血症最多见(43.8%)；2月至5岁住院患儿中前3位死因依次为肺炎(25.4%)、颅内感染(23.6%)和败血症(10.9%)，常见病则以肺炎(20.2%)、急性上呼吸道炎(16.8%)和腹泻病(10.5%)多见。③5种疾病患儿占儿内科和传染科同期住院人数的 21.0%和 2.1%，儿内科住院病例占同期门、急诊人数的 1.2%。结论：除肺炎、腹泻病和营养不良外，该地区的IMCI中，1周至2月的患儿应包括晚期新生儿高胆红素血症和维生素K缺乏症，2月至5岁患儿应包括急性上呼吸道炎和颅内感染。应加强门、急诊工作和儿内科与传染科的合作。     

苏州地区14994例儿童呼吸道感染细菌病原学特点

目的 了解儿童呼吸道感染的细菌病原学特点。方法 收集2005 年11 月至2014 年10 月连续9 年因呼吸道感染入住苏州大学附属儿童医院的14 994 例儿童的病例资料进行回顾性分析。结果 14 994 份呼吸道感染患儿的痰标本中,细菌培养阳性3 947 份,总阳性检出率为26.32%。第1 位细菌病原为肺炎链球菌(12.79%),其次为流感嗜血杆菌(5.02%)、卡他莫拉菌(2.91%)。在不同年份、不同季节、不同年龄段儿童细菌检出率差异有统计学意义(P<0.01)。入院前未使用过抗菌药物的患儿痰细菌培养阳性率高于使用过抗菌药物的患儿(P<0.01)。院外病程<1 个月组、1~3 个月组及>3 个月组患儿痰培养细菌检出率差异有统计学意义(P<0.05)。肺炎链球菌、卡他莫拉菌、鲍曼不动杆菌的阳性检出率随病程的延长呈上升趋势(P<0.05)。结论 肺炎链球菌是引起儿童呼吸道感染的最常见细菌病原,其次为流感嗜血杆菌和卡他莫拉菌。各种细菌在不同的年份、不同的季节、不同的年龄阳性检出率有差异。疾病病程与院外抗菌药物使用对细菌的阳性检出率有影响。     

Outbreak of human metapneumovirus infection in norwegian children

INTRODUCTION: Human metapneumovirus (hMPV) was recently discovered in children with acute respiratory tract infection. We have studied the occurrence of hMPV and report clinical findings of 50 hMPV-infected children who were hospitalized during an outbreak in Norway. METHODS AND POPULATION: During 5 months from November 15, 2002 to April 14, 2003 we collected nasopharyngeal aspirate specimens from 236 children admitted because of respiratory tract infection (RTI). Samples were analyzed for influenza virus A/B, parainfluenza viruses 1, 2 and 3 and respiratory syncytial virus by direct immunofluorescence assays and cell culture. Rhinovirus, adenovirus and hMPV were identified by polymerase chain reaction. RESULTS: Human metapneumovirus was identified in 50 of 236 children (21%). Most (41 of 50) hMPV-infected children were hospitalized between November 15 and January 15, and during these 2 months hMPV was the most common isolate (41 of 72 isolates; 57%). Respiratory syncytial virus was identified in 36 children (15%), among whom 34 were admitted after the hMPV outbreak.The median age of hMPV-infected children was 12 months (range, 1 to 115 months), and one-half of the children had an underlying chronic disease. The most common symptoms were fever (86%), cough (90%), dyspnea (80%), wheezing (56%), rhinorrhea (44%), anorexia (48%) and vomiting (36%). Eight (16%) had an upper respiratory tract infection (rhinopharyngitis, n = 6; laryngitis, n = 2), 24 (48%) had bronchiolitis and 17 (34%) had pneumonia. Two-thirds with a lower RTI also had signs of upper RTI. Fourteen (28%) children needed supplemental oxygen, 1 was treated with continuous positive airway pressure and 2 were ventilated mechanically. CONCLUSION: Human metapneumovirus was the most common virus isolate during the winter season 2002 to 2003 in children hospitalized for respiratory tract infection. Upper respiratory tract infections and mild to severe bronchiolitis were most common, but a relatively high proportion of hospitalized children developed severe pneumonia.     

