WUPyV Research Articles

Respiratory virus infections among children in South China

Acute respiratory tract infection is an important cause of morbidity and mortality with a worldwide disease burden. This study aimed to determine the prevalence and clinical characteristics of children with viral-induced acute respiratory tract infection, in Southern China. Nasopharyngeal aspirate samples from 1,980 pediatric patients with suspected acute respiratory tract infection, and 82 samples from healthy subject controls were collected for routine examination at the Second Affiliated Hospital of Shantou University Medical College, from October 2007 to August 2011. Specimens were tested by multiplex polymerase chain reaction (mPCR). At least one or more viruses were detected from 1,087 samples (54.9%). These included laboratory confirmations for 446 respiratory syncytial virus (RSV), 386 influenza virus A (FluA), 315 human rhinovirus (HRV), 135 human bocavirus (HBoV), 119 Parainfluenza virus 3 (PIV3), 82 Parainfluenza virus 1 (PIV1), 66 adenovirus (ADV), 53 WU polyomavirus (WUPyV), 52 human metapneumovirus (hMPV), and 29 influenza virus B (FluB) samples. Samples from healthy subjects were negative for any virus. Of the patients with positive specimens, 107 (9.8%) were admitted to pediatric intensive care unit (PICU). Co-infection with at least two of the viral pathogens under study was observed in 325 of the 1,980 patients (16.4% of the total number of cases). These findings may help in the diagnosis of viral infections of the respiratory tract in children, and help to consider current and potential therapeutic approaches for the treatment of acute respiratory tract infection, and further respiratory complications.

Development of High-throughput Liquid Chips for Respiratory Virus Detection

Diagnosis of viral respiratory tract infections clinically is often nonspecific, and a rapid, high-throughput laboratory technique which can detect major respiratory viruses is desirable. Two liquid chip panels were developed which used a target-enriched multiplexed RT-PCR amplification followed by Luminex liquid chip hybridization based on xMAP technology. One was for the detection of 5 type/ subtypes of the influenza virus (called Influenza Panel), the other was for the identification of 14 major respiratory viruses, including emerging human metapneumovirus (HMPV), coronavirus (CoV NL63, HKU1), human bocavirus (HBoV), and WU polyomavirus (WUPyV) (called Respiratory Panel). The analytical sensitivity and specificity of these two panels were determined. 108 throat swabs from influenza-like-illness (ILI) cases and 88 nasopharyngeal aspirates (NPA) from hospitalized children with lower respiratory tract infections (LRTI) were used to evaluate the two panels. The Influenza Panel returned the analytical sensitivity of 4 - 10 copies vRNA/microL of sample for seasonal H1N1, H3N2, pandemic H1N1, and B, and 200 copies vRNA/microL of sample for H5. The analytical sensitivity of the Respiratory Panel was as follows: 10 - 150 copies vRNA/microL of sample for most of the viral targets tested in this panel except RSV (400 copies vRNA/microL of sample). No cross reactivity was observed for both panels. As determined by commercial multi-PCR kit and conventional PCR (for HBoV and WUPyV), the diagnostic sensitivity of the Respiratory Panel for each viral targets ranged from 50.0% to 100.0%, the diagnostic specificity was 96.2%-100.0%, and accordance rate was 93.2% - 100.0%, the kappa correlation of eight viral targets was > 0.75. Two liquid chip assay panels, developed based on xMAP technology, can detect 5 types/subtypes of influenza viruses and 14 respiratory viruses simultaneously in one reaction in 6 hours. They are potentially rapid, sensitive, specific, and high throughput diagnostic tools for major viral pathogens associated with respiratory tract infection.

BK and JC virus: A review

Polyomaviruses are ubiquitous, species-specific viruses belonging to the family Papovaviridae. The two most commonly known human polyomaviruses, BK virus and JC virus were first described in the 1970s. Newer human polyomaviruses, namely KI polyoma virus, WU polyoma virus and Merkel cell polyoma virus were identified in the last five years. Most humans encounter BK and JC virus during childhood, causing mild illness. However, when reactivated or acquired in the immunocompromised host, BK and JC virus have been implicated in a number of human clinical disease states. BK is most commonly associated with renal involvement, such as ureteral stenosis, hemorrhagic cystitis and nephropathy. Less commonly, it is associated with pneumonitis, retinitis, liver disease and meningoencephalitis. JC virus is most well known for its association with progressive multifocal leukoencephalopathy, and is possibly implicated in the development of various human neoplasms. The following chapter will outline the basic virology, epidemiology and clinical manifestations of BK and JC virus and discuss relevant diagnostic and treatment options.

