Genetic variability of human metapneumovirus amongst an all ages population in Cambodia between 2007 and 2009

A decade of human metapneumovirus in hospitalized children with acute respiratory infection: molecular epidemiology in central Vietnam, 2007-2017

Human metapneumovirus (hMPV) can cause severe acute respiratory infection (ARI). We aimed to clarify the clinical and molecular epidemiological features of hMPV. We conducted an ARI surveillance targeting hospitalized children aged 1 month to 14 years in Nha Trang, Vietnam. Nasopharyngeal swabs were tested for respiratory viruses with PCR. We described the clinical characteristics of hMPV patients in comparison with those with respiratory syncytial virus (RSV) and those with neither RSV nor hMPV, and among different hMPV genotypes. Among 8822 patients, 278 (3.2%) were hMPV positive, with a median age of 21.0 months (interquartile range: 12.7-32.5). Among single virus-positive patients, hMPV cases were older than patients with RSV (p < 0.001) and without RSV (p = 0.003). The proportions of clinical pneumonia and wheezing in hMPV patients resembled those in RSV patients but were higher than in non-RSV non-hMPV patients. Seventy percent (n = 195) were genotyped (A2b: n = 40, 20.5%; A2c: n = 99, 50.8%; B1: n = 37, 19%; and B2: n = 19, 9.7%). The wheezing frequency was higher in A2b patients (76.7%) than in those with other genotypes (p = 0.033). In conclusion, we found a moderate variation in clinical features among hMPV patients with various genotypes. No seasonality was observed, and the multiple genotype co-circulation was evident.

Burden of human metapneumovirus infections among children with acute respiratory tract infections attending a Tertiary Care Hospital, Kathmandu

BACKGROUND

Acute respiratory infections (ARIs) are one of the most common causes of mortality and morbidity worldwide. Every year millions of children suffer from viral respiratory tract infections (RTIs) ranging from mild to severe illnesses. Human Metapneumovirus (HMPV) is among the most frequent viruses responsible for RTIs. However, HMPV infections and their severity among children have not been explored yet in Nepal.

PURPOSE

Therefore, the study was focused on HMPV infections and other potential viral etiologies or co-infections using multiplex PCR among children attending Kanti Children's Hospital and assessed the clinical characteristics of the infections as well as found the co-infections. A hospital-based cross-sectional study was designed and a convenience sampling method was used to enroll children of less than 15 years with flu-like symptoms from both outpatients and inpatients departments over three months of the study period.

RESULTS

HMPV infection (13.3%) was the most predominant infection among the different viral infections in children with ARIs in Kanti Children's Hospital. The HMPV was more prevalent in the age group less than three years (21.8%). Cough and fever were the most common clinical features present in all children infected with HMPV followed by rhinorrhea, sore throat, and wheezing. HMPV-positive children were diagnosed with pneumonia (42.9%), bronchiolitis (28.5%), upper respiratory tract infections (14.3%), and asthma (14.3%). The prevalence of HMPV was high in late winter (14.3%) followed by early spring (13.5%).

CONCLUSIONS

This study provides the baseline information on HMPV and associated co-infection with other respiratory viruses for the differential diagnosis based on molecular methods and also the comparison of clinical presentations among the different respiratory syndromes.

Pediatric burden and seasonality of human metapneumovirus over 5 years in Managua, Nicaragua

BACKGROUND

Human metapneumovirus (hMPV) is an important cause of pediatric respiratory infection. We leveraged the Nicaraguan Pediatric Influenza Cohort Study (NPICS) to assess the burden and seasonality of symptomatic hMPV infection in children.

METHODS

NPICS is an ongoing prospective study of children in Managua, Nicaragua. We assessed children for hMPV infection via real-time reverse-transcription polymerase chain reaction (RT-PCR). We used classical additive decomposition analysis to assess the temporal trends, and generalized growth models (GGMs) were used to estimate effective reproduction numbers.

RESULTS

From 2011 to 2016, there were 564 hMPV symptomatic infections, yielding an incidence rate of 5.74 cases per 100 person-years (95% CI 5.3, 6.2). Children experienced 3509 acute lower respiratory infections (ALRIs), of which 160 (4.6%) were associated with hMPV infection. Children under the age of one had 55% of all symptomatic hMPV infections (62/112) develop into hMPV-associated ALRIs and were five times as likely as children over one to have an hMPV-associated ALRI (rate ratio 5.5 95% CI 4.1, 7.4 p < 0.001). Additionally, symptomatic reinfection with hMPV was common. In total, 87 (15%) of all observed symptomatic infections were detected reinfections. The seasonality of symptomatic hMPV outbreaks varied considerably. From 2011 to 2016, four epidemic periods were observed, following a biennial seasonal pattern. The mean ascending phase of the epidemic periods were 7.7 weeks, with an overall mean estimated reproductive number of 1.2 (95% CI 1.1, 1.4).

CONCLUSIONS

Symptomatic hMPV infection was associated with substantial burden among children in the first year of life. Timing and frequency of symptomatic hMPV incidence followed biennial patterns.

Epidemiology and genetic characterization of human metapneumovirus in pediatric patients from Hangzhou China

Human metapneumovirus (HMPV), which is distributed worldwide, is a significant viral respiratory pathogen responsible for causing acute respiratory tract infections (ARTIs) in children. The aim of the present study was to investigate the epidemiological and genetic characteristics of HMPV in pediatric patients in Hangzhou China following the peak of onset of coronavirus disease 2019 (COVID-19). A total of 1442 throat swabs were collected from the pediatric patients with a diagnosis of ARTI from November 2020 to March 2021. The following viruses were detected by real-time polymerase chain reaction analysis: HMPV, RSV, adenovirus, hPIV1-3, influenza A, and influenza B. A two-step method was used to amplify the F genes of the HMPV-positive samples. Following sequencing, phylogenetic analyses were conducted using the MEGA version 7 software package. Among the 1442 samples, 103 (7.14%) were positive for HMPV. No significant differences were observed in the gender distribution. The highest incidence of HMPV occurred in children older than 6 years and the lowest was noted in children younger than 6 months. Lower respiratory tract infections were diagnosed at a higher rate than upper respiratory tract infections in HMPV-infected children. Only 10 HMPV-infected children (5.41%) were inpatients compared with 93 outpatients (7.39%). Co-infection was observed in 31 HMPV-positive samples including 24 samples of double infection and seven samples of triple infection. A total of 61F gene fragments of HMPV, which were approximately 727 bp in length were successfully sequenced. All the HMPVs belonged to the genotype B and were clustered into subgenotypes B1 (1.6%, 1/61) and B2 (98.4%, 60/61). A total of four specific amino acid substitutions were noted as follows: aa280, aa296, aa392, and aa396. These substitutions were present between sequences derived from the subgenotypes B1 and B2 in the fusion open reading frame from position 244 to 429. In conclusion, the present study provided significant information regarding the epidemiological and genetic characteristics of HMPV in children living in Hangzhou. Following the first peak of the COVID-19 pandemic, HMPV was considered an important viral respiratory pathogen present in children with ARTI.