Viral aetiology of lower respiratory tract infection in young Malaysian children

OBJECTIVE: To study the viral aetiology of lower respiratory tract infection (LRTI) in young Malaysian children. METHODOLOGY: A retrospective review was performed of LRTI patients aged less than 24 months who were admitted to the University Malaya Medical Centre between 1982 and 1997. Respiratory viruses in their nasopharyngeal secretion were identified by indirect immunofluorescence, viral culture, or both. RESULTS: A total of 5691 children were included in the study. The mean age was 8.6 +/- 6.6 months and the M:F ratio was 1.6:1. The most common diagnosis was pneumonia (52%) followed by bronchiolitis (45%) and croup (2%). Positive viral isolation rate was 22.0%. Respiratory syncytial virus (RSV) was the commonest virus isolated (84%), followed by parainfluenza virus (8%), influenza virus (6%) and adenovirus (2%). Patients with positive virus isolation were younger (7.8 +/- 6.2 vs 8.7 +/- 6.7 months, P = 0.0001) and were more likely to have bronchiolitis. CONCLUSION: Young Malaysian children admitted with LRTI had a 22% viral isolation rate and RSV was the commonest virus isolated.     

Croup: an 11-year study in a pediatric practice

The etiology and epidemiology of croup were studied in a pediatric group practice over an 11-year period, 1964 to 1975. Croup was diagnosed in 951 instances in 6,165 cases of lower respiratory tract infection (LRI) studied. As census figures of the practice clientele were available, attack rates were calculated. The incidence of total LRI was highest in the first year of life. In contrast, the attack rate for croup was highest in the second year of life; the rate declined gradually after that age. Croup was not diagnosed in the first month of life. Boys were 1.43 times more likely to develop croup than were girls. Three hundred sixty agents were isolated from the 951 croup cases. The parainfluenza viruses accounted for 74.2% of all isolates; 65% of the parainfluenza isolates were classified as parainfluenza virus type 1. Respiratory syncytial virus, influenza viruses A and B, and Mycoplasma pneumoniae were the only other agents isolated in appreciable numbers. The propensity of various agents to produce croup symptoms in children with LRI due to specific microorganisms was 58% for parainfluenzae type 1,60% for parainfluenzae type 2, and 29% for parainfluenzae type 3; similar figures for the other agents varied from 5% to 16%. The role of the various agents in the etiology of croup varied with patient age and depended on the propensity of the agent to produce the croup syndrome and the frequency of isolation of the agent at that age. The parainfluenza viruses were the most important croup agents at all ages; respiratory syncytial virus caused croup in children less than 5 years of age whereas the influenza viruses and M pneumoniae were significant causes of croup only in children more than 5 to 6 years old. Croup occurred predominately in late fall and early winter, times when the parainfluenza viruses, especially type 1, occurred most frequently. The epidemiology of croup differs from that of bronchiolitis, pneumonia, and tracheobronchitis; knowledge of this should be helpful to the clinician caring for children with LRI.     

Epidemiology and clinical presentation of respiratory syncytial virus infection in a rural area of southern Mozambique

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection (LRTI) in infants throughout most of the world, but little is known about RSV infection in Africa where LRTI are among the leading causes of infant and childhood death. METHODS: The study took place in a rural district hospital in southern Mozambique between October, 1998, and May, 2000. From all children (n = 5635) <1 year of age presenting to an outpatient department with cough or nasal secretion and all children (n = 1307) <5 years of age admitted to hospital with a LRTI, a nasopharyngeal aspirate was collected and tested for RSV by enzyme-linked immunosorbent assay (Abbott). RESULTS: RSV infection was found in 8.6% of study infants in the outpatient department and 10.6% of admitted children with LRTI. Cases presented in predictable yearly outbreaks during the warm and rainy season. Lower respiratory tract involvement was frequent (59.7%). Cough, chest indrawing and increased respiratory rate were all independently related to RSV infection. Wheezing was infrequent. Bacterial coinfection (4.6%) and the case-fatality rate (3.4%) were low. CONCLUSIONS: There is a substantial burden of disease attributable to RSV infection in this rural African setting, with the highest incidence and severity occurring in young infants.