Human metapneumovirus infection among children in Taiwan: a comparison of clinical manifestations with other virus-associated respiratory tract infections

This study compared the clinical, laboratory and radiological features of infections caused by human metapneumovirus (hMPV) with other respiratory viruses. Nasopharyngeal aspirates and throat swabs were obtained from children during a 9-week period. hMPV was the virus isolated most frequently, followed by adenovirus, influenza virus A, respiratory syncytial virus and influenza virus B. hMPV-infected children were younger, and were more likely to be female, to present with feeding difficulties, a rash, tachycardia and a longer duration of fever, and to cough less frequently. Increasing interstitial infiltrates and hyperinflation were the most common radiological findings. None of the children required mechanical ventilation.     

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.     

上海地区儿童下呼吸道人类偏肺病毒感染的初步研究

目的 了解人类偏肺病毒（hMPV）在上海地区儿童下呼吸道感染中的致病情况。方法 采集2004年8月-2005年1月秋冬季节我院479例因社区获得性急性下呼吸道感染（CALRTIs）住院儿童的呼吸道分泌物标本，对直接免疫荧光法常规检测病毒阴性的259份标本用逆转录．多聚酶链反应法（RT-PCR）检测hMPVM基因。对PCR阳性产物随机挑选23份直接作核苷酸序列测定，用DNAStar软件对基因序列分析。结果 259份标本中hMPV检测阳性例数为59例（22．8％），占总例数的12．3％。冬季检测阳性率明显高于秋季（31．3％vs7．5％，P〈0．01）。5岁及以下儿童53例（89．8％），5岁以上儿童6例（10．2％）。23份hMPV阳性标本目标基因部分核苷酸序列与GenBank中公布的hMPVM基因同源性达82．8％～100％，部分氨基酸序列同源性为93．0％～100％，对核苷酸序列作基因进化树分析显示存在2种不同的基因型，以Bj1816组为代表的基因型14株，以Bj1887组为代表的基因型9株。结论hMPV是上海地区儿童CALRTIs的重要致病原，上海地区儿童感染的hMPV同时存在2种不同的基因型。     

Merkel cell polyomavirus DNA in immunocompetent and immunocompromised patients with respiratory disease

Merkel cell polyomavirus (MCPyV) was identified originally in association with a rare but aggressive skin cancer, Merkel cell carcinoma. The virus has since been found in the respiratory tract of some patients with respiratory disease. However, the role of MCPyV in the causation of respiratory disease has not been established. To determine the prevalence of MCPyV in 305 respiratory samples from immunocompetent and immunocompromised patients and evaluate their contribution to respiratory diseases, specimens were screened for MCPyV using single, multiplex, or real-time PCR; co-infection with other viruses was examined. Of the 305 samples tested, 10 (3.27%) were positive for MCPyV. The virus was found in two groups of patients: in 6 (2%) nasopharyngeal aspirate samples from children aged 26 days to 7 months who were immunocompetent; and in 4 (1.3%) of nasopharyngeal aspirate samples taken from patients aged 41 to 69 years who were severely immunosuppressed from leukemia or transplant therapy. Both groups had upper or lower respiratory tract infection. Co-infections with other viruses were found in 30% of the MCPyV positive samples. The data present a pattern of infection similar to that seen with the polyomaviruses JC and BK in which the virus is acquired during childhood, probably by the respiratory route. The viruses then establish latency and become reactivated in the event of immunosuppression.     

Lack of Marseillevirus DNA in immunocompetent and immunocompromised Italian patients

Marseilleviridae is a family of viruses which have only been propagated in acanthamoeba. Marseillevirus sequences have been recently detected in different human matrices by viral metagenomics. Single-center studies worldwide have estimated a low prevalence of marseillevirus both in symptomatic patients and in healthy donors but, to date, no informations are available on the prevalence of this giant virus in Italy. By a polymerase chain reaction targeting the ORF152 viral sequence, we tested sera from 197 immunosuppressed patients and 285 healthy donors, and 63 and 30 respiratory and cerebrospinal fluid samples, respectively, of patients with various clinical conditions and referring the Virology Division for diagnostic purposes. We observed no evidence of Marseillevirus DNA in all 575 samples tested. Marseillevirus probably does not cause infection in human.     

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 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.     

