Detection Of Human Metapneumovirus Research Articles

Pathogenic agents causing acute respiratory tract infections in pediatric patients in Spring, 2023, in Beijing

Objective: To explore the pathogenic agents of acute respiratory infection (ARI) in children in Beijing. Methods: In the cross-sectional study, 3 groups of children from different departments were enrolled from Feb 6th, 2023 (6th week) to May 28th (21th week), 2023, including influenza-like case group from emergency department for nucleic acid testing of influenza virus (Flu) and human metapneumovirus (HMPV), the outpatient ARI group under nucleic acid testing for Flu, respiratory syncytial virus (RSV), adenovirus (ADV), and parainfluenza virus (PIV), and the inpatient ARI group under nucleic acid testing for Flu, RSV, HMPV, ADV, human bocavirus (HBoV), Rhinovirus (Rh), PIV, coronavirus (HCoV), Mycoplasma pneumoniae (Mp) and Chlamydia pneumonia (Cp). Results: There were 320 influenza-like cases enrolled, including 192 males and 128 females, aged 4.7 (3.6, 6.9) years, and 117 cases (36.6%) positive for Flu A, which contained similar proportion of pandemic H1N1 (H1N1) 47.0% (55/117) and H3N2 53.0% (62/117), and 13 cases for HMPV 4.1% (13/320). The rate of Flu reached its peak at the 10th week, with H1N1 as the predominant one from the 6th to 9th week (10.0%-50.0%) and then H3N2 from the 10th to 16th week (15.0%-90.0%). HMPV was detected from the 15th week 5.0% (1/20), and then reached to 30.0% (6/20) at the 20th week. In the outpatient ARI group, 7 573 were enrolled, including 4 131 males and 3 442 females, aged 4.0 (2.1, 5.3) years, and the highest positive rate for RSV 32.9% (2 491/7 573), followed by Flu A 12.1% (915/7 573). The dominant one was Flu A in weeks 6-14 (23.2%-74.7%), then RSV in the 15th week 24.8% (36/145). In the inpatient ARI group, 1 391 patients were enrolled, including 804 males and 587 females, aged 3.3 (0.4, 5.8) years, and the highest positive rate for Rh 18.7% (260/1 391), followed by RSV 12.4% (173/1 391), Flu A 10.2% (142/1 391, of which 116 cases (81.7%) were H1N1, and 26 cases (18.3%) were H3N2) and HMPV 3.1% (43/1 391). H1N1 was detected from the 7th week 10% (6/60), to peak in the 11th week 31.8% (21/66). H3N2 was detected from the 8th week 1.5% (1/68), and then kept in low level. The proportion of H1N1 among Flu was 81.7% (116/142) in the inpatient ARI group. RSV was detected from 12th week 1.3% (1/80), reaching 30.4% (35/115) at 19th week. The positive rate of HMPV reached 12.1% (14/116) at 21th week. Conclusions: In the spring of 2023, the first one in Beijing is the Flu epidemic, with H1N1 being the predominant one in the early stage and H3N2 in the later stage. Then, there is a postponed RSV epidemic and an increased HMPV detection. In addition, nucleic acid testing for outpatient children should be strengthened to provide early warning of epidemics.

Clinical significance of human metapneumovirus detection in critically ill adults with lower respiratory tract infections

