Human parainfluenza virus-associated respiratory tract infection among children and genetic analysis of HPIV-3 strains in Beijing, China

Development of Primer Panels for Amplicon Sequencing of Human Parainfluenza Viruses Type 1 and 2

Human parainfluenza viruses (hPIVs) are major contributors to respiratory tract infections in young children worldwide. Despite their global significance, genomic surveillance of hPIV1 and hPIV2 had not previously been conducted in Russia. This study aimed to develop a robust amplicon-based sequencing protocol for these viruses. The designed primer sets were tested on clinical samples containing hPIV RNA to evaluate their performance and efficiency. Sequencing results demonstrated high-quality genome data and efficient amplification across various Ct values. As a result, 41 hPIV1 and 13 hPIV2 near-complete genome sequences were successfully obtained from clinical specimens collected in Saint Petersburg (Russia). Phylogenetic analysis of the HN gene sequences showed that Russian hPIV1 strains clustered into clades II and III, while hPIV2 strains were distributed between clusters G1a and G3. The whole-genome-based trees confirmed the same distribution of the strains. These findings highlight the potential of our primer panels and contribute to a better understanding of the molecular characteristics and phylogenetic diversity of circulating hPIV strains. Notably, this study presents the first evolutionary analysis of hPIVs in Russia.

Epidemiological, Clinical, and Genomic Traits of PIV in Hospitalized Children After the COVID-19 Pandemic in Wuhan, China

Human parainfluenza virus (PIV) is a main cause of acute lower respiratory tract infections (ALRTIs), which contributes to childrens' mortality worldwide; however, the epidemiology of PIVs following the SARS-CoV-2 pandemic is still not clarified, and poses risks of potential outbreaks. Herein, we conducted a retrospective observational study from September 26, 2020 to September 30, 2023 to assess PIV epidemiology in Wuhan, China, as well as the clinical characteristics of PIV infections. In total, 14,065 inpatients with ALRTIs were enrolled, of which 936 were identified to have PIV infection. We also obtained 69 PIV3 RNA to reveal its molecular traits. An alteration in PIV season pattern away from spring and summer prevalence was noted, as well as a progressive rise in its detection rate. PIV-related ALRTIs were more prevalent in male patients. PIV3 was the dominant PIV type in recent years. In comparison with the phase before the cancellation of Dynamic Zero-COVID Policy in December 2022, symptoms after its repeal were milder. All Wuhan strains were classified with C3f lineage and possibly evolved from native strains in China. Additionally, some mutations, such as Q499P in protein hemagglutinin-neuraminidase, should be given further attention. In summary, our study demonstrates the clinical characteristics of PIVs and genomic traits of PIV3 in Wuhan, China, thus holds importance for the diagnosis and control of PIV infections in the post-pandemic era.

Genetic characteristics of human parainfluenza viruses 1-4 associated with acute lower respiratory tract infection in Chinese children, during 2015-2021

Human parainfluenza viruses (HPIVs) are a significant cause of acute lower respiratory tract infections (ALRTIs) among young children and elderly individuals worldwide. The four types of HPIVs (HPIV1-4) can cause recurrent infections and pose a significant economic burden on health care systems globally. However, owing to the limited availability of complete genome sequences, the genetic evolution of these viruses and the development of vaccines and antiviral treatments are hampered. To address this issue, this study utilized next-generation sequencing to obtain 156 complete genome sequences of HPIV1-4, which were isolated from hospitalized children with ALRTIs in six regions of China between 2015 and 2021. This study revealed multiple clades, lineages, or sublineages of HPIVs circulating in mainland China, with a novel clade D of HPIV1 identified as geographically restricted to China. Moreover, this study identified the endemic dominant genotype of HPIV3, lineage C3, which has widely spread and continuously circulated in China. Bioinformatic analysis of the genome sequences revealed that the proteins of HPIV3 possessed the most variable sites, with the P protein showing more diversity than the other proteins among all types of HPIVs. The HN proteins of HPIV1-3 are all under negative/purifying selection, and two amino acid substitutions in the HN proteins correspond to known mAb neutralizing sites in the two HPIV3 strains. These findings provide crucial insights into the genetic diversity and evolutionary dynamics of HPIVs circulating among children in China and may facilitate research on the molecular diagnosis, vaccine development, and surveillance of HPIVs.IMPORTANCEPhylogenetic analysis revealed the prevalence of multiple clades, lineages, or sublineages of human parainfluenza viruses (HPIVs) circulating in mainland China. Notably, a unique evolutionary branch of HPIV1 containing only Chinese strains was identified and designated clade D. Furthermore, in 2023, HPIV3 strains from Pakistan and Russia formed a new lineage within clade C, named C6. The first HPIV4b sequence obtained in this study from China belongs to lineage C2. Evolutionary rate assessments revealed that both the HN and whole-genome sequences of HPIV3 presented the lowest evolutionary rates compared with those of the other HPIV types, with rates of 6.98E-04 substitutions/site/year (95% HPD: 5.87E-04 to 8.25E-03) and 5.85E-04 substitutions/site/year (95% HPD: 5.12E-04 to 6.62E-04), respectively. Recombination analysis revealed a potential recombination event in the F gene of an HPIV1 strain in this study. Additionally, all the newly obtained HPIV1-3 strains exhibited negative selection pressure, and two mutations were identified in the HN protein of two HPIV3 strains at monoclonal antibody-binding sites.