The T Antigen Locus of Merkel Cell Polyomavirus Downregulates Human Toll-Like Receptor 9 Expression

Establishment of a chronic infection is a key event in virus-mediated carcinogenesis. Several cancer-associated, double-stranded DNA (dsDNA) viruses act via their oncoproteins to downregulate Toll-like receptor 9 (TLR9), a key receptor in the host innate immune response that senses viral or bacterial dsDNA. A novel oncogenic virus, Merkel cell polyomavirus (MCPyV), has been recently identified that causes up to 80% of Merkel cell carcinomas (MCCs). However, it is not yet known whether this oncogenic virus also disrupts immune-related pathways. We find that MCPyV large T antigen (LT) expression downregulates TLR9 expression in epithelial and MCC-derived cells. Accordingly, silencing of LT expression results in upregulation of mRNA TLR9 levels. In addition, small T antigen (sT) also appears to inhibit TLR9 expression, since inhibition of its expression also resulted in an increase of TLR9 mRNA levels. LT inhibits TLR9 expression by decreasing the mRNA levels of the C/EBPβ transactivator, a positive regulator of the TLR9 promoter. Chromatin immunoprecipitation reveals that C/EBPβ binding at a C/EBPβ response element (RE) in the TLR9 promoter is strongly inhibited by expression of MCPyV early genes and that mutation of the C/EBP RE prevents MCPyV downregulation of TLR9. A survey of BK polyomavirus (BKPyV), JC polyomavirus (JCPyV), KI polyomavirus (KIPyV), MCPyV, simian virus 40 (SV40), and WU polyomavirus (WUPyV) early genes revealed that only BKPyV and MCPyV are potent inhibitors of TLR9 gene expression. MCPyV LT targeting of C/EBP transactivators is likely to play an important role in viral persistence and potentially inhibit host cell immune responses during MCPyV tumorigenesis.

Metagenomic Detection of Viruses in Aerosol Samples from Workers in Animal Slaughterhouses

Published studies have shown that workers in animal slaughterhouses are at a higher risk of lung cancers as compared to the general population. No specific causal agents have been identified, and exposures to several chemicals have been examined and found to be unrelated. Evidence suggests a biological aetiology as the risk is highest for workers who are exposed to live animals or to biological material containing animal faeces, urine or blood. To investigate possible biological exposures in animal slaughterhouses, we used a metagenomic approach to characterise the profile of organisms present within an aerosol sample. An assessment of aerosol exposures for individual workers was achieved by the collection of personal samples that represent the inhalable fraction of dust/bioaerosol in workplace air in both cattle and sheep slaughterhouses. Two sets of nine personal aerosol samples were pooled for the cattle processing and sheep processing areas respectively, with a total of 332,677,346 sequence reads and 250,144,492 sequence reads of 85 bp in length produced for each. Eukaryotic genome sequence was found in both sampling locations, and bovine, ovine and human sequences were common. Sequences from WU polyomavirus and human papillomavirus 120 were detected in the metagenomic dataset from the cattle processing area, and these sequences were confirmed as being present in the original personal aerosol samples. This study presents the first metagenomic description of personal aerosol exposure and this methodology could be applied to a variety of environments. Also, the detection of two candidate viruses warrants further investigation in the setting of occupational exposures in animal slaughterhouses.