BackgroundUnlike other viruses, the pathogenicity of human metapneumovirus (hMPV) in adults remains uncertain. To address this question, a retrospective monocentric cohort including all patients admitted to ICU with hMPV infection between January 1, 2010, and June 30, 2018 was performed. The characteristics of hMPV infected patients were studied and compared to matched influenza infected patients. Consecutively, a systematic review and meta-analyses investigating PUBMED, EMBASE and COCHRANE databases was conducted to explore the hMPV infections in adult patients (PROSPERO number: CRD42018106617). Trials, case series, and cohorts published between January 1, 2008 and August 31, 2019 compiling adults presenting hMPV infections were included. Pediatric studies were excluded. Data were extracted from published reports. Primary endpoint was the rate of low respiratory tract infections (LRTIs) among all hMPV infected patients.ResultsDuring the study period, 402 patients were tested positive for hMPV. Among them 26 (6.5%) patients were admitted to the ICU, 19 (4.7%) for acute respiratory failure. Twenty-four (92%) were immunocompromised. Bacterial coinfections were frequent 53.8%. Hospital mortality rate was 30.8%. In the case–control analysis, the clinical and imaging characteristics were not different between hMPV and influenza infected patients. The systematic review identified 156 studies and 69 of them (1849 patients) were eligible for analysis. Although there was heterogeneity between the studies, the rate of hMPV LRTIs was 45% (95% CI 31–60%; I2 = 98%). Intensive care unit (ICU) admission was required for 33% (95% CI 21–45%; I2 = 99%). Hospital mortality rate was 10% (95% CI 7–13%; I2 = 83%) and ICU mortality rate was 23% (95% CI 12–34%; I2 = 65%). Underlying malignancy was independently associated with increased mortality rate.ConclusionsThis preliminary work suggested that hMPV may be associated with severe infection and high mortality in patients with underlying malignancies. However, regarding the small size of the cohort and the heterogeneity of the review, more cohort studies are warranted.

Recent Changes in the Human Metapneumovirus Outbreak at a University Hospital in Korea.

Although the detection of respiratory viruses other than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was significantly reduced because of quarantine due to the coronavirus disease (COVID-19) pandemic, an epidemic of several viruses was reported unexpectedly. We also detected a change in the pattern of human metapneumovirus (HMPV) outbreak compared to that before the COVID-19 pandemic. Therefore, the authors intended to identify the incidence and altered distribution pattern of the HMPV outbreak and provide useful information for clinical practice. This retrospective study investigated the incidence and distribution of HMPV from March 2020 to December 2022 during the COVID-19 pandemic. Detection of respiratory microorganisms was performed by multiplex polymerase chain reaction using a commercial kit and FilmArray assay. The overall incidence of at least one respiratory microorganism was 50.3% (1,152/2,290). HMPV was not detected between March 2020 and June 2022. However, it was suddenly detected in July 2022 and continued for approximately five months until November 2022. In particular, the detection rate of HMPV was high in September and October 2022, accounting for approximately 76.1% (51/67) of the total HMPV-positive cases. Seasonally, 92.5% (62/67) of HMPV cases were detected in autumn, while the rest of the cases were detected in summer. The HMPV detection rate, according to the age group, was highest in group 4 (3 - 6 years) at 7.4% (27/367), followed by group 3 (4 months to 2 years) at 3.6% (31/861). In HMPV-positive cases, the rate of more than two respiratory pathogens was 46.3% (31/67). An analysis of co-infecting pathogens showed that HMPV with rhinovirus A/B/C/ enteroviruses accounted for the highest percentage (51.6%), followed by HMPV with respiratory syncytial virus (48.4%). The COVID-19 pandemic has caused several changes in our lives. This study confirmed that the seasonal distribution of HMPV was different from that before the COVID-19 pandemic. Therefore, it can be assumed that the distribution of other respiratory microorganisms could have changed and it appears that changes could occur in previously known viral epidemiology. Clinicians should therefore be alert to this possibility.

Detection of human Metapneumovirus and respiratory Syncytial Virus associated with asthmatic patients using direct fluorescent assay and Real time – PCR

This study aimed to determine the incidence of human respiratory syncytial virus (hRSV) and metapneumovirus (hMPV) occurrence in asthmatic patients in Wasit province. Blood samples were collected for measure the total and differential white blood cells count (WBCs). Correlation results of total and differential WBCs count for neutrophils, lymphocytes, eosinophils and basophils count among studied groups were significant (P <0.001). Enzyme linked immunosorbent assay (ELISA) technique has been applied for detection of total-IgE antibodies. Results revealed that the highest total-IgE antibodies titer in sera were significantly difference (p < 0.01). A total of 80 nasopharyngeal swabs were immediately dipped in transport media and stored until using for the detection of suspected hRSV and hMPV patients group by direct fluorescent assay the results appeared 13 (16.25 %) and 11 (13.75 %) samples were given positive results for hRSV and hMPV, respectively. Results of hRSV in asthmatic patients were subjected to real time – polymerase chain reaction (RT-PCR) appeared 15 samples out of 80 samples (18.75 %) were gave positive result for this test.

