Rapid detection and clinical features of infants and young children with acute lower respiratory tract infection due to respiratory syncytial virus

During December to the end of February of 2003 and 2004, a total of 282 nasopharyngeal aspirates were obtained from infants and young children admitted to the Buraidah Maternity and Pediatric Hospital, Al-Qassim, Saudi Arabia, and clinically diagnosed as suffering from acute lower respiratory tract infections. The aspirates were tested for the presence of respiratory syncytial virus using direct fluorescein-labeled monoclonal antibody assay. Of the 282 specimens, 128 (45.4%) were found to be positive for respiratory syncytial virus. The most positive specimens came from patients less than one year old (51.3%), and were associated with bronchopneumonia (56.7%) or bronchiolits (55.4%). Coughing (100%) and tachpnea (98%) were significantly more frequent in infants with respiratory syncytial virus infection, followed by wheezing, crepitation and retraction, each representing 66%. Three deaths were reported. The availability of a rapid viral diagnostic assay will be an important tool for physicians to make more accurate treatment decisions and therefore reduce unnecessary antibiotic usage and hospital stay for the patients.     

西藏地区儿童急性呼吸道感染中呼吸道合胞病毒的初步研究

本研究为了解西藏地区儿童急性呼吸道感染中呼吸道合胞病毒(Respiratory syncytial virus,RSV)及基因型别。首先采用直接免疫荧光法检测2011年4～7月西藏自治区人民医院儿科病房因急性呼吸道感染住院患儿的鼻咽分泌物标本中7种常见的呼吸道病毒及人类偏肺病毒(Human metapneumovirus,hMPV)的抗原。然后对RSV抗原阳性的标本分别提取RNA,用逆转录-巢式聚合酶链反应法(Nest-PCR)确定RSV型别,同时用实时荧光PCR(Real-Time PCR)方法进行验证。再通过对G蛋白基因PCR扩增产物序列测定确定RSV的基因型。通过与GenBank中不同地区RSV分离株的G蛋白基因序列比对,了解西藏地区RSV G蛋白的结构特点及变异情况。结果表明,从167例标本中检测出呼吸道病毒抗原阳性的为65例,总阳性率为38.9%(65/167),其中RSV 45例,占阳性标本的69.2%(45/65),对其中42例RSV阳性标本进行了PCR分型,其中40例为A亚型,2例为B亚型。对7株A亚型RSV G蛋白基因PCR产物测序结果显示,全部为GA2基因型。西藏RSV与RSV原型株A2株核苷酸的同源性为90.7%～91.8%,氨基酸的同源性只有86.5%～87.2%。氨基酸的变异主要集中在胞外区一个高度保守序列的两端。7株西藏A亚型RSV G蛋白的核苷酸序列与GenBank中不同的RSV分离株相比同源性为90.7%～91.8%。西藏地区2011年春季小儿急性呼吸道感染的病毒病原主要为呼吸道合胞病毒,A亚型是2011年西藏地区的流行优势型别,其G蛋白胞外区基因具有较高的变异性。     

The changing face of pediatric respiratory tract infections: how human metapneumovirus and human bocavirus fit into the overall etiology of respiratory tract infections in young children

Lower respiratory tract infections are one of the leading causes of morbidity and mortality in children worldwide. Recent technological advances in the field of molecular biology have allowed virologists to detect many previously undetected viral pathogens. Two of these, human metapneumovirus (hMPV) and human bocavirus (HBoV), are of particular clinical interest to pediatric health care providers. This review discusses the most common viral respiratory infections in children, explores the role of newly discovered respiratory pathogens, and describes techniques for the diagnosis of viral respiratory infections.     

Surveillance of acute respiratory virus infections in general practice

The ordinary postal system provides a simple method for the transportation of specimens for virus isolation to the laboratory. This was used to carry out an epidemiological survey, in general practice, of respiratory viruses in patients with acute respiratory disease. Three distinct outbreaks of myxovirus infections were recognized and most other types of respiratory viruses were isolated sporadically. After the initial “pilot” phase of the study an isolation rate of 24% was obtained over the months from October 1968 to June 1969 (20% isolations from adults'' specimens and 29% from those of children).     

Prevalence and structure of acute respiratory virus infections

Information on epidemiology of acute respiratory virus infections (ARVI) is reviewed and analyzed. In addition to influenza viruses, the role of respiratory syncytial viruses (RSV), rhino- and adenoviruses, as well as other viruses, in the development of respiratory diseases, especially in newborns, young children and elderly persons, is emphasized. A high proportion of RSV in the etiology the severe forms of ARVI and in the development of intrauterine infection is pointed out. The conclusion has been made that the identification of the causative agents of ARVI with the use of modern methods makes it possible to determine the real role of each of the pathogens in the formation of the severe forms of diseases, as well as the expediency of vaccinal prophylaxis.     