Rare and Emerging Viral Infections in Transplant Recipients

Emerging viral pathogens include newly discovered viruses as well as previously known viruses that are either increasing, or threatening to increase in incidence. While often first identified in the general population, they may affect transplant recipients, in whom their manifestations may be atypical or more severe. Enhanced molecular methods have increased the rate of viral discovery but have not overcome the problem of demonstrating pathogenicity. At the same time, improved clinical diagnostic methods have increased the detection of reemerging viruses in immunocompromised patients. In this review, we first discuss viral diagnostics and the developing field of viral discovery and then focus on rare and emerging viruses in the transplant population: human T-cell leukemia virus type 1; hepatitis E virus; bocavirus; KI and WU polyomaviruses; coronaviruses HKU1 and NL63; influenza, H1N1; measles; dengue; rabies; and lymphocytic choriomeningitis virus. Detection and reporting of such rare pathogens in transplant recipients is critical to patient care and improving our understanding of posttransplant infections.

The human polyomaviruses KI and WU: virological background and clinical implications

In 2007, two novel polyomaviruses KI and WU were uncovered in the respiratory secretions of children with acute respiratory symptoms. Seroepidemiological studies showed that infection by these viruses is widespread in the human population. Following these findings, different biological specimens and body compartments have been screened by real-time PCR in the attempt to establish a pathogenetic role for KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) in human diseases. Although both viruses have been found mainly in respiratory tract samples of immunocompromised patients, a clear causative link with the respiratory disease has not been established. Indeed, the lack of specific clinical or radiological findings, the frequent co-detection with other respiratory pathogens, the detection in subjects without signs or symptoms of respiratory disease, and the variability of the viral loads measured did not allow drawing a definitive conclusion. Prospective studies carried out on a large sample size including both immunocompromised and immunocompetent patients with and without respiratory symptoms are needed. Standardized quantitative real-time PCR methods, definition of a clear clinical cutoff value, timing in the collection of respiratory samples, are also crucial to understand the pathogenic role, if any, of KIPyV and WUPyV in human pathology.

Monitoring of viral pathogens in pediatric intensive care unit and analysis of clinical significance

To study the characteristics of viral spectrum and clinical features of children in pediatric intensive care unit (PICU). Nasopharyngeal aspirate specimens (NPA) from 349 patients(1 from each) and 130 cerebrospinal fluids (CSF) specimens were collected from children who were admitted to the PICU of Second Affiliated Hospital of Shantou University Medical College. Additional 87 NPA specimens were collected from healthy children for routine examination on the physical examination center, and the clinical data were collected. Multiplex PCR was applied to detect 16 kinds of viruses from NPA and CSF. Fluorescence quantitative PCR was applied to detect 13 viruses from CSF and to analyze the clinical data of positive cases. There were 209 samples (59.9%) of the 349 NPA specimens were positive for viruses, which included 117 cases positive for human rhinovirus (HRV), 60 for respiratory syncytial virus (RSV), 20 for influenza virus A (Inf A), 10 for adenovirus (ADV), 6 for parainfluenza virus type 3(PIV-3), 6 for human Boca virus (HBoV), 5 for influenza virus C(Inf C), 4 for parainfluenza virus type 4(PIV-4), 4 for human coronavirus-HKU1/OC43, 3 for influenza virus B (Inf B), 3 for WU Polyomavirus (WUPyV), 2 parainfluenza virus type 1(PIV-1), 2 human metapneumovirus (HMPV) and 1 human coronavirus-NL63/229E. But none from 87 healthy controls were positive for any respiratory virus. Among the 130 CSF specimens, in 58 cases the diagnosis was viral encephalitis. There were 22 samples (37.9%) among the 58 CSF specimens positive for viruses, which included 14 enterovirus (EV), 3 human cytomegalovirus (HCMV), 2 mumps virus, 1 coxsackie virus A16 (Cox-A16), 1 herpes simplex virus (HSV) and 1 human rhinovirus (HRV). The total positive rate was 63.3% (221/349) . Co-infection by at least 2 viral pathogens under study was observed in 45 of the 349 patients (12.9% of the total number of cases, 20.4% of the positives cases). The commonest pathogens in co-infected samples were WUPyV (100%) and HMPV(100%). The positive rate of virus peaked in the first 6 months of life, the rate in boys were higher than in girls and the peak season was summer. The numbers of none serious cases in the virus positive group were less than those in the virus negative group while the numbers of extremely serious cases in the virus positive group were higher than in the virus negative group. Viral pathogen is a major cause of infectious disease in pediatric critical illnesses and virus infection may lead to severe illness.