Correlation between Children Respiratory Virus Infections and Climate Factors

AbstractObjective Respiratory viruses are the most important cause of lower respiratory tract infections (LRTI) in children. Meteorological factors can influence viral outbreaks. The objective of this study was to determine the association between climate variables and respiratory virus detection.Methods Multicenter prospective 1-year surveillance was conducted among children hospitalized for LRTI in Tunisia. Nasopharyngeal aspirates were tested by direct immunofluorescence assay (DIFA) for the detection of respiratory syncytial virus (RSV); adenovirus (AdV); influenza virus (IFV) A and B; and parainfluenza virus 1, 2, and 3 (PIV1/2/3). Samples were further analyzed by reverse-transcription polymerase chain reaction for the detection of human metapneumovirus (hMPV). Monthly meteorological data were determined by consulting the National Institute of Meteorology and the World Weather Online Meteorological Company websites. Pearson's correlation tests were used to determine the statistical association between the detection of respiratory viruses and climatic characteristics.Results Among 572 patients, 243 (42.5%) were positive for at least one virus. The most frequently detected viruses by DIFA were RSV (30.0%), followed by IFVA (3.8%), IFVB (3.5%), PIV (0.9%), and AdV (0.9%). HMPV was detected in 13 RSV-negative samples (3.3%). Dual infections were detected in seven cases (1.2%). Monthly global respiratory viruses and RSV detections correlated significantly with temperature, rainfall, cloud cover, wind speed, wind temperature, and duration of sunshine. Monthly IFV detection significantly correlated with rainfall, wind speed, wind temperature, and duration of sunshine. HMPV detection significantly correlated with temperature and wind temperature.Conclusion Respiratory viral outbreaks are clearly related to meteorological factors in Tunisia.

Advances in laboratory assays for detecting human metapneumovirus.

Human metapneumovirus (HMPV) is one of the major causes of acute respiratory tract infection (ARI) and shows high morbidity and mortality, particularly in children and immunocompromised patients. Various methods for detecting HMPV have been developed and applied in clinical laboratories. When reviewing the literature, we found that polymerase chain reaction (PCR)-based assays have been most frequently and consistently used to detect HMPV. The most commonly used method was multiplex reverse transcriptase-PCR (RT-PCR; 57.4%), followed by real-time RT-PCR (38.3%). Multiplex RT-PCR became the more popular method in 2011–2019 (69.7%), in contrast to 2001–2009 (28.6%). The advent of multiplex PCR in detecting broader viral pathogens in one run and coinfected viruses influenced the change in user preference. Further, newly developed microarray technologies and ionization mass spectrometry were introduced in 2011–2019. Viral culture (including shell vial assays) and fluorescent immunoassays (with or without culture) were once the mainstays. However, the percentage of studies employing culture and fluorescent immunoassays decreased from 21.4% in 2001–2010 to 15.2% in 2011–2019. Meanwhile, the use of PCR-based methods of HMPV detection increased from 78.6% in 2001–2010 to 84.8% in 2011–2019. The increase in PCR-based methods might have occurred because PCR methods demonstrated better diagnostic performance, shorter hands-on and run times, less hazards to laboratory personnel, and more reliable results than traditional methods. When using these assays, it is important to acquire a comprehensive understanding of the principles, advantages, disadvantages, and precautions for data interpretation. In the future, the combination of nanotechnology and advanced genetic platforms such as next-generation sequencing will benefit patients with HMPV infection by facilitating efficient therapeutic intervention. Analytical and clinical validation are required before using new techniques in clinical laboratories.

Baseline characteristics and clinical symptoms related to respiratory viruses identified among patients presenting with influenza-like illness in primary care

