Co-circulating genetically divergent A2 human metapneumovirus strains among children in southern Taiwan

Clinical features and genomic characteristics of post-pandemic human metapneumovirus infections in hospitalized Taiwanese children

OBJECTS

Human metapneumovirus (HMPV) is a well-recognized respiratory viral pathogen and contributes to significant disease burden among children and high-risk populations. This study describes the epidemiology, clinical features and circulating genotypes of a post-pandemic HMPV outbreak in Taiwan, 2023.

METHODS

Hospitalized children with HMPV infection confirmed by molecular diagnostics at two hospitals between January and June 2023 were enrolled in this study. Some nasal swabs were obtained from enrolled patients and sent for HMPV genotype sequencing. Medical information was retrieved and analyzed retrospectively.

RESULTS

The HMPV cases were first identified in February and peaked in May and June. A total of 69 HMPV cases were identified in this study (22.5 %, 69/306). The median age of infected cases was 43 months, and 34 were male (49.3 %). Half of the cases (38, 55.1 %) were diagnosed with bronchopneumonia or pneumonia. Forty patients received bronchodilator therapy (60 %), and 36 were treated with antibiotics (52.2 %). Phylogenetic analysis indicated lineages A2.2.2 and B2 were predominant genotypes for this outbreak. In addition, 73.3 % of HMPV-A strains were confirmed as the A2.2.2 with a 111 nt duplication variant.

CONCLUSION

HMPV lineage A2.2.2 111nt-dup and B2 were responsible for the 2023 HMPV outbreak in Taiwan. A long-term nationwide HMPV surveillance system is mandatory in Taiwan.

Epidemiology of human metapneumovirus in Taiwan from 2013 to 2023

Human metapneumovirus (HMPV) is a member of the genus Metapneumovirus in the family Pneumoviridae of the order Mononegavirales that can cause upper and lower respiratory tract disease. This retrospective study describes the epidemiology of hMPV based on community viral surveillance results from sentinel sites across Taiwan from 2013 to 2023. A total of 114 hMPV strains were isolated and analyzed to assess viral evolution through sequencing of their fusion protein genes. This study revealed that hMPV cases occur almost year-round in Taiwan, with a peak occurring during spring (March to May). Of the 114 infected patients, 68.4% were children under 4 years old. The geographical distribution of hMPV positivity was highest in Penghu County, followed by Changhua County and Hsinchu County. The clinical symptoms of hMPV infection are nonspecific, with fever (56.1%), cough (44.7%), rhinorrhea (21.1%), and sore throat (14.9%) being the most common. However, a few patients also developed severe central nervous system symptoms (1.8%) or dyspnea (0.9%). Phylogenetic analysis revealed genetic diversity among the 114 isolated hMPV strains, with the A2 lineage (57.9%) being the most frequently observed, followed by the B2 lineage (33.3%), in the Taiwanese community from 2013 to 2023. In conclusion, hMPV causes a serious acute respiratory disease in Taiwan that should not be neglected. Further epidemiological surveillance and investigations of the clinical characteristics of hMPV should be performed continually for prevention and control of this virus.

Phylogenetic variability of Human Metapneumovirus in patients with acute respiratory infections in Cameroon, 2011-2014

BACKGROUND

Identified in 2001, Human Metapneumovirus (HMPV) is a Pneumovirus associated with acute lower and upper respiratory infections in all age groups and especially in newborns, elderly and immunocompromised subjects. Data are still limited in sub-Saharan African countries genetic characterization of this respiratory virus. This study reports the genetic variability of HMPV strains in Cameroonian children for 3 consecutive epidemic seasons (September 2011-October 2014).

METHODS

A prospective surveillance was conducted to identify inpatient and outpatient children less than 15 years with respiratory symptoms ≤5 days. The nasopharyngeal samples were tested for HMPV using a multiplex polymerase chain reaction. Viral distribution and demographic data were analyzed statistically. Positive samples for HMPV were amplified by semi-nested polymerize chain reaction and then partially sequenced at the G gene. Phylogenetic analyzes were performed on the partial nucleotide and protein sequences of the G gene.

RESULTS

From September 2011 to October 2014, 822 children under 15 years were enrolled in the study. HMPV was identified in each of 3.9% (32/822) of children. HMPV were detected throughout the year. HMPV-A (73.3%; 11/15) was predominant compared to HMPV-B (26.7; 4/15). Cameroonian HMPV strains are grouped among the members of genotype A2b (for HMPV-A), B1 and B2 (for HMPV-B).

CONCLUSION

This study suggests that about 4% of ARI recorded in children in Cameroon are caused by HMPV. The present study is also the first report on the genetic variability of the G gene of HMPV strains in the region. Although this work partially fills gaps for some information, additional studies are required to clarify the molecular epidemiology and evolutionary pattern of HMPV in sub-Saharan Africa in general and more particularly in Cameroon.