Clinical characteristics and viral load of respiratory syncytial virus and human metapneumovirus in children hospitaled for acute lower respiratory tract infection

Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are two common viral pathogens in acute lower respiratory tract infections (ALRTI). However, the association of viral load with clinical characteristics is not well‐defined in ALRTI. To explore the correlation between viral load and clinical characteristics of RSV and HMPV in children hospitalized for ALRTI in Lanzhou, China. Three hundred and eighty‐seven children hospitalized for ALRTI were enrolled. Nasopharyngeal aspirates (NPAs) were sampled from each children. Real‐time PCR was used to screen RSV, HMPV, and twelve additional respiratory viruses. Bronchiolitis was the leading diagnoses both in RSV and HMPV positive patients. A significantly greater frequency of wheezing (52% vs. 33.52%, P = 0.000) was noted in RSV positive and negative patients. The RSV viral load was significant higher in children aged <1 year (P = 0.003), children without fever and wheezing (P = 0.015 and P = 0.000), days of illness <14 days (P = 0.002), children with bronchiolitis (P = 0.012) and children with RSV single infections (P = 0.000). No difference was found in the clinical features of HMPV positive and negative patients. The HMPV viral load had no correlation with any clinical characteristics. The incidences of severe disease were similar between single infection and coinfection for the two viruses (RSV, P = 0.221; HMPV, P = 0.764) and there has no statistical significance between severity and viral load (P = 0.166 and P = 0.721). Bronchiolitis is the most common disease caused by RSV and HMPV. High viral load or co‐infection may be associated with some symptoms but neither has a significant impact on disease severity for the two viruses. J. Med. Virol. 89:589–597, 2017 . © 2016 Wiley Periodicals, Inc.

     

Detection of human coronavirus NL63, human metapneumovirus and respiratory syncytial virus in children with respiratory tract infections in south-west Sweden

Two recently detected viruses, human metapneumovirus (hMPV) and coronavirus NL63 (HCoV-NL63), have been associated with acute respiratory tract infections, particularly in young children. This study investigated the frequency of hMPV and HCoV-NL63 infections in Swedish children by screening 221 nasopharyngeal aspirates, collected between November 2003 and May 2005, from 212 children attending the paediatric department of a county hospital in Sweden or submitted from local general practitioners. The samples were originally submitted to be tested for respiratory syncytial virus (RSV), and were examined retrospectively for hMPV and HCoV-NL63 by RT-PCR. Of the 212 patients, 101 were positive for RSV (48%), 22 (10%) were positive for hMPV, and 12 (6%) were positive for HCoV-NL63. The frequency of HCoV-NL63 infection increased from 1% in 2003-2004 to 10% in 2004-2005. Sequence analysis of parts of the coronavirus genomes showed considerable similarity to the HCoV-NL63 prototype sequence. The study demonstrated that HCoV-NL63 and hMPV occur in south-west Sweden with essentially the same frequency, seasonal distribution and clinical characteristics as have been reported in other countries.     

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.     

Human metapneumovirus and human bocavirus associated with respiratory infection in Apulian population

We have studied the occurrence of hBoV, hMPV and InfA-B in an Apulian population with respiratory tract infections. During influenza season 2008-2009, 116 oropharingeal swabs were collected from patients affected by Influenza-Like Illness (ILI). The PCR products of hMPV M and HBoV NP-1 genes were sequenced. 78 out of 116 samples were positive for at least one respiratory virus; hBoV was detected in 53, hMPV in 22 and InfA-B in 41 out of 116 swabs. A high rate of hBoV infection in adult (18.9%) and elderly (26.4%) subjects was found. The co-infection rate was higher for hMPV (18/22 cases, 81.8%) compared to hBoV (26/53 cases, 49.1%), and InfA-B (25/41 cases, 61.0%). Co-infections were common in children. hBoV positive samples shared a high level of genetic similarity with the hBoV1 genotype, and hMPV positive samples clustered with A2 subgroup. Our results suggest that hBoV and hMPV play a role in ILI.     

Use of a multiplex real-time PCR to study the incidence of human metapneumovirus and human respiratory syncytial virus infections during two winter seasons in a Belgian paediatric hospital

Viruses are an important cause of acute respiratory tract infection (ARTI) in children. This study aimed to develop and evaluate a rapid molecular diagnostic test (duplex real-time PCR) for human respiratory syncytial virus (hRSV) and human metapneumovirus (hMPV), and to determine the frequency of these two viruses as causative agents of ARTI in Belgium. Nasopharyngeal aspirates were collected over two winter and spring seasons (November 2003 to May 2004 and November 2004 to May 2005) from children aged <5 years with ARTI (n = 778). The duplex real-time PCR showed a linear range of 10(4)-10(10) copies/mL for both hMPV and hRSV. Analysis of the stability of the hRSV and hMPV genomes revealed that nasopharyngeal aspirates could be stored at room temperature for up to 1 month without significant loss of detection. hRSV was detected by antigen testing and by real-time PCR; hMPV was detected by real-time PCR only. The hRSV antigen test was less sensitive than PCR, and failed to detect one-third of the hRSV infections. Overall, 54 (6.9%) and 306 (39.3%) of the 778 samples were positive for hMPV and hRSV, respectively. Both viruses infected young infants, but the mean age of infants infected by hRSV was lower than that of infants infected by hMPV (12 months vs. 17 months, respectively).