Human metapneumovirus in patients with respiratory tract infection in Kuwait

Human metapneumovirus (hMPV) has been recognized as an important cause of respiratory tract infections in all age groups and in all geographical area. The role of hMPV in causing respiratory tract infections in Kuwait was not yet investigated. The aim of this study was to determine the prevalence of hMPV infection in Kuwait among patients with respiratory tract infection with respect to other respiratory viruses. During January–December 2009, 460 respiratory samples from 388 patients with respiratory tract infection were collected from different hospitals. They were tested for hMPV RNA by real‐time PCR, and for other respiratory viruses by conventional PCR. Out of 388 patients, 110 (28%) were positive for viral respiratory infections; 21 (5.4%) were positive for hMPV, 29 (7.5%) were positive for rhinovirus, 13 (4%) were positive for respiratory syncytial virus, and 10 (3%) were positive for adenovirus. Most (n = 19, 90.5%) of hMPV‐positive patients were admitted to the intensive care unit, 76% of them were of age 2 years and below, and 24% of age 59 years and above. All hMPV‐positive elderly patients had pneumonia while 50% of hMPV‐positive infants had bronchopneumonia. Children with hMPV/rhinovirus co‐infection (n = 3, 1%) had recurrent chest infection and frequent intensive care unit admission. The hMPV infection was mostly detected between December and May, and genotype B was more prevalent than genotype A. This is the first study demonstrating the prevalence of hMPV infection in Kuwait, and suggests that hMPV infection is prevalent in infants and elderly patients with lower respiratory tract infection. J. Med. Virol. 83:1811–1817, 2011. © 2011 Wiley‐Liss, Inc.     

Epidemiology and genetic variability of human metapneumovirus during a 4‐year‐long study in Southeastern Brazil

Epidemiological and molecular characteristics of human metapneumovirus (hMPV) were compared with human respiratory syncytial virus (hRSV) in infants and young children admitted for acute lower respiratory tract infections in a prospective study during four consecutive years in subtropical Brazil. GeneScan polymerase chain assays (GeneScan RT‐PCR) were used to detect hMPV and hRSV in nasopharyngeal aspirates of 1,670 children during January 2003 to December 2006. hMPV and hRSV were detected, respectively, in 191 (11.4%) and in 702 (42%) of the children admitted with acute lower respiratory tract infections at the Sao Paulo University Hospital. Sequencing data of the hMPV F gene revealed that two groups of the virus, each divided into two subgroups, co‐circulated during three consecutive years. It was also shown that a clear dominance of genotype B1 occurred during the years 2004 and 2005, followed by genotype A2 during 2006. J. Med. Virol. 81:915–921, 2009. © 2009 Wiley‐Liss, Inc.     

Epidemiological and clinical features of hMPV, RSV and RVs infections in young children.

BACKGROUND: Human metapneumovirus (hMPV) has recently been isolated from children with acute respiratory tract infections (RTIs). The epidemiological and clinical characteristics of hMPV infection need further investigation. OBJECTIVES: The purpose of this study was to compare the clinical features of hMPV, respiratory syncytial virus (RSV) and rhinoviruses (RV) infections in children less than 3 years of age presenting to an emergency department with acute respiratory illness. STUDY DESIGN: From December 2002 to April 2004, all children under age three (n=931) admitted for acute respiratory illness to Dijon Hospital, France, were investigated for respiratory viruses in nasal washes. RESULTS: hMPV was detected in 6% of children (in 10.1% (n=38) the first winter and in 3.3% (n=17) the second winter); RSV was detected in 28.5% of the children, while rhinoviruses were found in 18.3%. Five hMPV-infected children had evidence of dual infection, two with RSV and three others with RV. The median age of the patients with hMPV infection was 6 months, and the main clinical symptoms were rhinorrhea (74.5%) and cough (67%). A lower tract disease occurred in 66% of hMPV-positive patients. Gene sequencing of hMPV isolates revealed co-circulation of the two major groups of hMPV during the study period; no difference in pathogenicity was found. There was no difference in the prevalence of bronchiolitis where hMPV, RSV or rhinoviruses were present. Asthma was found more often in hospitalized children with hMPV and rhinoviruses than among those with RSV (p<0.001). CONCLUSIONS: These results provide further evidence of the importance of hMPV as a pathogen associated with respiratory tract infection in children.     