Molecular Evolutionary Analyses of the Fusion Genes in Human Parainfluenza Virus Type 4

The human parainfluenza virus type 4 (HPIV4) can be classified into two distinct subtypes, 4a and 4b. The full lengths of the fusion gene (F gene) of 48 HPIV4 strains collected during the period of 1966-2022 were analyzed. Based on these gene sequences, the time-scaled evolutionary tree was constructed using Bayesian Markov chain Monte Carlo methods. A phylogenetic tree showed that the first division of the two subtypes occurred around 1823, and the most recent common ancestors of each type, 4a and 4b, existed until about 1940 and 1939, respectively. Although the mean genetic distances of all strains were relatively wide, the distances in each subtype were not wide, indicating that this gene was conserved in each subtype. The evolutionary rates of the genes were relatively low (4.41 × 10-4 substitutions/site/year). Moreover, conformational B-cell epitopes were predicted in the apex of the trimer fusion protein. These results suggest that HPIV4 subtypes diverged 200 years ago and the progenies further diverged and evolved.

Molecular Epidemiology of Human Parainfluenza Virus Type 3 in Children With Acute Respiratory Tract Infection in Hangzhou

BACKGROUND

Since the outbreak of COVID-19, China has undertaken a variety of preventative and control measures, effectively reducing the incidence of numerous infectious diseases among the pediatric population in Hangzhou. We aim to investigate the genetic and epidemiological characteristics of Human parainfluenza virus-3 (HPIV-3) in pediatric patients during this period.

METHODS

A total of 1442 pharyngeal swab samples were collected from outpatients and inpatients with a diagnosis of acute respiratory tract infections (ARTIs) from November 2020 to March 2021. HPIV-3 was detected by quantitative real time polymerase chain reaction (qRT-PCR). The L gene of HPIV-3 positive samples was amplified and sequenced.

RESULTS

Among 1442 children with ARTI, the positive rate of HPIV-3 was 7.07% (102/1442). The positive detection rate was the highest in the 6-month to 1-year age group. Coinfection was observed in 36 HPIV-3-positive samples (35.29%, 36/102), and adenovirus (ADV) was the most common coinfecting virus (63.89%, 23/36). The L gene of 48 HPIV-3 positive samples was sequenced. The nucleotide sequence analysis showed high consistency (92.10%-99.40%), and all strains belonged to C3a.

CONCLUSIONS

During study periods, the positive detection rate of HPIV-3 among children is high, and the highest proportion of coinfection was observed in HPIV-3 mixed ADV infection. Phylogenetic analysis revealed that the nucleotide sequence of the L gene of HPIV-3 was highly consistent, and the main epidemic strain in this area was the C3a subtype.