Clinical characteristics and molecular epidemiology of human metapneumovirus in children with acute lower respiratory tract infections in China, 2017 to 2019: A multicentre prospective observational study

Human metapneumovirus (HMPV) infection is one of the leading causes of hospitalization in young children with acute respiratory illness. In this study, we prospectively collected respiratory tract samples from children who were hospitalized with acute lower respiratory tract infection in six hospitals in China from 2017 to 2019. HMPV was detected in 145 out of 2733 samples (5.3%) from the hospitalized children. The majority of HMPV-positive children were under the age of two (67.6%), with a median age of one year. HMPV can independently cause acute lower respiratory tract infection in young children, while all patients showed mild clinical symptoms. Of all the co-infected patients, HMPV was most commonly detected with enterovirus (EV) or rhinovirus (RhV) (38.0%, followed by respiratory syncytial virus (RSV) (32.0%). The highest detection rate occurred from March to May in both northern and southern China. Out of 145 HMPV positive samples, 48 were successfully typed, of which 36 strains were subgrouped into subtypes A2c (75%), eight strains were included in subtype B1 (16.7%), and four strains were included in subtype B2 (8.3%). Moreover, 16 A2c strains contained 111-nucleotide duplications in the G gene. Twenty-seven complete HMPV genomes were successfully obtained, and 25 (92.6%) strains belonged to subtype A2c, whereas one strain was included in subgroup B1 and another was included in subgroup B2. A total of 277 mutations were observed in the complete genomes of 25 A2c strains. All results presented here improve our understanding of clinical characteristics and molecular epidemiology of HMPV infection in children.

Molecular epidemiological surveillance of viral agents of acute lower respiratory tract infections in children in Accra, Ghana

BACKGROUND

Acute lower respiratory tract infection (ALRTI) in children under 5 years is known to be predominantly caused by respiratory syncytial virus (RSV). In recent times, however, human metapneumovirus (HMPV) has also been implicated. This study sought to investigate and genotype respiratory syncytial virus and human metapneumovirus in children presenting with ALRTIs infection at the Princess Marie Louis Children's Hospital in Accra, Ghana.

METHODS

Children below 5 years who were clinically diagnosed of ALRTI and on admission at the study site were recruited between September 2015 and November 2016 for this study. Demographic data information was obtained by means of a standardized questionnaire; and relevant clinical information was obtained from medical records. Nasopharyngeal swabs were collected from 176 children recruited for the study. Ribonucleic acid was extracted from swabs and cDNA syntheses were performed by RT-PCR. RSV-positive amplicons were sequenced and analyzed for genotype assignment.

RESULTS

RSV and HMPV prevalence among the sampled subjects were 11.4 and 1.7% respectively. Of the RSV positives, 8/20 (40%) were RSV-A and 12/20 (60%) were RSV-B. The highest prevalence was observed in children less than 12 months old. Phylogenetic analysis of the second hypervariable region of the RSV G-gene revealed that all RSV group A viruses belonged to the "novel" ON1 genotype containing the 72-nucleotide duplication; and RSV group B viruses belong to the BA IX genotype.

CONCLUSION

RSV is frequently detected in children aged under 5 years admitted with ALRTI in Ghana. Continued surveillance of viral aetiological agents is warranted to elucidate the prevalence and transmission patterns of viral pathogens that cause respiratory tract infections among children. This will help inform appropriate intervention approaches.

Molecular detection and genetic characterization of human metapneumovirus strains circulating in Islamabad, Pakistan

Lower respiratory illness is one of the leading causes of death among children in low- and high-income countries. Human metapneumovirus (hMPV) is a key contributor to respiratory illnesses commonly reported among children and causes serious clinical complications ranging from mild respiratory infections to severe lower respiratory tract anomalies mainly in the form of bronchiolitis and pneumonia. However, due to the lack of a national surveillance system, the clinical significance of hMPV remains obscure in the Pakistani population. This study was conducted to screen throat swabs samples collected from 127 children reported with respiratory symptoms at a tertiary care hospital in Islamabad. Out of 127, 21 (16.5%) samples were positive for hMPV with its genotype distribution as A2a (10%), A2b (20%), B1 (10%), and B2 (60%). Phylogenetic analysis showed that the hMPV viruses were closely related to those reported from neighboring countries including India and China. This work will contribute to a better understanding of this virus, its diagnosis, and the handling of patients in clinical setups. Further studies at a large-scale are warranted for a better understanding of the disease burden and epidemiology of hMPV in Pakistan.

Molecular investigation of human metapneumovirus in children with acute respiratory infections in Chennai, South India, from 2016-2018

Human metapneumovirus (hMPV) has emerged as a frequent cause of acute respiratory infections (ARI) among young children. The prevalence and genetic diversity of hMPV circulating in Chennai, Southern India, has not been studied yet. Hence, this study was aimed to investigate the prevalence, co-infection with other respiratory viruses like HRSV A and B, influenza A and B, hRV and HPIV 1-4 viruses, socio-demographic associations, and genotypes of hMPV among children in Chennai. A total of 350 nasal swab specimens were collected from children with ARI during April 2016 to August 2018 and tested for hMPV by real time PCR method. In this study, hMPV was detected in 4% (14/350) of the samples. One hMPV positive sample was found to be co-infected with influenza B virus. The mean and median ages of the children with hMPV infection were 61.5 months (5.1 years) and 83 months (6.9 years), respectively. Phylogenetic analysis of the partial F gene revealed the presence of A2c subcluster among the study strains as well as with B1 and B2 lineages. The prevalence data obtained in this study is important in evaluating the role of hMPV in childhood ARI and emphasizes the importance of routine viral diagnosis in hospitals. To the best of our knowledge, this is the first study to report the prevalence, seasonality, and genetic diversity of hMPV in Chennai as well as the first study to report A2c subcluster of hMPV among children in India.

Prevalence of Human Metapneumovirus Infections in Iran: A Systematic Review and Meta-Analysis

BackgroundWe sought to systematically review the literature and perform a meta-analysis by assessing the prevalence of human metapneumovirus (hMPV) infections from a number of studies conducted in Iran. Methods: Entire studies addressing epidemiology of hMPV in Iran using data from PubMed, Scopus, Science Direct, Web of science, Google Scholar, Embase, and national Persian databases up to June 2019 were included. Results: The estimated prevalence of hMPV was 8.9% (95% CI 5.4-14.2) in different regions in Iran. Compared to the global rate, in Iran hMPV infection presented an intermediate prevalence rate. The majority of hMPV positive patients were pediatric populations with pooled prevalence of 7.6% (I² = 95%, 95% CI 3.5-15.6). Conclusion: This first comprehensive review covering researches over the last 11 years expanded our knowledge about hMPV circulating in Iran. Future large epidemiological studies are needed for the evaluation of hMPV prevalence and genotype distribution in different unanalyzed regions in Iran.

The Prevalence and Genetic Characterization of Human Metapneumovirus in Bulgaria, 2016-2019

INTRODUCTION

We investigated the prevalence of human metapneumovirus (hMPV) among patients with acute respiratory infections in Bulgaria, and performed genetic characterization of the F gene of these strains.