Newly identified respiratory viruses associated with acute lower respiratory tract infections in children in Lanzou,China, from 2006 to 2009

Nasopharyngeal aspirates were collected from 813 children <14 years old with acute lower respiratory tract infections in Lanzhou, China, from December 2006 to November 2009. PCR or RT-PCR was used to screen for the presence of 10 respiratory viruses. Viral agents were identified in 73.92% (601/813) of specimens, including RSV in 40.71%, hMPV in 6.15%, IFVA in 7.13%, IFVB in 0.98%, PIV1-3 in 7.87%, HCoV-HKU1 in 2.21%, HCoV-NL63 in 3.81%, HRV in 19.93%, AdV in 7.50% and HBoV in 11.56%. Two or more viruses were detected in 34.44% (280/813) of cases. The newly identified respiratory viruses, HBoV, hMPV, HCoV-HKU1 and HCoV-NL63, accounted for 22.01% of the detected viral pathogens. RSV and HRV were frequently detected in patients with bronchiolitis, and hMPV was frequently associated with pneumonia. HCoV-NL63 was found to be one of the causative agents of acute respiratory wheezing in young children. No seasonal variation was found in the incidence of detection of HCoV-HKU1, HCoV-NL63 or HBoV. This 3-year study demonstrated that viral pathogens play an important role in children with ALRTIs, and more attention should be paid to these newly identified viral agents.     

Genotype variability of human metapneumovirus, South Korea

Human metapneumovirus (hMPV), a virus causing lower respiratory tract infections in children, is classified two major groups or genotypes of hMPV and recently existence of multiple lineages has been suggested. The purpose of this study was to examine the extent of genetic variation and circulation pattern of hMPV in Korea. Between January 2005 and April 2007, nasopharyngeal aspirates were collected from 1,214 children <16 years of age hospitalized with acute respiratory tract infection at Sanggyepaik Hospital. Nasopharyngeal aspirates were tested for common respiratory pathogens using immunofluorescence or multiplex RT-PCR. RT-PCR was used to detect hMPV. The PCR products were purified and subsequently sequenced directly on both strands. hMPV was detected in 8.4% (102/1,214) of nasopharyngeal aspirates from children with acute respiratory tract infection. The 102 hMPV strains detected in this study were classified into two distinct F lineages, 87 strains belonged to genogroup A2 (A2a in 42, A2b in 45) and 15 strains to genogroup B. All hMPV subtypes except A1 co-circulated in Korean population. Although alternating predominance of hMPV subtypes from year to year could not be found, the changing predominance of sublineage A2a and A2b was demonstrated.     

Association of meteorological factors with childhood viral acute respiratory infections in subtropical China: an analysis over 11 years

The objective of this study was to obtain a better understanding of the effects of meteorological factors on the prevalence and seasonality of common respiratory viruses in China, which has a subtropical climate. A retrospective study was conducted by identifying children admitted to a hospital with acute respiratory infections due to seven common viruses between January 2001 and December 2011. A total of 42,104 nasopharyngeal samples were tested for respiratory syncytial virus (RSV), influenza A and B viruses (IV-A and IV-B), parainfluenza viruses 1-3 (PIV-1, PIV-2, PIV-3), and adenovirus (ADV) by direct immunofluorescence assay. Meteorological data were obtained from Suzhou Weather Bureau. Correlations of viral prevalence with meteorological factors were evaluated using Spearman rank correlation and partial correlation. Multivariate time-series analysis including an autoregressive integrated moving average (ARIMA) model and generalized linear Poisson models was conducted to study the effect of meteorological factors on the prevalence of respiratory virus infection. RSV and IV-A activity showed distinctive winter peak, whereas PIV-3 and ADV peaked in the summer. Incidence of RSV was correlated with low environmental temperature, and PIV-3 only with high temperature. IV-A activity was correlated with both low temperature and high relative humidity. ADV activity was correlated with high total rainfall. In the ARIMA model, RSV-associated hospitalizations were predictable, and the monthly number of RSV cases decreased by 11.25 % (95 % CI: 5.34 % to 16.79 %) for every 1 °C increase in the average temperature. Seasonality of certain respiratory virus may be explained by meteorological influences. The impact of meteorological factors on the prevalence of RSV may be useful for predicting the activity of this virus.     