Genetic analysis of human parainfluenza type 2 virus in Riyadh, Saudi Arabia

The extensive mass gathering of pilgrims from all over the world, as well as the constant flow of foreign workers via country entry crossings, raises the likelihood of respiratory virus outbreaks spreading and evolving in Saudi Arabia. Here, we report the sequence and phylogenetic analysis of the human parainfluenza type-2 (HPIV-2) in nasopharyngeal aspirates (NPAs) collected from Riyadh, Saudi Arabia, from 2020/21 to 2021/22 seasons. RNA was extracted from the clinical samples and subjected to RT-PCR analysis for the detection of IAV and IBV. The full-length HN gene of HPIV-2 was amplified and sequenced. Multiple sequence alignments (both nucleotides and deduced amino acids) were aligned using Clustal W, MegAlign program of Lasergene software, and MEGA 7.0. HPIV-2 was found in (4; 2% of 200) NPAs. Sequence and phylogenetic analysis results showed that indicated a genotype shifting from G3 to G4a with 83% sequence homology 62-M786 from Japan, which was prominent throughout the winter seasons of 2008/09. Multiple amino acid sequence alignment revealed 25 sites of possible difference between G3 genotypes and G4a. A total of twenty- two of these locations were shared by the other G4a genotypes, whereas three positions, 67 V, 175 S, and 377Q, were exclusively shared by G3. Only eight conserved N-glycosylation sites were found at amino acids 6(NLS), 286(NTT), 335(NIT), 388(NNS), 498(NES), 504(NPT), 517(NTT), and 539(NGT) in four Riyadh isolates. Our findings also revealed that the G4a genotype of HPIV-2 predominated in our samples population during the winter seasons of 2020/21 and 2021/22. Further research with a larger sample size covering numerous regions of Saudi Arabia throughout different epidemic seasons is needed to achieve an improved knowledge of HPIV-2 circulation.

Human Parainfluenza Virus (HPIV) Detection in Hospitalized Children with Acute Respiratory Tract Infection in the Western Cape, South Africa during 2014-2022 Reveals a Shift in Dominance of HPIV 3 and 4 Infections

The epidemiology of human parainfluenza viruses (HPIV), particularly its role as a cause of acute respiratory infection (ARI) in infants, has not been formally studied in South Africa. We evaluated HPIV prevalence in diagnostic samples from hospitalized children from public sector hospitals in the Western Cape between 2014 and 2022. HPIV infection was detected in 2-10% of patients, with the majority of infections detected in children less than 1 year of age. Prior to 2020, HPIV 4 (40%) and HPIV 3 (34%) were the most prevalent types, with seasonal peaks in late winter/spring for HPIV 3 and autumn/winter for HPIV 4. HPIV 4A and 4B co-circulated during the seasonal activity between 2014 and 2017. Pandemic restrictions in 2020 had a profound effect on HPIV circulation and the rebound was dominated by waves of HPIV 3, accounting for 66% of detections and a sustained decline in the circulation of HPIV 1, 2 and 4. An immunity gap could account for the surge in HPIV 3 infections, but the decline in prior HPIV 4 dominance is unexplained and requires further study.

Molecular evolutionary analyses of the fusion protein gene in human respirovirus 1

Few evolutionary studies of the human respiratory virus (HRV) have been conducted, but most of them have focused on HRV3. In this study, the full-length fusion (F) genes in HRV1 strains collected from various countries were subjected to time-scaled phylogenetic, genome population size, and selective pressure analyses. Antigenicity analysis was performed on the F protein. The time-scaled phylogenetic tree using the Bayesian Markov Chain Monte Carlo method estimated that the common ancestor of the HRV1 F gene diverged in 1957 and eventually formed three lineages. Phylodynamic analyses showed that the genome population size of the F gene has doubled over approximately 80 years. Phylogenetic distances between the strains were short (< 0.02). No positive selection sites were detected for the F protein, whereas many negative selection sites were identified. Almost all conformational epitopes of the F protein, except one in each monomer, did not correspond to the neutralising antibody (NT-Ab) binding sites. These results suggest that the HRV1 F gene has constantly evolved over many years, infecting humans, while the gene may be relatively conserved. Mismatches between computationally predicted epitopes and NT-Ab binding sites may be partially responsible for HRV1 reinfection and other viruses such as HRV3 and respiratory syncytial virus.