METHODS

Nasopharyngeal swabs collected from patients of a range of ages were tested by using real-time PCR for 12 respiratory viruses. The F gene was sequenced, and phylogenetic and amino acid analyses of the F gene/protein were performed.

RESULTS

A total of 1,842 patients were examined during a 3-year period; 1,229 patients (66.7%) were positive for at least one respiratory virus. hMPV was identified in 83 (4.5%) patient samples. Eleven (13%) of hMPV-positive patients were coinfected with another respiratory virus. The hMPV incidence rate in the 2016/2017, 2017/2018, and 2018/2019 winter seasons was 5.4, 5.4, and 3.1%, respectively. hMPV was mainly detected in specimens collected between January and May (89.2% of cases). The incidence of hMPV infection was highest (5.1%) among the youngest age-group (0-4 years), where hMPV was a causative agent in 8.1 and 4.8% of bronchiolitis and pneumonia cases, respectively. Among the patients aged ≥5 years, hMPV was detected in 2.2 and 3.2% of cases of pneumonia and central nervous system infections, respectively. Phylogenetic analysis of the F gene showed that the sequenced hMPV strains belonged to the A2b, B1, and B2 genotypes. Numerous amino acid substitutions were identified compared with the NL00/1 prototype strain.

CONCLUSION

This study revealed the significant role of hMPV as a causative agent of serious respiratory illnesses in early childhood, and also demonstrated year-to-year changes in hMPV prevalence and genetic diversity in circulating strains.

Phylogenetic analysis and circulation pattern of human metapneumovirus strains in children with acute respiratory infection in Iran, 2014–2015

Aim: The aim of the present study was to investigate the prevalence and genetic variation of the human metapneumovirus (HMPV) G gene in children less than 8 years old with acute respiratory tract infections in Iran during 2014–2015. Materials & methods: To this end, 110 nasal swabs were tested for HMPV F gene. All positive samples were tested for the full length of HMPV G gene, then sequenced and analyzed for phylogenetic grouping. Results: Six (5.45%) out of 110 samples were positive for HMPV gene. Our HMPV sequences clustered into two main clusters: A2b (five isolates) and B1 (one isolate). The dN/dS ratio showed the presence of negative selective pressure. Conclusion: A2b was the predominant genotype during the study period in southwest of Iran.

Experiments Investigating the Competitive Growth Advantage of Two Different Genotypes of Human Metapneumovirus: Implications for the Alternation of Genotype Prevalence

Human metapneumovirus (hMPV) is an important pathogen that causes upper and lower respiratory tract infections in children worldwide. hMPV has two major genotypes, hMPV-A and hMPV-B. Epidemiological studies have shown that the two hMPV genotypes alternate in predominance worldwide in recent years. Co-circulation of the two genotypes of hMPV was usually observed and there is no study about the interaction between them, such as competitive replication, which maybe the possible mechanisms for alternating prevalence of subtypes. Our present study have used two different genotypes of hMPV (genotype A: NL/1/00; B: NL/1/99) in different proportions in animal model (BALB/c mice) and cell model (Vero-E6) separately. The result showed that the competitive growth does exist in BALB/c mice, genotype B had a strong competitive advantage. However, genotype B did not cause more severe disease than non-predominant (genotype A) or mixed strains in the study, which were evaluated by the body weight, airway hyperresponsiveness and lung pathology of mouse. In cell model, competitive growth and the two genotypes alternately prevalence were observed. In summary, we confirmed that there was a competitive replication between hMPV genotype A and B, and no difference in disease severity caused by the two subtypes. This study shows a new insight to understand the alternation of hMPV genotype prevalence through genotype competition and provide experimental evidence for disease control and vaccine design.

Epidemiological and genetic characteristics of human metapneumovirus in pediatric patients across six consecutive seasons in Beijing, China

OBJECTIVES

To investigate the genetic characteristics of human metapneumovirus (hMPV) circulating among children with acute respiratory tract infections (ARTIs) in Beijing, China.

METHODS

Clinical samples were obtained from outpatients and hospitalized children with ARTIs between August 2010 and July 2016. Reverse transcription polymerase chain reaction assays were used to screen and identify hMPV, while partial glycoprotein gene sequences were used for phylogenetic analysis.

RESULTS

Among the 10 918 samples, 292 (2.7%) were positive for hMPV. Overall, the virus was more prevalent among inpatients (4.3%) than outpatients (1.2%). A biennial alternating pattern of hMPV infection was observed, with infection rates fluctuating between 1.6% and 4.0%. Most cases were detected between December and April, showing clear-cut seasonality. Sub-genotypes A2b, B1, and B2 co-circulated in winter and spring in an alternating pattern, while only one A1-positive case was observed in 2012. The seasonal peak of hMPV was slightly delayed or overlapped with that of respiratory syncytial virus and influenza virus. hMPV activity increased in the 2010-2011 and 2014-2015 seasons, when influenza activity was apparently decreased compared with other epidemic seasons.

CONCLUSIONS

This study provides information on the epidemiological and genetic characteristics of hMPV in children in Beijing, and reinforces the significance of hMPV in children with ARTIs, especially lower respiratory tract infections.

Epidemiological, clinical and genotypic features of human Metapneumovirus in patients with influenza-like illness in Senegal, 2012 to 2016

Background

Human metapneumovirus (HMPV) is a causal agent of acute respiratory infection, especially in primarily children. At the clinical level, HMPV is associated to several diseases including bronchitis, croup, pneumonia, bronchiolitis, reactive airway disease, chronic obstructive pulmonary disease and asthma exacerbations, specifically in children less than 5 years. Here, we carried out a retrospective pilot study, based on the processing of nasopharyngeal swabs, with a focus on the epidemiology and molecular characteristics of HMPV in Senegal.

Methods

This retrospective study was conducted from January 2012 to December 2016. Briefly, all outpatients presenting to healthcare sentinel sites were screened for surveillance enrollment and included if they met criteria for ILI. Naso-oropharyngeal swabs were collected from eligible participants. For viral respiratory pathogens detection, including HMPV, the Anyplex™ II RV16 Detection kit was used. A fragment of the hMPV F gene was targeted for sequencing.

Results

In total, 8209 patients with ILI were enrolled. Half of them (49.7%) were children under 5 years. Fever was the most common symptom followed by cough, and rhinitis. Three hundred eight patients were positive for HMPV (3.75%). 89 (28.9%) were detected as single infection. In co-infection cases, the most common co-infecting viruses were influenza, adenovirus and rhinovirus. HMPV detection rates in the different age groups varied significantly with the children under 5 years group accounting for 71.7% of positive patients. The temporal distribution pattern for HMPV infection showed a clear seasonal pattern with a higher activity during the rainy period (July–September). Phylogenetic analyses revealed that HMPV specimens circulating in Senegal were distributed into the two main genetic lineages, A and B. We also noted a co-circulation of both genetic lineages during the whole study period except in 2014.

Conclusion

In summary, the present study characterized the recent prevalence, seasonality and genetic diversity of HMPV in a large outpatient population presented with ILI in Senegal between 2012 and 2016. Globally our results show a clear seasonal circulation pattern of HMPV in Senegal. Our findings identified children less than 5 years as more susceptible group to HMPV infection. Molecular studies identified A2, B1 and B2 as the major genotypes circulating.