The highest prevalence of human metapneumovirus in Ahwaz children accompanied by acute respiratory infections

PURPOSE: The newly described human metapneumovirus (hMPV) has been recently discovered as an etiological agent of acute respiratory infections (ARTI) in infants and children. The aim of this study was to determine the prevalence of hMPV and its potential role as causative agent of ARTI in Ahwaz children. METHODS: In the present study, we examined 124 nasal swabs from infants affected by ARTI for the presence of hMPV by RT-PCR technique. RESULTS: Sixty-eight out of 124 (54.4%) cases were positive for hMPV which is the highest incidence of hMPV ever reported in the world, 94.1% of positive cases belonged to genotype A; whereas no B genotype was detected. Our positive hMPV children were affected by upper (URTI) as well as lower respiratory tract infection (LRTI); however, LARTIs had higher prevalence. CONCLUSIONS: We suggest a probable role of F protein alteration as the causative agent for the highest prevalence of hMPV infection among Ahvaz children.     

Human metapneumovirus associated with respiratory tract infections in a 3-year study of nasal swabs from infants in Italy

The newly described human metapneumovirus (hMPV) is reported here to be more commonly associated with lower respiratory tract disease. The present study examined nasal swab specimens from 90 infants with acute respiratory tract infections in Pisa, Italy, over a period of three respiratory virus seasons. The incidence of infection varied in each of the 3 years, with the rates of positivity for hMPV being 7% in 2001 but 37 and 43% in 2000 and 2002, respectively. hMPV was noted to occur seasonally in a pattern typical of the frequency of occurrence of respiratory syncytial virus. More than one-half (14 of 23) of the infants infected with hMPV had bronchopneumonia. One-third (9 of 23) of the hMPV-infected patients were also infected with another respiratory virus, a relationship that has not previously been reported. Mixed infections did not account for a higher percentage of cases of bronchopneumonia than hMPV infection alone did. Furthermore, 7 of 17 infants whose plasma was also tested for hMPV RNA were demonstrated to have virus in both nasal swab and blood specimens. The study indicates that hMPV is seen as commonly as other respiratory viruses, may be associated with severe respiratory disease in infants, can establish mixed infections with other respiratory viruses, and has a seasonal occurrence.     

Comparison of the seroprevalence of human metapneumovirus and human respiratory syncytial virus

Human metapneumovirus (hMPV) is a virus that induces human respiratory syncytial virus (hRSV)-like illnesses, ranging from upper respiratory tract infection to severe bronchiolitis and pneumonia. The 100 serum samples from children aged 1 month to 5 years were tested for the presence of hMPV and hRSV antibodies using an indirect immunofluorescence assay and a neutralizing-antibody assay, respectively. The seroprevalence of hMPV was significantly lower than that of hRSV in children over 4-months-old (43% vs. 60%, P < 0.025), and the difference was particularly notable between the ages of 4 months and 1 year (11% vs. 48%, P = 0.006). The results suggest that primary infection with hMPV occurs somewhat later than that with hRSV.     

Seasonality and prevalence of respiratory pathogens detected by multiplex PCR at a tertiary care medical center

Respiratory tract infections (RTIs) are a leading cause of mortality and morbidity. Seasonality has been reported for many viruses, including influenza virus, respiratory syncytial virus (RSV), and the recently described human metapneumovirus (hMPV). We hypothesize that the availability of rapid, multiplex PCR diagnostics will provide better clinical care and new insights into the etiology and clinical spectrum of RTIs. We conducted a retrospective analysis of the incidence of respiratory pathogens at a 500-bed adult and 154-bed pediatric hospital tertiary care center. A total of 939 specimens from patients with an age range of 5 days to 91 years (median, 2 years) were tested by a multiplex respiratory pathogen PCR from November 14, 2011 to November 13, 2012. Sixty-five percent of specimens were positive for at least one pathogen. As the age of the patient increased, the positivity rate for the PCR decreased proportionately. Rhinoviruses/enteroviruses (Rhino/Entero) were the most prevalent (34.3 %) followed by RSV (19.2 %) and hMPV (6.2 %). Twelve percent of the positive samples were positive for multiple analytes, with Rhino/Entero and RSV being the most common combination. The peak months were September and May for Rhino/Entero infections, January for RSV and February for coronavirus. hMPV peaked 2 months after RSV, as has been observed recently in other studies. Multiplex PCR provides rapid diagnostic information that can be used to make knowledgeable clinical decisions and potentially reduce the use of antibiotics. Active respiratory PCR surveillance could also predict seasonal respiratory epidemics to allow for adequate planning of additional infection control measures.     