ObjectivesWe aimed to identify patients' clinical characteristics associated with respiratory viruses identified among patients presenting with influenza-like illness (ILI). MethodsA sample of patients of all ages presenting with ILI was included by physicians of the French Sentinelles network during two seasons (2015/16 and 2016/17). Nasopharyngeal samples were tested for the presence of influenza virus (IV), respiratory syncytial virus (RSV), human rhinovirus (HRV) and human metapneumovirus (HMPV). Patients' characteristics associated with each of the four virus classes were studied using multivariate logistic regressions. ResultsA total of 5859 individuals were included in the study: 48.0% tested positive for IV, 7.9% for HRV, 7.5% for RSV and 4.1% for HMPV. Cough was associated with IV (OR 2.14, 95% CI 1.81–2.52) RSV (OR 2.52, 95% CI 1.75–3.74) and HMPV detection (OR 2.15, 95% CI 1.40–3.45). Rhinorrhoea was associated mainly with HRV detection (OR 1.75, 95% CI 1.34–2.32). Headache was associated with IV detection (OR 1.75, 95% CI 1.34–2.32), whereas absence of headache was associated with RSV and HMPV detection. Dyspnoea was associated with RSV detection (OR 2.33, 95% CI 1.73–3.12) and absence of dyspnoea with IV detection. Conjunctivitis was associated with IV detection (OR 1.27, 95% CI 1.08–1.50). Some associations were observed only in children: dyspnoea and cough with RSV detection (age <5 years), conjunctivitis with IV detection (age <15 years). Period of onset of symptoms differed among aetiological diagnoses. Seasonal influenza vaccination decreased the risk of IV detection (OR, 0.67, 95% CI 0.51–0.86). ConclusionsThis study allowed the identification of symptoms associated with several viral aetiologies in patients with ILI. A proper knowledge and understanding of these clinical signs may improve the medical management of patients.

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

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

Clinical evaluation of the isothermal amplification assays for the detection of four common respiratory viruses in children with pneumonia.

Respiratory viruses are recognized as serious causes of morbidity and mortality in lower respiratory tract infections in patients. Isothermal amplification assays are increasingly used in their detection because of their rapidity, simplicity and cost-effectiveness, when compared to traditional molecular diagnostic methods. However, systematic assessment of these assays in the clinical settings is rarely reported. MEDLINE (Pubmed) searches were done analysing subject headings and words in the abstract related to isothermal amplification assay and virus. Selected loop-mediated isothermal amplification assays (LAMP) for respiratory syncytial virus (RSV), human metapneumovirus (HMPV) and adenovirus (ADV) as well as a reverse transcription genome exponential amplification reaction assay (GEAR) for human rhinovirus (HRV) were clinically evaluated in a head to head comparison against a two-tube multiplex reverse transcription-PCR (RT-PCR) assay (two-tube assay) using 634 respiratory specimens from children with pneumonia from different regions in China. Discrepant results between isothermal amplification assays and the two-tube assay were resolved by sequencing. A comparison of sensitivities of each selected isothermal amplification assay among province, gender, and age groups was also analyzed. A total of 634 respiratory specimens selected from Hebei Province children's hospital and Hunan Provincial Center for Disease Control and Prevention were tested. The overall detection rate (number of positive specimens/total specimens) for viruses tested by Reverse transcription (RT)-LAMP/LAMP/RT-GEAR was 35.9% while the detection rate was 46.2% by the two-tube assay. The sensitivity of each isothermal amplification assay was 88.4%, 74.3%, 100% and 73.6% for RSV, HMPV, ADV and HRV, respectively. No false positives were found in isothermal amplification assays. All the discrepant negative results by isothermal amplification assays were confirmed false negatives by sequencing. The LAMP assay for ADV showed significant consistency with the two-tube assay. A higher sensitivity of RSV detection was found in Hunan Province than in Hebei Province (P=0.01). Among different age groups, a higher sensitivity of RSV detection was also found in children older than 1year, when compared to children less than 1year (P=0.01). The clinical performance of the selected isothermal amplification assays for different viruses varies. Multiple-center assessment is critical to evaluate isothermal amplification assays, especially for RNA viruses, for their broad use in clinical hospital. The selected LAMP assay for the detection of ADV is reliable and has great potential for use in clinics; however, the sensitivities of the LAMP/GEAR assays for the detection of RSV, HMPV and HRV need to be further improved to meet clinical requirements, although a statistical difference in sensitivity was only found for the selected LAMP assay for RSV.

Detection of Human Metapneumovirus and Respiratory Syncytial Virus by Real-Time Polymerase Chain Reaction Among Hospitalized Young Children in Iran.