Respiratory syncytial virus, human metapneumovirus, and influenza virus infection in Bangkok, 2016-2017

Children and adults residing in densely populated urban centers around the world are at risk of seasonal influenza-like illness caused by respiratory viruses such as influenza virus, human metapneumovirus (hMPV), and respiratory syncytial virus (RSV). In a large metropolitan of Thailand’s capital city Bangkok, most respiratory infections are rarely confirmed by molecular diagnostics. We therefore examined the frequency of RSV, hMPV, and influenza virus in 8,842 patients who presented influenza-like illness and sought medical care at a large hospital in Bangkok between 2016 and 2017. Using a multiplex real-time reverse-transcription polymerase chain reaction (RT-PCR), 30.5% (2,699/8,842) of nasopharyngeal (NP) swab samples tested positive for one or more of these viruses. Influenza virus comprised 17.3% (1,528/8,842), of which the majority were influenza A/H3N2. Such infection was most prevalent among adults and the elderly. RSV was identified in 11.4% (1,011/8,842) and were mostly ON1 and BA9 genotypes. Of the hMPV-positive samples (3.6%, 318/8,842), genotypes A2, B1, and B2 were detected. A small number of individuals experienced co-infections (1.8%, 155/8,842), most commonly between RSV and influenza A/H3N2. RSV and hMPV co-infections were also found, but mainly in young children. Viral respiratory tract infection peaked locally in the rainy season (June to September). These findings support the utility of rapid nucleic acid testing of RSV, hMPV, and influenza virus in patients with ILI.

Detection of six common human paramyxoviruses in patients with acute febrile respiratory symptoms using a novel multiplex real-time RT-PCR assay

Human metapneumovirus (hMPV), respiratory syncytial virus type A (RSV‐A), RSV‐B, and human parainfluenza viruses 1, 2, and 3 (HPIV‐1, HPIV‐2, and HPIV‐3) are common respiratory paramyxoviruses. Here, we developed a two‐tube triplex one‐step real‐time reverse‐transcription polymerase chain reaction (real‐time RT‐PCR) and evaluated its performance using clinical samples. The data showed that this novel assay was 100% consistent with the monoplex real‐time RT‐PCR assay (in‐house), which was superior to the commercial routine multiplex‐ligation‐NAT‐based assay. Meanwhile, the clinical nasopharyngeal swabs of 471 patients with the acute febrile respiratory syndrome (AFRS) were analyzed using the established method. The results showed that 52 (11.7%) cases were positive for paramyxovirus. Among them, HPIVs and RSV‐A had the highest detection rate. The age and seasonal distribution of human paramyxovirus infection were analyzed. In conclusion, we developed a novel multiplex real‐time RT‐PCR assay for the rapid detection of six common human paramyxoviruses, which were dominant in patients with AFRS in Qinghai.

1.

We developed a novel multiplex real‐time RT‐PCR assay for the rapid detection of six common human paramyxoviruses for patients with AFRS in Qinghai.

2.

This method provides a new approach with a higher quality of performance (accuracy, speed, and higher sensitivity) for the detection of common respiratory paramyxoviruses in clinical specimens.

3.

The method is more specimen‐ and time‐ saving and more cost‐effective, without compromising quality, compared with monoplex real time RT PCR and commercial routine multiplex ligation‐NAT‐based RF 22.

A multiplex one-tube nested real time RT-PCR assay for simultaneous detection of respiratory syncytial virus, human rhinovirus and human metapneumovirus

BACKGROUND

Respiratory syncytial virus (RSV), human Rhinovirus (HRV) and human Metapneumo Virus (HMPV) are important viral pathogens causing acute respiratory tract infections in the hospitalized patients. Sensitive and accurate detection of RSV, HRV and HMPV is necessary for clinical diagnosis and treatment.

RESULTS

A locked nucleic acid (LNA)-based multiplex closed one-tube nested real-time RT-PCR (mOTNRT-PCR) assay was developed for simultaneous detection of RSV, HRV and HMPV. The sensitivity, specificity, reproducibility and clinical performance of mOTNRT-PCR were evaluated and compared with individual real time PCR (RT-qPCR) assay using clinical samples. The analytical sensitivity of mOTNRT-PCR assay was 5 copies/reaction for RSV, HRV and HMPV, respectively, and no cross-reaction with other common respiratory viruses was observed. The coefficients of variation (CV) of intra-assay and inter-assay were between 0.51 to 3.67%. Of 398 nasopharyngeal aspirates samples tested, 109 (27.39%), 150 (37.69%) and 44 (11.06%) were positive for RSV, HRV and HMPV, respectively, whereas 95 (23.87%), 137 (34.42%) and 38 (9.55%) were positive for RSV, HRV and HMPV, respectively, by individual RT-qPCR assay. Thirty three samples that were positive by mOTNRT-PCR but negative by RT-qPCR were confirmed as true positives by sequencing using reported traditional two-step nested PCR assay.

CONCLUSION

mOTNRT-PCR assay reveals extremely higher sensitivity than that of RT-qPCR assay for detecting RSV, HRV and HMPV in clinical settings.

Modulation of Host Immunity by the Human Metapneumovirus

Globally, as a leading agent of acute respiratory tract infections in children <5 years of age and the elderly, the human metapneumovirus (HMPV) has gained considerable attention. As inferred from studies comparing vaccinated and experimentally infected mice, the acquired immune response elicited by this pathogen fails to efficiently clear the virus from the airways, which leads to an exaggerated inflammatory response and lung damage. Furthermore, after disease resolution, there is a poor development of T and B cell immunological memory, which is believed to promote reinfections and viral spread in the community. In this article, we discuss the molecular mechanisms that shape the interactions of HMPV with host tissues that lead to pulmonary pathology and to the development of adaptive immunity that fails to protect against natural infections by this virus.

Prevalence of Human metapneumovirus infection among patients with influenza-like illness: Report from a Tertiary Care Centre, Southern India

BACKGROUND

Human metapneumovirus (HMPV), discovered in the 21st century, has emerged as an important cause of influenza-like illness in children and adults causing mild upper respiratory tract infection to severe bronchiolitis and community-associated pneumonia. The aim of this study was to determine the prevalence of HMPV in the Union Territory of Puducherry, India, as part of National Influenza Surveillance Programme.

MATERIALS AND METHODS

From November 2011 to December 2013, a total of 447 nasopharyngeal samples were collected from patients with acute respiratory infections and tested for HMPV RNA by real-time polymerase chain reaction.

RESULTS

HMPV was identified in 23/447 (5%) samples with 11/23 in the age group of 14-30 years. Most of the HMPV infections were mild with no fatalities. Two patients were co-infected with the respiratory syncytial virus and one with influenza B virus. The seasonal distribution showed increasing HMPV infection cases in rainy months except for a peak in summer of 2012. Phylogenetic analysis based on the sequences of the nucleoprotein gene of one HMPV strain showed a high degree of sequence identity with Indian strains obtained during 2006 and 2011.

CONCLUSION

This study shows that HMPV infection is more common in adults than in children. Sequence homology suggests the circulation of closely related HMPV strains within the country.