Human metapneumovirus infection in hospital referred South African children

Human metapneumovirus (hMPV) was first described in Dutch children with acute respiratory symptoms. A prospective analysis of the epidemiology, clinical manifestation, and seroprevalence of hMPV and other respiratory viruses in South African children referred to hospital for upper or lower respiratory tract infection were carried out during a single winter season, by using RT-PCR, viral culture, and enzyme-linked immunosorbent assays. In nasopharyngeal aspirates from 137 children, hMPV was detected by RT-PCR in 8 (5.8%) children (2-43 months of age) as a sole viral pathogen, respiratory syncytial virus (RSV) in 21 (15%), influenza A virus in 18 (13%) and influenza B virus in 20 (15%). Pneumonia was diagnosed in seven children and upper respiratory tract infection in one of the hMPV-infected children. One hMPV-infected child was admitted to the intensive care unit in need of mechanical ventilation and one child was infected with human immunodeficiency virus (HIV). No statistically significant differences were found between hMPV, RSV, and influenza virus infected groups with regard to clinical signs and symptoms and chest radiograph findings. The seropositive rate of hMPV specific IgG antibodies was 92% in children aged 24-36 months, the oldest seronegative child in our study was 7 years and 6 months of age. In conclusion, hMPV contributes to upper and lower respiratory tract morbidity in South African children.     

人偏肺病毒感染住院儿童的临床特征及病毒基因特性分析

目的 了解急性呼吸道感染住院儿童中人偏肺病毒(hMPV)的感染情况、临床特征及人偏肺病毒基因特性.方法 对2006年2月至5月、2008年3月至4月及2008年9月至2009年2月收集的天津市儿童医院急性呼吸道感染住院儿童的310份鼻咽吸取物标本进行巢式PCR检测hMPV N基因片段,并对其中17株N基因片段进行序列测定,分析序列特征并绘制种系发生树.收集所有阳性患者的临床资料.同时采用多重PCR对N基因阳性标本进行其他常见呼吸道病毒的检测.结果 310份标本中共检出20份(6.5%)hMPV.hMPV阳性患儿的年龄中位数为15.0个月(16天～9岁),其中≤2岁患儿占90.0%(18/20).男性占60.0%(12/20).17株N基因种系发生树分析显示,11株为A2b亚型.20例hMPV阳性患儿的临床诊断均为支气管肺炎,占所有采集的肺炎患儿标本的7.1%(20/282),其临床症状以咳嗽、喘息、呼吸急促、发烧等常见.35%(7/20)需要重症监护,15%(3/20)需要吸氧治疗.平均住院时间为(11.9±4.8)d.A、B型间临床特征未见明显差别.hMPV无明显流行高峰.2例hMPV阳性患儿分别与腺病毒和鼻病毒混合感染.结论 hMPV可引起婴幼儿肺炎等严重疾病.天津地区流行的hMPV以A2b为优势流行型.     

10456例住院患者医院感染调查分析

目的为了解我院医院感染的发病情况及影响因素。方法对2004—2006年6、12月份出院患者医院感染情况进行回顾性调查分析。结果医院感染发病率呈逐年下降趋势，其中下呼吸道感染、上呼吸道感染占主要构成，下呼吸道感染构成比为39．7％，上呼吸道感染构成比为31．9％，医院感染发病率与季节及平均住院日有直接关系，平均住院日越长，医院感染发病率越高。结论减少平均住院日，加强消毒隔离，有效通风，改善环境，控制呼吸道感染，根据药敏试验合理使用抗菌药物可以有效降低医院感染发病率。