A review on epidemiology and impact of human metapneumovirus infections in children using TIAB search strategy on PubMed and PubMed Central articles

Acute respiratory tract infections (ARTI) contribute to morbidity and mortality in children globally. Viruses including human metapneumovirus (hMPV) account for most ARTIs. The virus causes upper and lower respiratory tract infections mostly in young children and contributes to hospitalization of individuals with asthma,chronic obstructive pulmonary diseases and cancer. Moreover, hMPV pauses a considerable socio-economic impact creating a substantial disease burden wherever it has been studied, although hMPV testing is relatively new in many countries. We aimed to comprehensively analyze the epidemiological aspects including prevalence, disease burden and seasonality of hMPV infections in children in the world. We acquired published data extracted from PubMed and PubMed Central articles using the title and abstract (TIAB)search strategy for the major key words on hMPV infections from 9/54 African, 11/35 American, 20/50 Asian, 2/14 Australian/Oceanian and 20/51 European countries. According to the findings of this review, the prevalence of hMPV infection ranges from 1.1 to 86% in children of less than 5 years of age globally. Presence of many hMPV genotypes (A1, A2, B1, B2) and sub-genotypes (A2a, A2b, A2c, B2a, B2b) suggests a rapid evolution of the virus with limited influence by time and geography. hMPV infection mostly affects children between 2 to 5 years of age. The virus is active throughout the year in the tropics and epidemics occur during the winter and spring in temperate climates, contributing to a substantial disease burden globally.

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 epidemiology of human metapneumovirus from 2009 to 2011 in Okinawa, Japan

To clarify the molecular epidemiology of human metapneumovirus (HMPV) in Okinawa Prefecture, located in a subtropical region of Japan, we performed genetic analysis of the F gene in HMPV from patients with acute respiratory infection from January 2009 to December 2011. HMPV was detected in 18 of 485 throat swabs (3.7%). Phylogenetic analysis showed that 17 strains belonged to subgroup A2 and 1 strain belonged to subgroup B1. We did not observe seasonal prevalence of HMPV during the investigation period. A high level of sequence identity was observed in the strains belonging to subgroup A2 (>95%), and no amino acid substitution was found compared with other strains detected in Japan and other countries. The pairwise distance values among the present strains belonging to subgroup A2 were short. Our results suggest that the predominant HMPV strains belonging to A2 are highly homologous and seasonal epidemics were not seen in Okinawa during the investigation period.

Human metapneumovirus associated with community-acquired pneumonia in children in Beijing, China

Community‐acquired pneumonia is a major cause of morbidity and mortality in children worldwide. However, few studies have been conducted on the infection of human metapneumovirus (hMPV) associated with pediatric community‐acquired pneumonia in China. Nasopharyngeal aspirates were collected between July 2008 and June 2010 from 1,028 children, aged ≤16.5 years, who were diagnosed with community‐acquired pneumonia in Beijing, China. Reverse‐transcriptase polymerase chain reaction was used to screen the samples for hMPV and common respiratory viruses. hMPV was detected in 6.3% of the patients with community‐acquired pneumonia. This detection rate is the third highest for a respiratory virus in children with community‐acquired pneumonia, after that of rhinovirus (30.9%) and respiratory syncytial virus (30.7%). The detection rate of hMPV in 2008/2009 (42/540, 7.8%) was significantly higher than in 2009/2010 (23/488, 4.7%; χ² = 4.065, P = 0.044). The hMPV subtypes A2, B1, and B2 were found to co‐circulate, with A2 being most prevalent. These results indicate that hMPV plays a substantial role in pediatric community‐acquired pneumonia in China. Overall, these findings provide a better understanding of the epidemiological and clinical features of hMPV infections. J. Med. Virol. 85:138–143, 2012. © 2012 Wiley Periodicals, Inc.

Clinical features of different genotypes/genogroups of human metapneumovirus in hospitalized children

BACKGROUND/PURPOSE(S)

To explore the clinical features of different human metapneumovirus (hMPV) genotypes/genogroups in hospitalized children.

METHODS

From January 2005 to April 2010, 3313 children's respiratory specimens sent for the detection of respiratory syncytial virus antigen were also tested for hMPV by real time-polymerase chain reaction. Demographics, clinical presentations, and laboratory findings of patients infected with different genotypes/genogroups of hMPV were compared.

RESULTS

A total of 725 samples were positive for hMPV (positive rate, 23%). The F gene was sequenced for 279 isolates; of these, genotype A was identified in 51% (A1, 6.1%; A2, 45%) and genotype B in 49% (B1, 19%; B2, 30%). Medical records of 152 hospitalized children were reviewed. Co-infection with other pathogens was 25.7% (39/152). Excluding co-pathogens other than respiratory syncytial virus, a total of 124 children were analyzed. The most common symptoms included cough, fever, rhinorrhea, wheezing and respiratory distress with accessory muscle usage. The main diagnosis was bronchiolitis. The most common chest radiographic findings were increased perihilar infiltrates. No significant difference was found in terms of demographics, clinical manifestations, and laboratory findings among the children infected with different serogroups of hMPV.