Molecular Epidemiology of Human Metapneumovirus in Riyadh Province, Saudi Arabia

Human metapneumovirus (HMPV) is an important cause of respiratory tract illness in children. Two HMPV subgroups, A and B, and four genotypes, A1, A2, B1 and B2, have been identified. Concurrent circulation of the different genotypes in yearly epidemics has been recorded globally, but not in Saudi Arabia. The current report was designed to study HMPV epidemiology in Saudi children and to analyze the genetic diversity and circulation patterns. Nasopharyngeal aspirates (n = 174) were collected from hospitalized children in Riyadh (2008-2009). The screening of samples using real-time RT-PCR identified 19 HMPV strains. The majority of the strains belonged to subgroup B, while all strains of subgroup A were members of genotype A2. In 2008, only subgroup B was recognized, whereas in 2009 both subgroups were identified to be cocirculating at similar rates. The full-length attachment (G) gene and a partial sequence of the fusion (F) gene of positive samples were sequenced. The G gene showed a high degree of genetic diversity and exhibited a variable number of positively selected sites in different lineages. In contrast, the F gene demonstrated an extensive genetic stability with a higher tendency toward purifying selection. This is the first report on HMPV genotype circulation in Saudi Arabia; however, the exact circulation kinetics requires further retrospective and prospective study.

Development of a multiplex RT-PCR for simultaneous diagnosis of human metapneumovirus (HMPV) and human respiratory syncytial virus (HRSV) from clinical specimens

Human metapneumovirus (HMPV) and human respiratory syncytial virus (HRSV) are ubiquitous respiratory viral pathogens. They belong to the family Paramyxoviridae (subfamily Pneumovirinae) and is responsible for acute respiratory tract infections in children, elderly and immunocompromised patients. We designed and tested a multiplex reverse transcriptase polymerase chain reaction (mRT-PCR) as a cost-effective alternative to real-time PCR and cell culture based detection for HMPV and HRSV. The newly developed PCR was used to screen nasal/throat swab samples from 356 patients with suspected acute respiratory infection attending the Government Medical College, Thiruvananthapuram, Kerala, India. The method was compared with a commercially available kit employing real time PCR, for its sensitivity and specificity. 53 (14.9 %) samples were positive for at least one tested pathogen by mRT-PCR. All except one among the positive samples showed similar pathogen profile when tested using real time PCR. 8 (15.1 %) among these 53 were positive for HRSVA, 33 (62.3 %) positive for HRSVB and 12 (22.6 %) were positive for HMPV. 17 (32.7 %) samples showed co-infections in them. Sensitivity and specificity of the mRT-PCR was comparable to that of the commercial kit. Our findings indicate that this newly developed mRT-PCR can be used as a cost-effective alternative for laboratory diagnosis of HMPV/HRSV infection and will significantly reduce diagnostic costs for these viruses in clinical settings.

Human metapneumovirus epidemiological and evolutionary patterns in Coastal Kenya, 2007-11

BACKGROUND

Human metapneumovirus (HMPV) is an important global cause of severe acute respiratory infections in young children and the elderly. The epidemiology of HMPV in sub-Saharan Africa is poorly described and factors that allow its recurrent epidemics in communities not understood.

METHODS

We undertook paediatric inpatient surveillance for HMPV in Kilifi County Hospital (KCH) of Coastal Kenya between 2007 and 2011. Nasopharyngeal samples collected from children aged 1 day-59 months admitted with severe or very severe pneumonia, were tested for HMPV using real-time polymerase chain reaction (RT-PCR). Partial nucleotide sequences of the attachment (G) and fusion (F) surface proteins of positive samples were determined and phylogenetically analyzed.

RESULTS

HMPV was detected in 4.8 % (160/3320) of children [73.8 % (118/160) of these less than one year of age], ranging between 2.9 and 8.8 % each year over the 5 years of study. HMPV infections were seasonal in occurrence, with cases predominant in the months of November through April. These months frequently coincided with low rainfall, high temperature and low relative humidity in the location. Phylogenetic analysis of partial F and G sequences revealed three subgroups of HMPV, A2 (74 %, 91/123), B1 (3.2 %, 4/123) and B2 (22.8 %, 28/123) in circulation, with subgroup A2 predominant in majority of the epidemic seasons. Comparison of G sequences (local and global) provided a greater phylogenetic resolution over comparison of F sequences and indicated presence of probable multiple G antigenic variants within the subgroups due to differences in amino acid sequence, encoded protein length and glycosylation patterns.

CONCLUSION

The present study reveals HMPV is an important seasonal contributor to respiratory disease hospitalization in coastal Kenya, with an evolutionary pattern closely relating to that of respiratory syncytial virus.

Genetic diversity, seasonality and transmission network of human metapneumovirus: identification of a unique sub-lineage of the fusion and attachment genes

Human metapneumovirus (HMPV) is an important viral respiratory pathogen worldwide. Current knowledge regarding the genetic diversity, seasonality and transmission dynamics of HMPV among adults and children living in tropical climate remains limited. HMPV prevailed at 2.2% (n = 86/3,935) among individuals presented with acute respiratory tract infections in Kuala Lumpur, Malaysia between 2012 and 2014. Seasonal peaks were observed during the northeast monsoon season (November-April) and correlated with higher relative humidity and number of rainy days (P < 0.05). Phylogenetic analysis of the fusion and attachment genes identified the co-circulation of three known HMPV sub-lineages, A2b and B1 (30.2% each, 26/86) and B2 (20.9%, 18/86), with genotype shift from sub-lineage B1 to A2b observed in 2013. Interestingly, a previously unrecognized sub-lineage of A2 was identified in 18.6% (16/86) of the population. Using a custom script for network construction based on the TN93 pairwise genetic distance, we identified up to nine HMPV transmission clusters circulating as multiple sub-epidemics. Although no apparent major outbreak was observed, the increased frequency of transmission clusters (dyads) during seasonal peaks suggests the potential roles of transmission clusters in driving the spread of HMPV. Our findings provide essential information for therapeutic research, prevention strategies, and disease outbreak monitoring of HMPV.

Genetic diversity of human rhinoviruses in Cambodia during a three-year period reveals novel genetic types

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Five novel genotypes are identified based on VP1 sequences.

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Co-infections with other viruses is demonstrated.

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The genome of rhinoviruses is saturated.

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A novel classification system considering amino acid sequences should be developed.

Acute respiratory viral infections are a major cause of morbidity during early childhood in developing countries. Human rhinoviruses are the most frequent cause of upper respiratory tract infections in humans, which can range in severity from asymptomatic to clinically severe disease. In this study we collected 4170 nasopharyngeal swabs from patients hospitalised with influenza-like illness in two Cambodian provincial hospitals between 2007 and 2010. Samples were screened for 18 respiratory viruses using 5 multiplex PCRs. A total of 11.2% of samples tested positive for human rhinoviruses (HRV). VP4/2 and VP1 regions were amplified and sequenced to study the distribution of rhinoviruses genotypes and species in Cambodia during this three-year period. Five novel genotypes, 2 species A, 2 species B and 1 species C were identified based on VP1 sequences. Co-infections with other viruses were demonstrated.