Molecular epidemiology of KI and WU polyomaviruses in healthy blood donors, south‐eastern France

The epidemiology of human polyomaviruses KI (KIPyV) and WU (WUPyV) in healthy populations is described poorly in the literature. The frequency of KIPyV and WUPyV viraemia was evaluated in a cohort of blood donors from south-eastern France. Plasma samples (n=640) were investigated for the presence of KIPyV/WUPyV DNA using a conserved real-time PCR detection system (VP2 gene). Three plasma samples (3/640; ∼0.5%) exhibited a positive fluorescence signal, with a low viral load (<500 copies/ml plasma); no additional amplicons were identifiable by agarose gel analysis. Sequencing highlighted the KIPyV origin of the three amplified sequences and the occurrence of point mutations. The sustained detection of KIPyV DNA in two serial samples (9 months) was in favor of a possible persistence of the virus in blood of healthy individuals. Further studies will be needed in order to explore both the prevalence and potential clinical impact of KIPyV/WUPyV on infected hosts.

The Novel KI, WU and MC Polyomaviruses and Human Diseases

From 2007 to 2012, the Polyomaviridae family expanded with the discovery of several novel human polyomaviruses. Infection by polyomaviruses is widespread in the human population, but only immunocompromised patients are at risk for disease. Currently, four polyomaviruses have been specifically associated with human diseases: BK polyomavirus, JC polyomavirus, Merkel cell polyomavirus and trichodysplasia spinulosa-associated polyomavirus. The pathogenic potential of the other human polyomaviruses is unknown. This review focuses on the novel Karolinska Institute polyomavirus, Washington University polyomavirus and Merkel cell polyomavirus. Karolinska Institute polyomavirus and Washington University polyomavirus were uncovered in respiratory specimens of children with acute respiratory symptoms. Merkel cell polyomavirus was found in an aggressive skin tumor named Merkel cell carcinoma. The scientific literature concerning the three human polyomaviruses is summarized and discussed including seroepidemiology, detection methods (real-time PCR), histopathological findings and association with clinical manifestations.

Monitoring of KI and WU polyomaviruses in hematopoietic stem cell transplant patients

Primary infection with KIPyV and WUPyV polyomaviruses occurs early in childhood followed by lifelong persistence in the body. Polyomavirus reactivation can occur in the presence of impaired immunity as in hematological malignancies or during immunosuppresssion induced by medications. In this study, reactivation of KIPyV and WUPyV was monitored by conventional PCR in plasma samples of 26 stem cell transplant patients and in 26 related bone marrow donors. Plasma samples from transplant patients were collected immediately after the end of conditioning regimen and up to 270 days after transplant. All plasma samples from transplant patients were negative for KIPyV and WUPyV DNA. Instead, KIPyV DNA was detected in two bone marrow donors. There was no evidence of KIPyV transmission from the donor to the recipient. The data suggest that detection of KIPyV in plasma is sporadic and that KPIyV and WUPyV do not affect the post-transplant clinical course. However, further studies on a larger sample size and more sensitive PCR methods are needed to confirm these observations.

Detection and quantification of classic and emerging viruses by skimmed-milk flocculation and PCR in river water from two geographical areas

