Circulation of human metapneumovirus among children with influenza‐like illness in Wuhan,China

Human metapneumovirus (HMPV) is a worldwide distributed pathogen of the respiratory tract. The objectives of this study were to identify HMPV infections among children with influenza‐like illness (ILI) in Wuhan and to assess circulation patterns and molecular diversity of HMPV in this area. From July 2008 to December 2013, a total of 3,883 throat swab samples were collected from ILI outpatients under 16 years old. HMPV RNA was detected in 171 samples (4.40%). All the four subtypes of HMPV were identified, among which A2 was the most common subtype (61/145, 42.1%), followed by B1, B2, and A1. During the study period, HMPV circulation presented a biennial alternation between high and low incidence in Wuhan and the seasonal peak also shift between winter and spring in two continuous seasons. Subtype A2, B1, and B2 co‐circulated during the study period, with genotype A prevailing in epidemic season 2008–2009 and 2012–2013, and genotype B prevailing during other periods. This large‐scale analysis of HMPV prevalence in ILI outpatient children improves the understanding of local HMPV circulation patterns and provides molecular epidemic evidence for comparative analysis of HMPV infection. J. Med. Virol. 88:774–781, 2016. © 2015 Wiley Periodicals, Inc.

     

Spectrum of respiratory viruses circulating in eastern India: Prospective surveillance among patients with influenza‐like illness during 2010–2011

In developing countries, viruses causing respiratory disease are a major concern of public health. During January 2010–December 2011, 2,737 patients with acute respiratory infection from the outpatient departments as well as patients admitted to hospitals were screened for different respiratory viruses. Nasal and or throat swabs were collected and transported to the laboratory where initial screening of influenza A and influenza B viruses was performed. The samples were tested further for influenza C virus, parainfluenza viruses 1–4, human rhinovirus, metapneumovirus and respiratory syncytial virus by conventional RT‐ PCR. The study revealed that the majority of the patients were under 5 years of age; both due to their higher susceptibility to respiratory infections and presentation to hospitals. Out of 2,737 patients enrolled in this study, 59% were found positive for one or more respiratory viruses. Influenza B infection was detected in 12% of patients followed by influenza A (11.7%), respiratory syncytial virus (7.1%), parainfluenza virus‐2 (6%), metapneumovirus (3%), parainfluenza virus‐3 (1%), parainfluenza virus‐4 (0.6%), parainfluenza virus‐1 (0.3%), influenza C (0.2%) and human rhinovirus (0.2%). Distinct seasonal infection was observed only for influenza A and influenza B viruses. J. Med. Virol. 85:1459–1465, 2013 . © 2013 Wiley Periodicals, Inc.

     

Surveillance of 16 respiratory viruses in patients with influenza‐like illness in Nanjing,China

Much less is known about the etiology of influenza‐like illness in China. A continuous surveillance of 16 respiratory viruses was conducted from November 2010 to October 2011 of outpatients with influenza‐like illness in Nanjing, China. The two largest general hospitals and a provincial virus laboratory in Nanjing participated in this study. Throat swabs were collected from outpatients during medical visits for influenza‐like illness and were tested for 16 respiratory viruses using PCR. Three hundred seventeen viruses were detected in samples from 246 (50.6%) patients with influenza‐like illness. The viruses found mostly commonly were influenza, rhinovirus, hCoV HKU1, and adenovirus. The identification rates of respiratory viruses differed significantly among different sampling seasons (P = 0.0002). The rates of influenza A and hCoV HKU1 were much higher during the influenza‐like illness winter peak than during the influenza‐like illness summer peak and other months. Co‐infections were detected in 57 (11.7%) patients and were found most commonly in adults older than 60 years. RSV was detected in 5.9% and 2.6% of patients who were 0–5 and 6–15 years old, respectively, but was not detected in other age groups. This study confirmed that multiple respiratory viruses may circulate concurrently in the population and account for a large proportion of influenza‐like illness. In addition to influenza virus, hCoV HKU1 may be associated with the influenza‐like illness winter peak in Nanjing, China. J. Med. Virol. 84:1980–1984, 2012. © 2012 Wiley Periodicals, Inc.     

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

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

     

Immunogenicity of recombinant human bocavirus‐1,2 VP2 gene virus‐like particles in mice

Human bocavirus (HBoV), a recently identified pathogen with a worldwide distribution is closely related to paediatric acute respiratory infection and gastroenteritis. The present study was performed to evaluate the immunogenicity of HBoV1 and HBoV2 virus‐like particles (VLPs) as vaccine candidates in mice. Both HBoV1 and HBoV2 VLPs were expressed in the bacmid virus–SF9 cell system. Mice were inoculated three times at 3‐week intervals with HBoV VLPs at one dose intramuscular (i.m.) or intradermal (i.d.) with or without the addition of the alum adjuvant. ELISA was used to detected antibody, and ELISPOT was used to test cellular immune responses. HBoV‐specific IgG antibodies were induced and alum adjuvant improved the antibody titres and avidity, while the inoculation pathway had no influence. T helper type 1/ type 2 immune responses were balanced induced by HBoV1 VLPs but not HBoV2 VLPs. Serum IgG antibody cross‐reactivity rates of the two subtypes were similar, but cross‐reactions of HBoV1 immunization groups were higher. The single i.m. group had more interferon‐γ‐secreting splenocytes. These data indicate that HBoV VP2 VLPs have good immunogenicity with induction of strong humoral and cellular immune responses, and they may be potential candidate vaccines for HBoV infection.     