Phylogenetic analysis of human metapneumovirus detected in hospitalized patients in Kuwait during the years 2009-2011

BACKGROUND

Human metapneumovirus (hMPV) is an important cause of both upper and lower respiratory tract infections (RTIs) in all age groups. Children, elderly, and immunocompromised individuals are the most affected groups. HMPV infection accounts for 5% of hospitalized patients with respiratory tract infections in Kuwait. It is mostly detected among infants and elderly age groups, and both hMPV genotypes A and B circulate in Kuwait.

METHODS

In this study, the genetic diversity of detected hMPV was evaluated, and a phylogenetic analysis based on partial nucleotide and amino acid sequences of the G gene was performed for hMPV detected among hospitalized patients with RTIs.

RESULTS

Our results showed that 62% of hMPV sequences belonged to the A genotype and 38% to the B genotype. A2b and B2 subtypes were detected and circulated during the study period, whereas A1 and B1 subtypes were not detected. Based on nucleotide sequences of the G gene, most of hMPV strains (57%) were clustered with Indian strains, followed by Greek strains (24%) and Canadian strains (14%). One strain (5%) clustered within the B genotype but had different branches than B1 and B2 branches.

CONCLUSION

Our data showed the co-circulation of hMPV genotypes A2b and B2 in Kuwait with genetic diversity suggestive of evolution through negative selection.

Identification of new respiratory viruses in the new millennium

The rapid advancement of molecular tools in the past 15 years has allowed for the retrospective discovery of several new respiratory viruses as well as the characterization of novel emergent strains. The inability to characterize the etiological origins of respiratory conditions, particularly in children, led several researchers to pursue the discovery of the underlying etiology of disease. In 2001, this led to the discovery of human metapneumovirus (hMPV) and soon following that the outbreak of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) promoted an increased interest in coronavirology and the latter discovery of human coronavirus (HCoV) NL63 and HCoV-HKU1. Human bocavirus, with its four separate lineages, discovered in 2005, has been linked to acute respiratory tract infections and gastrointestinal complications. Middle East Respiratory Syndrome coronavirus (MERS-CoV) represents the most recent outbreak of a completely novel respiratory virus, which occurred in Saudi Arabia in 2012 and presents a significant threat to human health. This review will detail the most current clinical and epidemiological findings to all respiratory viruses discovered since 2001.

Knowledge translation: a case study on pneumonia research and clinical guidelines in a low- income country

BACKGROUND

The process and effectiveness of knowledge translation (KT) interventions targeting policymakers are rarely reported. In Cambodia, a low-income country (LIC), an intervention aiming to provide evidence-based knowledge on pneumonia to health authorities was developed to help update pediatric and adult national clinical guidelines. Through a case study, we assessed the effectiveness of this KT intervention, with the goal of identifying the barriers to KT and suggest strategies to facilitate KT in similar settings.

METHODS

An extensive search for all relevant sources of data documenting the processes of updating adult and pediatric pneumonia guidelines was done. Documents included among others, reports, meeting minutes, and email correspondences. The study was conducted in successive phases: an appraisal of the content of both adult and pediatric pneumonia guidelines; an appraisal of the quality of guidelines by independent experts, using the AGREE-II instrument; a description and modeling of the KT process within the guidelines updating system, using the Unified Modeling Language (UML) tools 2.2; and the listing of the barriers and facilitators to KT we identified during the study.

RESULTS

The first appraisal showed that the integration of the KT key messages in pediatric and adult guidelines varied with a better efficiency in the pediatric guidelines. The overall AGREE-II quality assessments scored 37% and 44% for adult and pediatric guidelines, respectively. Scores were lowest for the domains of 'rigor of development' and 'editorial independence.' The UML analysis highlighted that time frames and constraints of the involved stakeholders greatly differed and that there were several missed opportunities to translate on evidence into the adult pneumonia guideline. Seventeen facilitating factors and 18 potential barriers to KT were identified. Main barriers were related to the absence of a clear mandate from the Ministry of Health for the researchers and to a lack of synchronization between knowledge production and policy-making.

CONCLUSIONS

Study findings suggest that stakeholders, both researchers and policy makers planning to update clinical guidelines in LIC may need methodological support to overcome the expected barriers.

Prevalence and molecular characterization of human metapneumovirus in influenza a negative sample in Thailand

Background

Human metapneumovirus (hMPV) causes respiratory tract infection in influenza‐like illness. The role of hMPV infections in all age groups in Thailand has not yet been investigated. Thus, the objective of this study was to determine prevalence of hMPV infection in all age groups in Thailand during 2011.

Methods

A total of 1,184 nasopharyngeal washes were collected from hospitalized patients and sent to the Department of Microbiology, Siriraj Hospital, for influenza A virus detection. Real‐time polymerase chain reaction (PCR) was used to detect hMPV infection. Partially, F gene from hMPV positive samples were sequenced and used for genotyping by phylogenetic tree analysis.

Results

The prevalence of hMPV for all age groups was 6.3%. The highest prevalence of hMPV infection was in children aged <2 years. Of 71 hMPV‐positive patients, three (4.2%) were coinfected with respiratory syncytial virus (RSV), two with rhinovirus (2.8%), one with coronavirus (1.4%), and one with RSV and adenovirus (1.4%). Phylogenetic analysis of F gene revealed that 96.8% of hMPV detected was subgenotype B1, 1.6% was sublineage A2a, and 1.6% was A2b. Genetic variation of F gene was much conserved.

Conclusion

We demonstrated the prevalence of hMPV subgenotype B1 circulating in Thailand during 2011.

Molecular analysis of human metapneumovirus detected in patients with lower respiratory tract infection in upper egypt

Introduction. Since 2001, when Human metapneumovirus (HMPV) was isolated in the Netherlands, the virus has been detected in several continents. Although reports have confirmed the prevalence of HMPV worldwide, data from Egypt remain limited. HMPV plays an important role in respiratory tract infections in individuals of all ages particularly in children. This study was aimed at estimating the prevalence of HMPV in patients with community-acquired lower respiratory infection in Upper Egypt and characterizing the circulating Egyptian HMPV strains for the first time. Materials and Methods. From 2005 to 2008, respiratory samples from 520 patients were analyzed for the presence of HMPV by real-time RT-PCR. Molecular and phylogenetic analyses were performed on partial fusion gene sequences of HMPV-positive patients. Results. HMPV-positive patients were detected in 2007-2008. The overall infection rate was 4%, while 57% of the patients were children. Sequence analysis demonstrated circulation of subgroup B viruses with predominance of lineage B2. Nucleotide sequence identity within lineage B1 was 98.8%–99.7% and higher than that in lineage B2 (94.3%–100%). Three new amino acid substitutions (T223N, R229K, and D280N) of lineage B2 were observed. Conclusion. HMPV is a major viral pathogen in the Egyptian population especially in children. During 2007-2008, predominantly HMPV B2 circulated in Upper Egypt.

Genetic variability of human metapneumo- and bocaviruses in children with respiratory tract infections

OBJECTIVES

The genotypic analysis of human metapneumo-(HMPV) and boca-(HBoV) viruses circulating in Greece and their comparison to reference and other clinical strains.