Molecular techniques and virus concentration methods have shown that previously unknown viruses are shed by humans and animals, and may be transmitted by sewage-contaminated water. In the present study, 10-L river-water samples from urban areas in Barcelona, Spain and Rio Janeiro, Brazil, have been analyzed to evaluate the viral dissemination of human viruses, validating also a low-cost concentration method for virus quantification in fresh water. Three viral groups were analyzed: (i) recently reported viruses, klassevirus (KV), asfarvirus-like virus (ASFLV), and the polyomaviruses Merkel cell (MCPyV), KI (KIPyV) and WU (WUPyV); (ii) the gastroenteritis agents noroviruses (NoV) and rotaviruses (RV); and (iii) the human fecal viral indicators in water, human adenoviruses (HAdV) and JC polyomaviruses (JCPyV). Virus detection was based on nested and quantitative PCR assays. For KV and ASFLV, nested PCR assays were developed for the present study. The method applied for virus concentration in fresh water samples is a one-step procedure based on a skimmed-milk flocculation procedure described previously for seawater. Using spiked river water samples, inter- and intra-laboratory assays showed a viral recovery rate of about 50% (20–95%) for HAdV, JCPyV, NoV and RV with a coefficient of variation ≤50%. HAdV and JCPyV were detected in 100% (12/12) of the river samples from Barcelona and Rio de Janeiro. Moreover, NoV GGII was detected in 83% (5/6) and MCPyV in 50% (3/6) of the samples from Barcelona, whereas none of the other viruses tested were detected. NoV GGII was detected in 33% (2/6), KV in 33% (2/6), ASFLV in 17% (1/6) and MCPyV in 50% (3/6) of the samples from Rio de Janeiro, whereas KIPyV and WUPyV were not detected. RV were only analyzed in Rio de Janeiro and resulted positive in 67% (4/6) of the samples. The procedure applied here to river water represents a useful, straightforward and cost-effective method that could be applied in routine water quality testing. The results of the assays expand our understanding of the global distribution of the viral pathogens studied here and their persistence in the environment.

Common WU polyomavirus infection in a Beijing population indicated by surveillance for serum IgG antibody against capsid protein VP2

BackgroundWU polyomavirus (WU virus) was identified as a novel polyomavirus in 2007 from specimens of pediatric patients with acute respiratory infection (ARI). A lack of permissive cell lines has limited investigations into WU virus pathogenesis and prevalence.MethodsThe encoding region of the capsid protein VP2 gene was amplified from a WU virus DNA-positive clinical specimen and expressed as a recombinant Histagged protein in Escherichia coli BL21 (DE3). The expressed VP2 was identified by expected molecular weight and immunoreactivity with anti-His monoclonal antibody in Western blotting assay. Serum samples collected from 455 individuals of all ages in Beijing without symptoms of ARI were tested for IgG antibodies against the affinity-purified recombinant VP2 protein by Western blotting to investigate the prevalence of natural WU virus infection. In addition, serum samples from four ARI pediatric patients, whose nasopharyngeal aspirates were positive for WU virus DNA and negative for all other respiratory-related viruses, were tested for IgM antibody against the recombinant VP2.ResultsOf the 455 serum samples, 238 reacted with the recombinant VP2, yielding an overall positive rate of 52.3% for IgG against VP2 of WU virus. The positive rate was the highest in serum samples from infants and children between 1 to 4 years of age. One of four ARI pediatric patients was positive for IgM against WU virus VP2, implicating WU virus as the causative disease agent.ConclusionsThe high prevalence of IgG against WU polyomavirus in Beijing-based study population indicates that WU virus infection is common in Beijing. WU virus may be responsible for some pediatric ARI cases, and primary infection of this virus may occur mostly in childhood.

The role of infections and coinfections with newly identified and emerging respiratory viruses in children

Acute respiratory infections are a major cause of morbidity in children both in developed and developing countries. A wide range of respiratory viruses, including respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza viruses (PIVs), adenovirus, rhinovirus (HRV), have repeatedly been detected in acute lower respiratory tract infections (LRTI) in children in the past decades. However, in the last ten years thanks to progress in molecular technologies, newly discovered viruses have been identified including human Metapneumovirus (hMPV), coronaviruses NL63 (HcoV-NL63) and HKU1 (HcoV-HKU1), human Bocavirus (HBoV), new enterovirus (HEV), parechovirus (HpeV) and rhinovirus (HRV) strains, polyomaviruses WU (WUPyV) and KI (KIPyV) and the pandemic H1N1v influenza A virus. These discoveries have heavily modified previous knowledge on respiratory infections mainly highlighting that pediatric population is exposed to a variety of viruses with similar seasonal patterns. In this context establishing a causal link between a newly identified virus and the disease as well as an association between mixed infections and an increase in disease severity can be challenging. This review will present an overview of newly recognized as well as the main emerging respiratory viruses and seek to focus on the their contribution to infection and co-infection in LRTIs in childhood.