Parainfluenza virus infections in patients with hematological malignancies or stem cell transplantation: Analysis of clinical characteristics, nosocomial transmission and viral shedding

To assess morbidity and mortality of parainfluenza virus (PIV) infections in immunocompromised patients, we analysed PIV infections in a hematology and stem cell transplantation (SCT) unit over the course of three years. Isolated PIV strains were characterized by sequence analysis and nosocomial transmission was assessed including phylogenetic analysis of viral strains. 109 cases of PIV infection were identified, 75 in the setting of SCT. PIV type 3 (n = 68) was the most frequent subtype. PIV lower respiratory tract infection (LRTI) was observed in 47 patients (43%) with a mortality of 19%. Severe leukopenia, prior steroid therapy and presence of co-infections were significant risk factors for development of PIV-LRTI in multivariate analysis. Prolonged viral shedding was frequently observed with a median duration of 14 days and up to 79 days, especially in patients after allogeneic SCT and with LRTI. Nosocomial transmission occurred in 47 patients. Phylogenetic analysis of isolated PIV strains and combination with clinical data enabled the identification of seven separate clusters of nosocomial transmission. In conclusion, we observed significant morbidity and mortality of PIV infection in hematology and transplant patients. The clinical impact of co-infections, the possibility of long-term viral shedding and frequent nosocomial transmission should be taken into account when designing infection control strategies.

Controlling a human parainfluenza virus-3 outbreak in a haematology ward in a tertiary hospital: the importance of screening strategy and molecular diagnostics in relation to clinical symptoms

BACKGROUND

Human parainfluenza 3 (HPIV-3) outbreak at the haemato-oncology ward of the Maastricht University Medical Center in the summer of 2016.

AIM

To describe an effective strategy to control the largest reported HPIV-3 outbreak at an adult haematology-oncology ward in the Netherlands by implementing infection control measures and molecular epidemiology investigation.

METHODS

Clinical, patient and diagnostic data were both pro- and retrospectively collected. HPIV-3 real-time-PCR (HPIV-3 RT-PCR) was validated using oropharyngeal rinse samples. Screening of all new and admitted patients was implemented to identify asymptomatic infection or prolonged shedding of HPIV-3 allowing cohort isolation.

FINDINGS

The HPIV-3 outbreak occurred between 9 July and 28 September 2016 and affected 53 patients. HPIV-3 RT-PCR on oropharyngeal rinse samples demonstrated an up to tenfold higher sensitivity compared to pharyngeal swabs. Monitoring showed that at first positive PCR, 20 patients (38%) were asymptomatic (of which 11 remained asymptomatic) and the average duration of shedding was 14 days (range 1-58). Asymptomatic patients had lower viral load, shorter period of viral shedding (≤14 days) and were mostly immune competent oncology patients. The outbreak was under control 5 weeks after implementation of screening of asymptomatic patients.

CONCLUSION

Implementation of a sensitive screening method identified both symptomatic and asymptomatic patients which had lower viral load and allowed early cohort isolation. This is especially important in a ward that combines patients with varying immune status, since both immunocompromised and immune competent patients are likely to spread the HPIV-3 virus, either through prolonged shedding or through asymptomatic course of disease.

POCT Detection of 14 Respiratory Viruses Using Multiplex RT-PCR

Over the past 6 years, acute respiratory infections have constituted an average of more than 70,000 cases in South Korea. It results in a high mortality rate in infants and the elderly with weak immunity. There are several types of respiratory viruses that invade the human respiratory tract and cause infectious disease. Reverse transcription PCR (RT-PCR) is mainly used for respiratory virus detection owing to its high sensitivity and reproducibility. In response, a multiplex real-time RT-PCR (rRT-PCR) assay was developed for the detection of influenza A and B viruses, parainfluenza viruses 1–4 (PIV1-4), human metapneumovirus, adenovirus, human rhinovirus, respiratory syncytial virus (RSV), and SARS-CoV-2. Detection ability of RT-PCR assay was confirmed by applying it to a portable device capable of point-of-care testing (POCT). Amplicons were synthesized using primer pairs and probe sets designed for each target virus, and a standard curve was constructed to confirm the limit of detection. An experiment using nasopharyngeal swab samples was conducted to understand the field applicability of the rRT-PCR assay. Detection was confirmed in most samples. This study demonstrated that rapid and accurate detection results can be obtained using the multiplex rRT-PCR based POC test, and that it is possible to detect 14 types of respiratory viruses that are generally difficult to distinguish at the same time, enabling timely treatment. Furthermore, we expect that the portable PCR device can significantly reduce the processing procedure of clinical samples before testing, which is the main disadvantage of common RT-PCR tests and can help reduce costs.