DESIGN

Genetic analysis of representative strains over three consecutive winter seasons of the years 2005-2008.

SETTING

Representative positive specimens for HMPV and HBoV from paediatric patients of healthcare units and hospitals in Southern Greece with influenza-like illness or other respiratory tract infections.

SAMPLE

Seven to ten positive specimens for either HMPV or HBoV from each winter period. In total, 24 specimens positive for HMPV and 26 for HBoV, respectively.

MAIN OUTCOME MEASURES

Sequence diversity of HMPV and HBoV strains by sequencing the complete G and VP1/VP2 genes, respectively.

RESULTS

In total, 24 HMPV strains were found to have a 92-100% nucleotide and a 85.9-100% amino acid identity. Phylogenetic analysis based on the number of amino acid differences, revealed circulation of 4 different subclusters belonging to genetic lineage B2. Similarly, analysis of 26 HBoV strains indicated that 22 clustered within genotype St2, 2 into genotype St1 and the remaining 2 formed a third cluster derived from potential recombination between different St1 genotype strains. St2 HBoV genotype was observed throughout the whole observation period whereas St1 only during the second and the third winter period. Higher levels of heterogeneity were observed between HMPV compared to HBoV strains.

CONCLUSIONS

Phylogenetic analysis revealed circulation of one single lineage (B2) for HMPV viruses and predominance of St2 genotype for HBoV viruses. A possible recombination between St1 genotype strains of HBoV was observed.

Molecular epidemiology of respiratory viruses in virus-induced asthma

Acute respiratory illness (ARI) due to various viruses is not only the most common cause of upper respiratory infection in humans but is also a major cause of morbidity and mortality, leading to diseases such as bronchiolitis and pneumonia. Previous studies have shown that respiratory syncytial virus (RSV), human rhinovirus (HRV), human metapneumovirus (HMPV), human parainfluenza virus (HPIV), and human enterovirus infections may be associated with virus-induced asthma. For example, it has been suggested that HRV infection is detected in the acute exacerbation of asthma and infection is prolonged. Thus it is believed that the main etiological cause of asthma is ARI viruses. Furthermore, the number of asthma patients in most industrial countries has greatly increased, resulting in a morbidity rate of around 10-15% of the population. However, the relationships between viral infections, host immune response, and host factors in the pathophysiology of asthma remain unclear. To gain a better understanding of the epidemiology of virus-induced asthma, it is important to assess both the characteristics of the viruses and the host defense mechanisms. Molecular epidemiology enables us to understand the pathogenesis of microorganisms by identifying specific pathways, molecules, and genes that influence the risk of developing a disease. However, the epidemiology of various respiratory viruses associated with virus-induced asthma is not fully understood. Therefore, in this article, we review molecular epidemiological studies of RSV, HRV, HPIV, and HMPV infection associated with virus-induced asthma.

Acute lower respiratory infections on lung sequelae in Cambodia, a neglected disease in highly tuberculosis-endemic country

Background

Little is known about post-infectious pulmonary sequelae in countries like Cambodia where tuberculosis is hyper-endemic and childhood pulmonary infections are highly frequent. We describe the characteristics of hospitalized Cambodian patients presenting with community-acquired acute lower respiratory infections (ALRI) on post-infectious pulmonary sequelae (ALRIPS).

Methods

Between 2007 and 2010, inpatients ≥15 years with ALRI were prospectively recruited. Clinical, biological, radiological and microbiological data were collected. Chest radiographs were re-interpreted by experts to compare patients with ALRIPS, on previously healthy lungs (ALRIHL) and active pulmonary tuberculosis (TB). Patients without chest radiograph abnormality or with abnormality suggestive as other chronic respiratory diseases were excluded from this analysis.

Results

Among the 2351 inpatients with community-acquired ALRI, 1800 were eligible: 426 (18%) ALRIPS, 878 (37%) ALRIHL and 496 (21%) TB. ALRIPS patients had less frequent fever than other ALRI (p < 0.001) and more productive cough than ALRIHL (p < 0.001). Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa accounted for 83% of ALRIPS group positive cultures. H. influenzae and P. aeruginosa were significantly associated with ALRIPS compared with ALRIHL. Treatment was appropriate in 58% of ALRIPS patients. Finally, 79% of ALRIPS were not recognized by local clinicians. In-hospital mortality was low (1%) but probably underestimated in the ALRIPS group.

Conclusion

ALRIPS remains often misdiagnosed as TB with inappropriate treatment in low-income countries. Better-targeted training programs would help reduce the morbidity burden and financial costs.

Phylogenetic and phylodynamic analyses of human metapneumovirus in Buenos Aires (Argentina) for a three-year period (2009-2011)

Human metapneumovirus, which belongs to the Paramyxoviridae family and has been classified as a member of the Pneumovirus genus, is genetically and clinically similar to other family members such as human respiratory syncytial virus. A total of 1146 nasopharyngeal aspirates from pediatric patients with moderate and severe acute lower respiratory tract infections, hospitalized at the Ricardo Gutierrez Childreńs Hospital (Buenos Aires, Argentina), were tested by real time RT-PCR for human metapneumovirus. Results showed that 168 (14.65%) were positive. Thirty-six of these 168 samples were randomly selected to characterize positive cases molecularly. The phylogenetic analysis of the sequences of the G and F genes showed that genotypes A2 and B2 cocirculated during 2009 and 2010 and that only genotype A2 circulated in 2011 in Argentina. Genotype A2 prevailed during the study period, a fact supported by a higher effective population size (Neτ) and higher diversity as compared to that of genotype B2 (10.9% (SE 1.3%) vs. 1.7% (SE 0.4%), respectively). The phylogeographic analysis of the G protein gene sequences showed that this virus has no geographical restrictions and can travel globally harbored in hosts. The selection pressure analysis of the F protein showed that although this protein has regions with polymorphisms, it has vast structural and functional constraints. In addition, the predicted B-linear epitopes and the sites recognized by previously described monoclonal antibodies were conserved in all Argentine sequences. This points out this protein as a potential candidate to be the target of future humanized antibodies or vaccines.

Human metapneumovirus-associated hospital admissions over five consecutive epidemic seasons: evidence for alternating circulation of different genotypes

Human metapneumovirus (hMPV) is a pathogen of the respiratory tract with a worldwide distribution. The purpose of this study was to identify hMPV as the cause of acute respiratory diseases in children admitted at Spedali Civili, a public hospital in Brescia, Italy. Eight hundred forty‐six nasopharyngeal aspirate samples negative for the presence of other common respiratory viruses were tested for the presence of hMPV RNA by reverse transcription‐polymerase chain reaction. Of the 846 samples, 79 (9.3%) were positive for hMPV. Polymerase chain reaction products, obtained by amplification of the partial nucleotide sequence of gene F, were sequenced and compared with sequences deposited in GenBank. All four hMPV subtypes were identified, including the proposed subtype A2 sublineages “A” and “B”. In successive epidemic seasons, large outbreaks of hMPV alternated with small outbreaks in a biannual pattern. This local study provides further evidence that hMPV infection should be considered as a reason for hospital admission for acute respiratory disease in children. J. Med. Virol. 84:511–516, 2012. © 2011 Wiley Periodicals, Inc.