Epidemiological and clinical study of viral respiratory tract infections in children from Italy

Impact of recently discovered viruses on epidemiology of acute respiratory tract infections (ARTI) is still unclear. We studied the impact of recently discovered human metapneumovirus (hMPV), human bocavirus (HBoV), and new coronaviruses (HCoV‐NL63 and HKU1) on the global epidemiology of ARTI. From October 2006 to April 2007, 237 pediatric patients affected by ARTI were enrolled in our study. Specimens were tested for respiratory viruses by polymerase chain reaction. One hundred twenty‐four out of 237 samples (52.3%) were positive for one or more viruses. Picornaviruses were the most prevalent viruses (n = 61, 43.6%), followed by respiratory syncytial virus (n = 34, 24.3%) and Adenovirus (n = 25, 17.9%); hMPV (n = 9, 6.4%) was the fourth most common virus detected. HBoV and HCoV showed a low prevalence (respectively 2.9% and 2.1%). RSV was the prevalent agent of LRTI (38%). Viruses were identified in more than 50% of the studied ARTI, providing useful information on clinical features and epidemiology of specific agents affecting children in cold months. Although routine surveillance of respiratory viruses does not seem cost‐effective, continuous monitoring of ARTI etiology could be a useful tool for planning resources for the development of new vaccines and antiviral agents. J. Med. Virol. 81:750–756, 2009 © 2009 Wiley‐Liss, Inc.     

Viruses in community-acquired pneumonia in children aged less than 3 years old: High rate of viral coinfection

The occurrence of viral coinfections in childhood pneumonia has received little attention, probably because suitable detection methods have been lacking. Between November 2004 and October 2006, the presence of 14 respiratory viruses in children aged less than 3 years old with community-acquired pneumonia were investigated using molecular or immunochromatographic techniques and/or viral culture. A total of 315 children (338 episodes) were included, and hospitalization was required in 178 episodes. At least one virus was detected in 66.9% of the episodes and simultaneous detection of two or more viruses was frequent (27% of the episodes with viral detection). The most frequently detected virus was respiratory syncytial virus (n = 67: 33 subgroup A, 33 subgroup B, 1 not typed), followed by human bocavirus (n = 48), rhinovirus (n = 46), human metapneumovirus (n = 39: 13 genotype A2, 8 B1, 5 B2, 1 A1, 12 not genotyped) and parainfluenza viruses (n = 38: 1 type 1, 3 type 2, 22 type 3, 11 type 4 and 1 not typed). The 14 viruses investigated were found in viral coinfections, which were more frequent in children aged less than 12 months. Except for adenovirus, the incidence of which was low, the percentage of viral coinfection ranged between 28.2% and 68.8%. Children with viral coinfection more frequently required hospital admission than those with single viral infection. It is concluded that viral coinfections are frequent in children aged less than 3 years old with community-acquired pneumonia and can be a poor prognostic factor.     

Pteropine orthoreovirus infection among out‐patients with acute upper respiratory tract infection in Malaysia

This study aims to assess the incidence rate of Pteropine orthreovirus (PRV) infection in patients with acute upper respiratory tract infection (URTI) in a suburban setting in Malaysia, where bats are known to be present in the neighborhood. Using molecular detection of PRVs directly from oropharyngeal swabs, our study demonstrates that PRV is among one of the common causative agents of acute URTI with cough and sore throat as the commonest presenting clinical features. Phylogenetic analysis on partial major outer and inner capsid proteins shows that these PRV strains are closely related to Melaka and Kampar viruses previously isolated in Malaysia. Further study is required to determine the public health significance of PRV infection in Southeast Asia, especially in cases where co‐infection with other pathogens may potentially lead to different clinical outcomes. J. Med. Virol. 87:2149–2153, 2015. © 2015 Wiley Periodicals, Inc.

     

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.     

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

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

Prevalence of WU and KI polyomaviruses in plasma, urine, and respiratory samples from renal transplant patients

WU and KI polyomaviruses (WUPyV, KIPyV) have been detected in respiratory, blood, stool, and lymphoid tissue, but not in urine samples. PCR based detection revealed higher frequency in immunocompromised individuals. In this study the prevalence of WUPyV and KIPyV was analyzed in respiratory, urine, and blood samples from renal transplant patients compared with healthy individuals. WUPyV and KIPyV were detected by nested PCR. The PCR products were sequenced and viral DNA loads were determined by quantitative real-time PCR. WUPyV and KIPyV were found in plasma (3.6%; 7/195), urine (14%; 7/50), and respiratory samples (10%; 9/90) of renal transplant patients, but not in plasma (0/200) and urine (0/36) specimens from healthy blood donors. WUPyV and KIPyV were detected mainly early after renal transplantation and the viral loads were low. A higher prevalence of WUPyV was found in plasma and urine samples, KIPyV was found more frequently in respiratory samples from renal transplant patients. It is hypothesized that immunosuppression due to the transplantation may result in reactivation of these viruses or may establish greater susceptibility to infection with KIPyV and WUPyV.     

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

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

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

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