BackgroundAcute respiratory infection plays an important role in hospitalization of children in developing countries; detection of viral causes in such infections is very important. The respiratory syncytial virus (RSV) is the most common etiological agent of viral lower respiratory tract infection in children, and human metapneumovirus (hMPV) is associated with both upper and lower respiratory tract infections among infants and children.ObjectivesThis study evaluated the frequency and seasonal prevalence of hMPV and RSV in hospitalized children under the age of five, who were admitted to Aliasghar children’s hospital of Iran University of Medical Sciences from March 2010 until March 2013.Patients and MethodsNasopharyngeal or throat swabs from 158 hospitalized children with fever and respiratory distress were evaluated for RSV and hMPV RNA by the real-time polymerase chain reaction (PCR) method.ResultsAmong the 158 children evaluated in this study, 49 individuals (31.1%) had RSV infection while nine individuals (5.7%) had hMPV infection. Five (55.5%) of the hMPV-infected children were male while four (44.5%) were female and 27 (55.2%) of the RSV-infected patients were females and 22 (44.8%) were males. The RSV infections were detected in mainly < one year old children and hMPV infections were detected mainly in > one year old children. Both RSV and hMPV infections had occurred mainly during winter and spring seasons.ConclusionsRespiratory syncytial virus was the major cause of acute respiratory infection in children under one-year of age while human metapneumovirus had a low prevalence in this group. The seasonal occurrence of both viruses was the same.

Detecção de metapneumovírus humano em crianças portadoras de infecções respiratórias agudas atendidas em um hospital de urgência e emergência em Belém, Estado do Pará, Brasil

OBJETIVO: Realizar avaliacao clinica e deteccao de metapneumovirus humano (MPVh) de criancas abaixo de 5 anos de idade, portadoras de infeccoes respiratorias agudas (IRA), com livre procura ou referenciadas a um hospital de urgencia e emergencia em Belem, Estado do Para, Brasil. MATERIAIS E METODOS: Estudo longitudinal prospectivo (marco de 2008 a fevereiro de 2009), avaliando 67 amostras de secrecoes nasofaringeas de 67 pacientes com IRA - 29,9% com doenca limitada ao sistema respiratorio superior (DSRS) e 70,1% com doenca do sistema respiratorio inferior (DSRI) e DSRS - por meio de reacao em cadeia mediada pela polimerase precedida de transcricao reversa em tempo real. RESULTADOS: Na coorte de n = 67 criancas investigadas, foram detectados 13 casos (19,4%) positivos para MPVh. Houve maior porcentagem de identificacao viral (61,5%) naqueles com DSRS associadas a DSRI, em relacao aos com DSRS (38,5%). CONCLUSAO: Foi observado que o MPVh e um agente etiologico prevalente em 19,4% das criancas com IRA, no entanto, as manifestacoes clinicas avaliadas nao ocorrem exclusivamente em associacao com o MPVh.

Targeted Proteomics of Human Metapneumovirus in Clinical Samples and Viral Cultures.

The rapid, sensitive, and specific identification of infectious pathogens from clinical isolates is a critical need in the hospital setting. Mass spectrometry (MS) has been widely adopted for identification of bacterial pathogens, although polymerase chain reaction remains the mainstay for the identification of viral pathogens. Here, we explored the capability of MS for the detection of human metapneumovirus (HMPV), a common cause of respiratory tract infections in children. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) sequencing of a single HMPV reference strain (CAN97-83) was used to develop a multiple reaction monitoring (MRM) assay that employed stable isotope-labeled peptide internal standards for quantitation of HMPV. Using this assay, we confirmed the presence of HMPV in viral cultures from 10 infected patients and further assigned genetic lineage based on the presence/absence of variant peptides belonging to the viral matrix and nucleoproteins. Similar results were achieved for primary clinical samples (nasopharyngeal aspirates) from the same individuals. As validation, virus lineages, and variant coding sequences, were confirmed by next-generation sequencing of viral RNA obtained from the culture samples. Finally, separate dilution series of HMPV A and B lineages were used to further refine and assess the robustness of the assay and to determine limits of detection in nasopharyngeal aspirates. Our results demonstrate the applicability of MRM for identification of HMPV, and assignment of genetic lineage, from both viral cultures and clinical samples. More generally, this approach should prove tractable as an alternative to nucleic-acid based sequencing for the multiplexed identification of respiratory virus infections.