Associations between Pathogens in the Upper Respiratory Tract of Young Children: Interplay between Viruses and Bacteria

BackgroundHigh rates of potentially pathogenic bacteria and respiratory viruses can be detected in the upper respiratory tract of healthy children. Investigating presence of and associations between these pathogens in healthy individuals is still a rather unexplored field of research, but may have implications for interpreting findings during disease.Methodology/Principal FindingsWe selected 986 nasopharyngeal samples from 433 6- to 24-month-old healthy children that had participated in a randomized controlled trial. We determined the presence of 20 common respiratory viruses using real-time PCR. Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus were identified by conventional culture methods. Information on risk factors was obtained by questionnaires. We performed multivariate logistic regression analyses followed by partial correlation analysis to identify the overall pattern of associations. S. pneumoniae colonization was positively associated with the presence of H. influenzae (adjusted odds ratio 1.60, 95% confidence interval 1.18–2.16), M. catarrhalis (1.78, 1.29–2.47), human rhinoviruses (1.63, 1.19–2.22) and enteroviruses (1.97, 1.26–3.10), and negatively associated with S. aureus presence (0.59, 0.35–0.98). H. influenzae was positively associated with human rhinoviruses (1.63, 1.22–2.18) and respiratory syncytial viruses (2.78, 1.06–7.28). M. catarrhalis colonization was positively associated with coronaviruses (1.99, 1.01–3.93) and adenoviruses (3.69, 1.29–10.56), and negatively with S. aureus carriage (0.42, 0.25–0.69). We observed a strong positive association between S. aureus and influenza viruses (4.87, 1.59–14.89). In addition, human rhinoviruses and enteroviruses were positively correlated (2.40, 1.66–3.47), as were enteroviruses and human bocavirus, WU polyomavirus, parainfluenza viruses, and human parechovirus. A negative association was observed between human rhinoviruses and coronaviruses.Conclusions/SignificanceOur data revealed high viral and bacterial prevalence rates and distinct bacterial-bacterial, viral-bacterial and viral-viral associations in healthy children, hinting towards the complexity and potential dynamics of microbial communities in the upper respiratory tract. This warrants careful consideration when associating microbial presence with specific respiratory diseases.

WU and KI Polyomaviruses in Respiratory Samples from Allogeneic Hematopoietic Cell Transplant Recipients

Data are limited regarding 2 new human polyomaviruses, KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV), in immunocompromised patients. We used real-time PCR to test for these and 12 respiratory viruses in 2,732 nasal wash samples collected during the first year after allogeneic hematopoietic cell transplantation from 222 patients. Specimens were collected weekly until day 100; then at least every 3 months. One year after hematopoietic cell transplantation, the cumulative incidence estimate was 26% for KIPyV and 8% for WUPyV. Age <20 years predicted detection of KIPyV (hazard ratio [HR] 4.6) and WUPyV (HR 4.4), and detection of a respiratory virus in the previous 2 weeks predicted KIPyV detection (HR 3.4). Sputum production and wheezing were associated with detection of KIPyV in the past week and WUPyV in the past month. There were no associations with polyomavirus detection and acute graft versus host disease, cytomegalovirus reactivation, neutropenia, lymphopenia, hospitalization, or death.

Novel human polyomaviruses in pregnancy: Higher prevalence of BKPyV, but no WUPyV, KIPyV and HPyV9

BackgroundImmunosuppression due to pregnancy may lead to higher susceptibility to infections and reactivation of latent infections, such as BK polyomavirus (BKPyV). There is lack of information about the prevalence of novel human polyomavirus 9 (HPyV9), WU (WUPyV) and KI (KIPyV) during pregnancy. ObjectivesTo study whether pregnancy results in higher prevalence of HPyV9, WUPyV, KIPyV and their correlation with BKPyV. Study designPlasma, urine and throat swab samples from 100 pregnant and 100 non pregnant women were screened for the presence of WUPyV, KIPyV, HPyV9 and BKPyV by PCR. ResultsNo WUPyV DNA was detected in plasma, urine and respiratory samples from pregnant and non pregnant women. KIPyV DNA was found in two plasma samples from non pregnant women (2%) and not detected in other samples from neither pregnant nor non pregnant women. HPyV9 DNA was determined in all sample types of pregnant and non pregnant women, respectively. There were no significant differences between pregnant and non pregnant women in HPyV9 DNA frequencies for plasma (2% vs. 6%), urine (3% vs. 2%) and respiratory samples (2% vs. 2%). Prevalence of BKPyV in urine samples was significantly higher (p=0.039) in pregnant women (13%) then in non pregnant women (4%); co infection with KIPyV and/or HPyV9 was not detected. ConclusionsIn contrast with BKPyV, infection with WUPyV, KIPyV and HPyV9 was not detected more frequently during pregnancy. To the best of our knowledge HPyV9 was detected first in respiratory samples in our study.