CONCLUSION

hMPV accounted for a substantial proportion of hospitalized children with lower respiratory tract infection with a high co-infection rate. The A2 subgroup was the most frequently observed, followed by B2. No significant difference was found among patients infected with different genotypes/genogroups of hMPV in terms of clinical manifestations.

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.

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.

Co-circulation of genetically distinct human metapneumovirus and human bocavirus strains in young children with respiratory tract infections in Italy

The discovery of human Metapneumovirus (hMPV) and human Bocavirus (hBoV) identified the etiological causes of several cases of acute respiratory tract infections in children. This report describes the molecular epidemiology of hMPV and hBoV infections observed following viral surveillance of children hospitalized for acute respiratory tract infections in Milan, Italy. Pharyngeal swabs were collected from 240 children ≤3 years of age (130 males, 110 females; median age, 5.0 months; IQR, 2.0–12.5 months) and tested for respiratory viruses, including hMPV and hBoV, by molecular methods. hMPV‐RNA and hBoV‐DNA positive samples were characterized molecularly and a phylogenetical analysis was performed. PCR analysis identified 131/240 (54.6%) samples positive for at least one virus. The frequency of hMPV and hBoV infections was similar (8.3% and 12.1%, respectively). Both infections were associated with lower respiratory tract infections: hMPV was present as a single infectious agent in 7.2% of children with bronchiolitis, hBoV was associated with 18.5% of pediatric pneumonias and identified frequently as a single etiological agent. Genetically distinct hMPV and hBoV strains were identified in children examined with respiratory tract infections. Phylogenetic analysis showed an increased prevalence of hMPV genotype A (A2b sublineage) compared to genotype B (80% vs. 20%, respectively) and of the hBoV genotype St2 compared to genotype St1 (71.4% vs. 28.6%, respectively). Interestingly, a shift in hMPV infections resulting from A2 strains has been observed in recent years. In addition, the occurrence of recombination events between two hBoV strains with a breakpoint located in the VP1/VP2 region was identified. J. Med. Virol. 83:156–164, 2011. © 2010 Wiley‐Liss, Inc.

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

First identified in 2001, human metapneumovirus (HMPV) is a novel pathogen and causative agent of acute respiratory tract infection. Re-infection with HMPV is common, and currently there is no available vaccine against HMPV infection. Two genotypes of HMPV have been identified, A and B, both of which can be divided further into at least two distinct sub-genotypes. Here we report the results of the first study to investigate the genetic variability of HMPV strains circulating within Cambodia. The overall incidence of HMPV infection amongst an all-ages population of patients hospitalised with ALRI in Cambodia during 3 consecutive years, between 2007 and 2009, was 1.7%. The incidence of HMPV infection was highest amongst children less than 5 years of age, with pneumonia or bronchopneumonia the most frequent clinical diagnoses across all age groups. The incidence of HMPV infection varied annually. As anticipated, genetic diversity was low amongst the conserved F gene sequences but very high amongst G gene sequences, some strains sharing as little as 56.3% and 34.2% homology at the nucleotide and amino acid levels, respectively. Simultaneous co-circulation of strains belonging to the HMPV sub-genotypes B1, B2 and lineage A2b, amongst patients recruited at 2 geographically distinct provincial hospitals, was detected. Sub-genotype B2 strains were responsible for the majority of the infections detected, and a significant (p  =  0.013) association between infection with lineage A2b strains and disease severity was observed.

Prevalence and clinical and molecular characterization of human metapneumovirus in children with acute respiratory infection in China

BACKGROUND

Human metapneumovirus (HMPV), a newly discovered paramyxovirus, has been associated with acute respiratory tract infections (ARTIs). However, the prevalence and molecular characteristics of HMPV in China are still unclear.

METHODS

A total of 661 nasopharyngeal aspirates (NPA) specimens were collected from 661 children with ARTIs between December 2006 and November 2008. Specimens were screened for HMPV by reverse transcription-polymerase reaction. All positive amplification products were confirmed by sequencing.

RESULTS

HMPV was detected in 45 patients (6.80%) of the 661 children. The HMPV-infected patients were from 29 days to 9 years of age. A high incidence of HMPV infection (84.4%) was observed during the winter-spring season. Of the 45 HMPV-positive patients, 25 (55.6%) were co-infected with other respiratory viruses, and respiratory syncytial virus (RSV) was the most common additional respiratory virus. The most common clinical diagnosis was bronchopneumonia (57.8%) and cough (88.9%) was the most common clinical symptom. Phylogenetic analysis of the F gene revealed that 80% of the HMPV detected were A2, 2.2% were A1, and 17.8% were B1. Statistical analyses showed that sex, ages, seasons, and severity of the disease did not correlate with HMPV genotype (P = 0.986, 0.347, 0.660, 0.252), but viral coinfection with HMPV increased hospitalization rates (P = 0.005).

CONCLUSIONS

HMPV was frequently detected in the pediatric patients with ARTI in China. RSV was the most common coinfection virus and coinfection increased hospitalization rates. All HMPV subgroups except B2 cocirculated and there was no association found between HMPV genotypes and severity of disease.