Viral infections of the lower respiratory tract

Lower respiratory tract infections (LRTIs) are a global burden to public health and are frequently caused by respiratory viruses. Advances in molecular diagnostic techniques have allowed the identification of previously undetected viral pathogens and have improved our understanding of respiratory virus infections. Here we review the epidemiological and clinical characteristics of recently identified viruses including human metapneumovirus, human coronaviruses NL63 and HKU1, human rhinovirus C, bocavirus, WU and KI polyomaviruses, and parechovirus. The roles of these viruses in LRTIs in children and adults are discussed.

Human bocavirus amongst an all-ages population hospitalised with acute lower respiratory infections in Cambodia

BACKGROUND

Human bocavirus (HBoV) is a novel parvovirus that is associated with respiratory and gastrointestinal tract disease.

OBJECTIVES

To investigate the prevalence and genetic diversity of HBoV amongst hospitalized patients with acute lower respiratory infection (ALRI) in Cambodia.

STUDY DESIGN

  Samples were collected from 2773 patients of all ages hospitalised with symptoms of ALRI between 2007 and 2009. All samples were screened by multiplex RT-PCR/PCR for 18 respiratory viruses. All samples positive for HBoV were sequenced and included in this study.

RESULTS

Of the samples tested, 43 (1·5%) were positive for HBoV. The incidence of HBoV did not vary between the consecutive seasons investigated, and HBoV infections were detected year-round. The incidence of HBoV infection was highest in patients aged < 2 years, with pneumonia or bronchopneumonia the most common clinical diagnosis, regardless of age. A total of 19 patients (44%) were co-infected with HBoV and an additional respiratory pathogen. All isolates were classified as HBoV type 1 (HBoV-1). High conservation between Cambodian NP1 and V1V2 gene sequences was observed.

CONCLUSIONS

Human bocavirus infection can result in serious illness, however is frequently detected in the context of viral co-infection. Specific studies are required to further understand the true pathogenesis of HBoV in the context of severe respiratory illness.

Increase human metapneumovirus mediated morbidity following pandemic influenza infection

Human metapneumovirus (hMPV) is a recently discovered respiratory pathogen, infecting mainly young children. The infected patients suffer from influenza like symptoms (ILS). In Israel the virus is mainly circulating in February to March. Here we report on an increased rate of hMPV infection in the winter season of 2009–10. The 2009–10 infection had several unique characteristics when compared to previous seasons; it started around January and a large number of infants were infected by the virus. Genetic analysis based on the viral L and F genes of hMPV showed that only subtypes A2 and B2 circulated in Israel. Additionally, we have identified a novel variant of hMPV within subgroup A2b, which subdivide it into A2b1 and A2b2. Finally, we showed that the hMPV infection was detected in the country soon after the infection with the pandemic influenza virus had declined, that infection with the pandemic influenza virus was dominant and that it interfered with the infection of other respiratory viruses. Thus, we suggest that the unusual increase in hMPV infection observed in 2009–10 was due to the appearance of the pandemic influenza virus in the winter season prior to 2009–10.

Human Metapneumovirus: lessons learned over the first decade

It has been 10 years since human metapneumovirus (HMPV) was identified as a causative agent of respiratory illness in humans. Since then, numerous studies have contributed to a substantial body of knowledge on many aspects of HMPV. This review summarizes our current knowledge on HMPV, HMPV disease pathogenesis, and disease intervention strategies and identifies a number of areas with key questions to be addressed in the future.

Prevalence of human metapneumovirus in adults with acute respiratory tract infection in Beijing, China

Objective

To evaluate the prevalence and clinical manifestations of human metapneumovirus (hMPV) in immunocompetent Chinese adults with acute respiratory tract infections (ARTIs).

Methods

A reverse transcription PCR (RT-PCR) assay targeting the P gene was developed in this study and used to detect hMPV in nasal and throat swabs collected from 2936 immunocompetent adult patients with ARTIs in Beijing, China between July 2008 and June 2010.

Results

Among the 2936 patients studied, 49 (1.7%) were positive for hMPV, of whom 14 (28.6%) were positive for hMPV_A2b, 19 (38.8%) for hMPV_B1, and 16 (32.6%) for hMPV_B2. hMPV_A1 was not detected. An average detection rate of 6.6% was observed in the peak months of the two epidemic seasons studied. The hMPV prevalence was higher in the sampled elderly (>65 years, 3.2%) than in middle aged adults (25–65 years; 2.0%) and teenagers (14–25 years; 0.9%). During the study period, hMPV infections showed a biennial rhythm of seasonality, peaking from November to March in 2008/09 and from March to June in 2010.

Conclusion

hMPV infection plays an important role in immunocompetent adults in its epidemic season. The demographic and clinical data presented in this study improves our understanding of the pathogenesis and clinical burden of hMPV infection in adults.

A study of the genetic variability of human respiratory syncytial virus (HRSV) in Cambodia reveals the existence of a new HRSV group B genotype

Human respiratory syncytial virus (HRSV) is the leading cause of hospitalization of children aged <5 years due to respiratory illness in industrialized countries, and pneumonia is the leading cause of mortality among children aged <5 years worldwide. Although HRSV was first identified in 1956, a preventative vaccine has yet to be developed. Here we report the results of the first study to investigate the circulation and genetic diversity of HRSV in Cambodia among an all-ages population over 5 consecutive years. The incidences of HRSV infection among all-ages outpatient and hospitalized populations were equivalent, at 9.5% and 8.2%, respectively. Infection was most prevalent among children aged <5 years, with bronchiolitis being the most frequently observed clinical syndrome in the same age group. Circulation of HRSV was seasonal, typically coinciding with the rainy season between July and November annually. Strains belonging to HRSV groups A and B were detected with equivalent frequencies; however, we observed a potentially biennial shift in the predominant circulating HRSV genotype. The majority of HRSV group B strains belonged to the recently described BA genotype, with the exception of 10 strains classified as belonging to a novel HRSV group B genotype, SAB4, first reported here.

New respiratory viruses and the elderly

The diagnostics of respiratory viral infections has improved markedly during the last 15 years with the development of PCR techniques. Since 1997, several new respiratory viruses and their subgroups have been discovered: influenza A viruses H5N1 and H1N1, human metapneumovirus, coronaviruses SARS, NL63 and HKU1, human bocavirus, human rhinoviruses C and D and potential respiratory pathogens, the KI and WU polyomaviruses and the torque teno virus. The detection of previously known viruses has also improved. Currently, a viral cause of respiratory illness is almost exclusively identifiable in children, but in the elderly, the detection rates of a viral etiology are below 40%, and this holds also true for exacerbations of chronic respiratory illnesses. The new viruses cause respiratory symptoms like the common cold, cough, bronchitis, bronchiolitis, exacerbations of asthma and chronic obstructive pulmonary disease and pneumonia. Acute respiratory failure may occur. These viruses are distributed throughout the globe and affect people of all ages. Data regarding these viruses and the elderly are scarce. This review introduces these new viruses and reviews their clinical significance, especially with regard to the elderly population.