Human metapneumovirus-associated severe acute respiratory illness hospitalisation in HIV-infected and HIV-uninfected South African children and adults

BackgroundData on human metapneumovirus (HMPV)-associated severe acute respiratory illness (SARI) are limited in settings with high human immunodeficiency virus (HIV) infection prevalence. ObjectivesTo describe clinical characteristics and seasonality (all sites), and incidence (Soweto only) of HMPV-associated SARI among children and adults. Study designActive, prospective, hospital-based, sentinel surveillance for patients hospitalised with SARI was conducted at four sites in South Africa from February 2009–December 2013. Upper respiratory tract samples were tested by multiplex real-time polymerase chain reaction assays for HMPV and other respiratory viruses. Incidence of hospitalisation, stratified by age and HIV-infection status, was calculated for one hospital with population denominators. ResultsHMPV was identified in 4.1% of patients enrolled, including 5.6% (593/10503) in children and 1.7% in adults (≥18 years; 119/6934). The majority of adults (84.0%) had an underlying medical condition, including HIV infection in 87/110 (79.1%). HMPV detection occurred perennially with periods of increased detection, which varied from year to year. The incidence of HMPV-associated hospitalisation in Soweto was highest in infants (653.3 per 100,000 person years; 95% confidence interval (CI) 602.2–707.6). The incidence was higher in HIV-infected persons compared to HIV-uninfected persons in age-groups 5–17 years (RR 6.0; 1.1–20.4), 18−44 years (RR 67.6; 38.0–132.6) and 45–64 years (RR 5.3; 3.4–8.3), while not differing in other age-groups. ConclusionsThe burden of HMPV-associated SARI hospitalisation among adults occurred predominantly in HIV-infected persons. Among children, infants were at highest risk, with similar burden of hospitalisation in HIV-infected and HIV-uninfected children.

Detection of Human Metapneumovirus in Hospitalized Children with Acute Respiratory Tract Infections in Sulaimani Province, Iraq

Background: Human Metapneumovirus (hMPV) is a member of Paramyxoviridae family. It is an important viral pathogen of respiratory tract infections among children. Therefore, the aim of this study is to determine the incidence of hMPV infections among children less than 5 years of age with respiratory tract infections at the pediatric hospital in Sulaimani city of Iraq. Also, this study aims to evaluate the different diagnostic methods for the detection of this virus. Method: Nasopharyngeal swabs and throat swabs were collected from 300 hospitalized children with respiratory infections under 5 years of age between April 2011 and March 2012. Each sample was used for hMPV detection by conventional reverse transcriptase (RT-PCR) and direct fluorescent assay (DFA). A questionnaire which was designed for acute respiratory tract infections among hospitalized children was also included. Results: Human Metapneumovirus was detected in 16% by RT-PCR and 14.7% by DFA. Autumn – winter period was the most common season for hMPV infections with its peak occurrence in January and February. Conclusions: hMPV is an important pathogen associated with RTIs in children. RT-PCR is highly sensitive and specific for the detection of hMPV than antigen detection methods used for the diagnosis of hMPV viruses.

Detection of Human Metapneumo Virus among Infants with Bronchiolitis

Detection of Human Metapneumo Virus among Infants with Bronchiolitis

Development of real-time RT-PCR for detection of human metapneumovirus and genetic analysis of circulating strains (2009-2011) in Pune, India

Human metapneumovirus (HMPV) is an important respiratory virus implicated in respiratory infections. The purpose of this study was to develop a one-step real-time RT-PCR assay that can detect all four lineages of HMPV and to identify the HMPV lineages circulating in Pune, India. Conserved regions of the nucleoprotein gene were used to design real-time primers and a probe. A total of 224 clinical samples that were positive for different respiratory viruses (including 51 samples that were positive for HMPV) were tested using the real time RT-PCR assay, and the specificity of the assay was observed to be 100 %. Using in vitro-synthesized RNA, the sensitivity of the assay was ascertained to be 100 copies of the target gene per reaction. Phylogenetic analysis of the nucleoprotein (N) and attachment glycoprotein (G) genes confirmed that this assay detected all lineages of HMPV. A2, B1 and B2 strains were observed during the study period. Our assay is highly sensitive and specific for all known lineages of HMPV, making it a valuable tool for rapid detection of the virus. A2 and B2 were the predominant subtypes circulating in Pune, Western India.