The epidemiology of acute intestinal infections of undetermined etiology in children

Materials obtained in the study of conditions for contacting acute enteric infections of uncertain etiology, based on the analysis of the age structure of patients, the structure of clinical diagnoses and the monthly dynamics of cases registered in one of the districts of Moscow for 3 years (1984-1986), are presented. An important role of the alimentary factor in the spread acute enteric infections of uncertain etiology among the population of different age groups and everyday contacts in the spread of such infections among young children has been shown. The authors put forward a suggestion concerning the formation of natural immunity to infective agents, serving as etiological factors in the development of enteric infections of uncertain etiology, in children of preschool age.     

Hypoxaemia in young Kenyan children with acute lower respiratory infection.

OBJECTIVES--To determine the prevalence, clinical correlates, and outcome of hypoxaemia in acutely ill children with respiratory symptoms. DESIGN--Prospective observational study. SETTING--Paediatric casualty ward of a referral hospital at 1670 m altitude in Nairobi, Kenya. SUBJECTS--256 Infants and children under 3 years of age with symptoms of respiratory infection. MAIN OUTCOME MEASURES--Prevalence of hypoxaemia, defined as arterial oxygen saturation < 90% determined by pulse oximetry, and condition of patient on the fifth day after admission. RESULTS--Over half (151) of the children were hypoxaemic, and short term mortality was 4.3 times greater in these children. In contrast, the relative risk of a fatal outcome in children with radiographic pneumonia was only 1.03 times that of children without radiographic pneumonia. A logistic regression model showed that in 3-11 month old infants a respiratory rate > or = 70/min, grunting, and retractions were the best independent clinical signs for the prediction of hypoxaemia. In the older children a respiratory rate of > or = 60/min was the single best clinical predictor of hypoxaemia. The presence of hypoxaemia predicted radiographic pneumonia with a sensitivity of 71% and specificity of 55%. CONCLUSIONS--Over half the children presenting to this referral hospital with respiratory symptoms were hypoxaemic. A group of specific clinical signs seem useful in predicting hypoxaemia. The clear association of hypoxaemia with mortality suggests that the detection and effective treatment of hypoxaemia are important aspects of the clinical management of acute infections of the lower respiratory tract in children in hospital in developing regions.     

Epidemiologic features of acute viral respiratory infections in familial foci]

A study was made of the epidemiological peculiarities of viral respiratory infections of various etiology in the familial foci with the use of a methodical approach permitting to detect the true spread of infection in the familial foci, with consideration to the subclinical forme fruste of the disease and "carrier state". It appeared that in the familial foci the infectiousness of the majority of respiratory viral infections was greater than in the closed collective bodies uniting persons of the same age. The age composition of the family influences the manifestness (particularly in parainfluenza infection) and the intensity of the epidemic process characterized by the coefficient of the secondary affections. The type of the apartment, the floor on which it is located, and the number of persons residing in it had no significant influence on the spread of the viral infections in the familial foci. A definite role in this process is played by the level of specific serum antibodies in the members of the family surrounding the patient. The association of morbidity level with the antibody level proved to be the most distinct in children with influenza and adenoviral infection; this association was less significant in adults.     

Risk factors for acute respiratory tract infections in children

Acute respiratory tract infections (ARTI) are the most common cause of childhood morbidity and an important public health problem. The aim of this study was to identify the significant risk factors for ARTI in children. The study took place in Ivankovo which is a rural area of Eastern Slavonia and with small socio-economic differences. The study population were 159 children who were 3-5 years old at the time of the study, and who were registrated at doctor's office Ivankovo. The study was conducted retrospectively through a questionnaire from January 2008 to December 2008. The risk factors studied were the gender, breastfeeding history, any atopic manifestation in the form of atopic eczema, rhinoconjuctivitis and/or asthma, the size of the family, parents smoking habits and main form of childcare. The number of ARTI requiring the consultation of a doctor throughout 2007 were measured; and whether ARTI had been treated with antibiotic or there were recommendation for symptomatic treatment only. Results of this research show that the risk factor for consulting a doctor because ofARTI in children was passive exposure to cigarette-smoke. For receiving antibiotics because of ARTI in children, the risk factors were passive exposure to cigarette-smoke and atopic manifestation. By giving the available evidence, parents must be told that ceasing smoking offers a significant opportunity to reduce the risk of ARTI in their children.     

Antibody response to respiratory syncytial virus structural proteins in children with acute respiratory syncytial virus infection.

The purified respiratory syncytial virus (RSV), Randall strain contained 10 polypeptides (72,000 molecular weight [72K], 66K, 48K, 42K, 40K, 36K, 30K, 23K, 18K, and 15K), 8 of which proved to be virus specific, and polypeptides 48K and 23K were glycosylated. In addition, a high-molecular-weight (150K), virus-specific glycopolypeptide was immunoprecipitated from RSV-infected cell lysate. The antibody response in human sera serially collected from children with primary RSV infection was mainly directed against the polypeptides 30K, 48K, and 72K. The immune response against the other viral proteins was also already detectable in the acute-phase sera. These results indicate that the immune response in RSV infection differs significantly from those for other diseases caused by paramyxoviruses.     