Immunotherapy for Polyomaviruses: Opportunities and Challenges

Polyomaviruses are small DNA viruses present in mammals and birds, and in 1953 the first one to be described was murine polyomavirus. It was not until 1971 that the first two human polyomaviruses (HPyVs), BK virus and JC virus, were discovered and found to be common in humans, but only associated with disease in severely immunosuppressed patients. Since 2007, seven new HPyVs have been identified: KI polyomavirus, WU polyomavirus, Merkel cell polyomavirus, HPyV6, HPyV7, trichodyplasia spinulosa polyomavirus and HPyV9. Notably, Merkel cell polyomavirus was detected in Merkel cell cancer, a tumor mainly found in elderly and immunocompromised individuals, while trichodyplasia spinulosa polyomavirus was found in trichodyplasia spinulosa, a skin disorder observed only in immunosuppressed individuals. Consequently, many polyomaviruses cause problems in immunosuppressed individuals. This review deals with these issues, and the potential of the capsid protein VP1 to form virus-like particles for use as vaccines against polyomavirus infections.

New respiratory viral infections

The first era in the discoveries of respiratory viruses occured between 1933 and 1965 when influenza virus, enteroviruses, adenovirus, respiratory syncytial virus, rhinovirus, parainfluenza virus and coronavirus (CoV) were found by virus culture. In the 1990s, the development of high throughput viral detection and diagnostics instruments increased diagnostic sensitivity and enabled the search for new viruses. This article briefly reviews the clinical significance of newly discovered respiratory viruses. In 2001, the second era in the discoveries of respiratory viruses began, and several new respiratory viruses and their subgroups have been found: human metapneumovirus, CoVs NL63 and HKU1, human bocavirus and human rhinovirus C and D groups. Currently, a viral cause of pediatric respiratory illness is identifiable in up to 95% of cases, but the detection rates decrease steadily by age, to 30-40% in the elderly. The new viruses cause respiratory illnesses such as common cold, bronchitis, bronchiolitis, exacerbations of asthma and chronic obstructive pulmonary disease and pneumonia. Rarely, acute respiratory failure may occur. The clinical role of other new viruses, KI and WU polyomaviruses and the torque teno virus, as respiratory pathogens is not clear.

Detection of WU polyomavirus in children with low respiratory tract infections using real-time fluorescent quantitative PCR

Development and application of a real time fluorescent quantitative PCR (FQ-PCR) assay for detecting WU polyomavirus in children with low respiratory tract infections. The VP2 gene of WU polyomavirus was selected as the detection target, from which the real time primers and probes were designed. The standard curve was established by using recombinant plasmid as template. And the FQ-PCR assay for specific detection of WU polyomavirus was established. The specificity, sensitivity and reproducibility of the method were evaluated. Furthermore, the clinical specimens from children with respiratory tract infections collected in Wenling First People's Hospital were quantitatively detected using this method. In this study, the FQ-PCR method was established to detect a specific fragment in VP2gene of WU polyomavirus. The standard curve coefficient R2 was 0.998. And this method can detect as low as 50 copies recombinant plasmid. The clinical specimens of sputum and throat swab from children with respiratory tract infections were quantitatively detected using this method. 7 sputum specimens were detected as WU polyomavirus positive in 700 sputum specimens, the positive ratio was 1.00%. No positive specimens were detected in 146 specimens of throat swabs and 846 blood samples from same patient population. The results indicated that the FQ-PCR assay method established in this study was specific, rapid and sensitive for detecting WU polyomavirus in children with lower respiratory tract infections. The sputum specimen is more suitable to be used for gene detection of WU polyomavirus than throat swab or blood.