Molecular Detection of Human Metapneumovirus and Human Bocavirus on Oropharyngeal Swabs Collected from Young Children with Acute Respiratory Tract Infections from Rural and Peri-Urban Communities in South India

BackgroundAcute respiratory tract infections (ARTIs) are one of the major causes of morbidity and mortality among young children in developing countries. Information on the incidence of human metapneumovirus (hMPV) and human bocavirus (HBoV) infections in developing countries, especially among rural children, is very limited.ObjectivesThis study was conducted to identify whether these viruses were associated with ARTI among children ≤5 years of age in rural and peri-urban populations in South India.MethodsThe study was cross-sectional with prospective sample collection. Oropharyngeal swabs were collected from children ≤5 years of age presenting with ARTI. None of the children in this study were known to have any immunosuppressive conditions. The two viruses, hMPV and HBoV, were identified using semi-nested polymerase chain reaction (PCR) assays and one-step PCR assays, respectively. The lower limits of detection of hMPV and HBoV were 6.69 × 105 plasmid copies and 5.77 × 103 plasmid copies, respectively, per 5 μL PCR reaction input.ResultsThe frequency of hMPV infection in children was higher than that of HBoV infection. The different frequencies of hMPV in patients in various age groups with upper and lower respiratory tract infections were compared, and the variance was found to be insignificant. In the 38 children who were hMPV positive, the majority (73.7 %) were from rural communities. The overall hMPV-positive rate was higher in the rural population than in the peri-urban population, but the difference was statistically insignificant. The youngest age at which hMPV-positive status was recorded was 5 months.ConclusionThis study demonstrated that hMPV was associated with a significant number (i.e. >10 %) of ARTIs in children in South India, whereas a relatively smaller number of HBoV infections was observed.

Rapid Detection of Human Metapneumovirus in Children with Acute Respiratory Tract Infection

Rapid Detection of Human Metapneumovirus in Children with Acute Respiratory Tract Infection

Real-time reverse transcriptase PCR assay for improved detection of human metapneumovirus

BackgroundHuman metapneumovirus (HMPV) is a paramyxovirus with multiple genetic lineages that is a leading cause of acute respiratory disease. Several RT-PCR assays have been described based on limited available sequence data. ObjectivesTo develop a broadly reactive real-time RT-PCR assay for HMPV that allows for a rapid, sensitive, and specific detection in a clinical or research setting. Study designThree published assays for HMPV were modified based on analysis of multiple HMPV sequences obtained from GenBank. Original and modified assays were tested against prototype HMPV strains from each genetic sublineage, multiple isolates of HMPV from different years, a collection of clinical specimens, and commercial validation panels. ResultsA number of potential sequence mismatches with diverse HMPV strains were identified. Modifications were made to oligonucleotides to improve annealing efficiency. Primers and probes based on newer sequence data offered enhanced detection of all subgroups, especially for low titer specimens. The new primers and probe detected multiple clinical isolates of HMPV collected over a twenty-year period. The modified assay improved detection of HMPV in a panel of clinical specimens, and correctly identified HMPV samples in two commercial validation sets. ConclusionsWe report a modified real-time RT-PCR assay for HMPV that detects all genetic lineages with high sensitivity.

Human Metapneumovirus in the Cerebrospinal Fluid of a Patient With Acute Encephalitis

To report, to our knowledge, the first case of detection of human metapneumovirus in the cerebrospinal fluid of a patient during acute encephalitis. Case report. University hospital. A 10-year-old girl with acute encephalitis. Human metapneumovirus was detected in cerebrospinal fluid and nasal-wash specimens during the initial phase of mild encephalitis. Abrupt clinical deterioration was associated with the presence of multiple areas of demyelination and cortical abnormalities. Demyelinated areas improved after immunomodulatory therapy, but cortical lesions spread in both hemispheres. Surprisingly, clinical worsening occurred when the virus became undetectable in cerebrospinal fluid. The detection of human metapneumovirus in cerebrospinal fluid strongly suggests its causative role in acute encephalitis. The evolution of the clinical and radiological features provided insight into the pathogenesis of human metapneumovirus encephalitis.