Immunological research and criteria for determining the etiology of acute bronchitis in young children

In the determination of the etiology of acute bronchitis in children, a complex of microbiological and immunological methods should be used. The isolation of Streptococcus pneumoniae and Haemophilus influenzae at a concentration of greater than or equal to 10(4) cels/ml from tracheobronchial washings is the early and most significant method for the determination of the etiology and therapy of acute bronchitis. On the basis of microbiological and immunobiological criteria, the etiological role of S. pneumoniae has been determined in 78% of patients and that of H. influenzae, in 48% of patients, mainly in association with pneumococci.     

TT virus loads and lymphocyte subpopulations in children with acute respiratory diseases

TT virus (TTV) produces chronic plasma viremia in around 90% of healthy individuals of all ages and has, therefore, been proposed as a commensal human virus. We recently demonstrated that in children hospitalized for acute respiratory diseases high TTV loads were associated with severe forms of disease. Here, we report that in such children TTV loads showed an inverse correlation with the percentage of circulating total T and helper T cells and a direct correlation with the percentage of B cells. Thus, florid TTV replication might contribute to lymphocyte imbalances and, possibly, immunosuppressive effects, thus resembling related animal viruses.     

Severity of respiratory signs and symptoms and virus profiles in Japanese children with acute respiratory illness

Associations between the severity of respiratory signs and symptoms and the respiratory viruses identified in 214 Japanese children with acute respiratory illness (ARI) enrolled between January and December 2012 were studied. Respiratory rate, wheezing, cyanosis, and the use of accessory muscles were used as indices of respiratory severity and phylogenetic analysis of the viruses identified in these children was performed. Respiratory viruses such as respiratory syncytial virus (RSV), human rhinovirus (HRV), human parainfluenza virus (HPIV), and human metapneumovirus (HMPV) were prevalent, being detected in approximately 70% of the patients (151/214 patients). Co‐detection of viruses occurred in about 9% of patients. RSV was identified more frequently in cases scored as moderate/severe than in those scored as mild (P < 0.05). Severity scores of patients with RSV were significantly higher than those of cases with HPIV. Moreover, severity scores in patients with mild disease and co‐detections were higher than in those in whom only HPIV or adenovirus was detected. Phylogenetic analysis showed that many genotypes of HRV‐A and ‐C with wide genetic divergence were associated with acute respiratory illness (ARI). On the other hand, only a limited number of genotypes of RSV were associated with ARI. HPIV and HMPV were associated with ARI at similar frequencies. These results suggest that different respiratory viruses with unique genetic characteristics can be found in patients with mild to severe ARI.     

2009～2010年上海地区急性呼吸道感染病毒病原谱分析

调查2009~2010年上海地区人群急性呼吸道感染(ARTI)的病毒性病原,探讨2009甲型H1N1流感暴发背景下呼吸道感染病毒病原谱的构成。采用套式多重反转录-聚合酶链反应(RT-PCR)和实时荧光定量RT-PCR方法,对来自2 044例患者的2 044份标本(包括2 005份鼻咽拭子和39份肺泡灌洗液),同时检测腺病毒(ADV)、副流感病毒(PIV)、甲型流感病毒(FluA)、乙型流感病毒(FluB)、微小核糖核酸病毒、呼吸道合胞病毒(RSV)、人偏肺病毒(hMPV)、冠状病毒(CoV)和人博卡病毒(HBoV)。其中,656(32.09%)份标本经呼吸道病毒检测为阳性,52份标本为双重感染。FluA检出率最高(13.36%),其后依次为微小核糖核酸病毒(10.23%)、FluB(4.84%)、ADV(1.96%)、PIV(1.76%)、RSV(1.32%)、CoV(0.59%)、hMPV(0.39%)和HBoV(0.20%)。但各月病毒检出率分布不均,2009和2010年呼吸道病毒检出率高峰出现在当年11月(53.07%和65.59%),低谷都出现在当年5月,且2009年5~9月的病毒检出率高于2010年同期(32.02%vs15.38%,P<0.05)。其中,2009甲型H1N1流感暴发导致2009年10月~2010年1月2009甲型H1N1流感病毒占当月检出FluA的100%,2009年6~9月也占当月检出FluA的较高比率,依次为90.91%(20/22)、75.00%(15/20)、48.00%(12/25)和56.25%(18/32)。比较甲型H3N2流感病毒和2009甲型H1N1流感病毒分别在上呼吸道感染(URTI)和下呼吸道感染(LRTI)中的检出率,无统计学差异(URTI,85.29%vs76.61%;LRTI,14.71%vs23.39%;P>0.05)。呼吸道病毒检出率还与年龄相关,0~4岁组和5~14岁组病毒检出率高于其他年龄组。在0~4岁及≥65岁组中,微小核糖核酸病毒检出率最高,FluA次之;其余年龄组中FluA检出率最高。混合感染中15岁以下儿童占50%(26/52),微小核糖核酸病毒与其他病毒混合感染占84.62%(44/52)。本研究表明,上海地区2009~2010年FluA是最常见的急性呼吸道感染病原,2009甲型H1N1流感病毒成为2009年FluA的优势亚型。微小核糖核酸病毒是混合感染中最常见的病原。结果提示,应长期监测主要呼吸道病毒的活动水平,并加强对微小核糖核酸病毒流行病学和致病性的研究。