Genetic Characteristics of Human Parainfluenza Virus Types 1-4 From Patients With Clinical Respiratory Tract Infection in China

Human parainfluenza viruses (HPIV1–4) cause acute respiratory tract infections, thereby impacting human health worldwide. However, there are no current effective antivirals or licensed vaccines for infection prevention. Moreover, sequence information for human parainfluenza viruses (HPIVs) circulating in China is inadequate. Therefore, to shed light on viral genetic diversity and evolution, we collected samples from patients infected with HPIV1–4 in China from 2012 to 2018 to sequence the viruses. We obtained 24 consensus sequences, comprising 1 for HPIV1, 2 for HPIV2, 19 for HPIV3, and 2 for HPIV4A. Phylogenetic analyses classified the 1 HPIV1 into clade 2, and the 2 HPIV4 sequences into cluster 4A. Based on the hemagglutinin-neuraminidase (HN) gene, a new sub-cluster was identified in one of the HPIV2, namely G1c, and the 19 HPIV3 sequences were classified into the genetic lineages of C3f and C3a. The results indicated that HPIV1–4 were co-circulated in China. Further, the lineages of sub-cluster C3 of HPIV3 were co-circulated in China. A recombination analysis indicated that a putative recombination event may have occurred in the HN gene of HPIV3. In the obtained sequences of HPIV3, we found that two amino acid substitution sites (R73K in the F protein of PUMCH14028/2014 and A281V in the HN protein of PUMCH13961/2014) and a negative selection site (amino acid position 398 in the F protein) corresponded to the previously reported neutralization-related sites. Moreover, amino acid substitution site (K108E) corresponded to the negative selection site (amino acid position 108) in the 10 F proteins of HPIV3. However, no amino acid substitution site corresponded to the glycosylation site in the obtained HPIV3 sequences. These results might help in studying virus evolution, developing vaccines, and monitoring HPIV-related respiratory diseases.

Virological Surveillance and Molecular Characterization of Human Parainfluenzavirus Infection in Children with Acute Respiratory Illness: Germany, 2015-2019

Human parainfluenza viruses (HPIVs) are important causes of respiratory illness, especially in young children. However, surveillance for HPIV is rarely performed continuously, and national-level epidemiologic and genetic data are scarce. Within the German sentinel system, to monitor acute respiratory infections (ARI), 4463 respiratory specimens collected from outpatients < 5 years of age between October 2015 and September 2019 were retrospectively screened for HPIV 1-4 using real-time PCR. HPIV was identified in 459 (10%) samples. HPIV-3 was the most common HPIV-type, with 234 detections, followed by HPIV-1 (113), HPIV-4 (61), and HPIV-2 (49). HPIV-3 was more frequently associated with age < 2 years, and HPIV-4 was more frequently associated with pneumonia compared to other HPIV types. HPIV circulation displayed distinct seasonal patterns, which appeared to vary by type. Phylogenetic characterization clustered HPIV-1 in Clades 2 and 3. Reclassification was performed for HPIV-2, provisionally assigning two distinct HPIV-2 groups and six clades, with German HPIV-2s clustering in Clade 2.4. HPIV-3 clustered in C1, C3, C5, and, interestingly, in A. HPIV-4 clustered in Clades 2.1 and 2.2. The results of this study may serve to inform future approaches to diagnose and prevent HPIV infections, which contribute substantially to ARI in young children in Germany.

Genetic analysis of human parainfluenza virus type 4 associated with severe acute respiratory infection in children in Luohe City, Henan Province, China, during 2017-2018

During 2017–2018, nasopharyngeal aspirates (NPAs) from 627 hospitalized patients with severe acute respiratory infection at Luohe Center Hospital were tested by RT-PCR for human parainfluenza virus 4 (HPIV-4). Fourteen (2.2%) of the 627 samples were positive for HPIV-4. The complete HN gene was amplified from nine positive samples and sequenced. Sequence comparisons showed that the HPIV-4 strains circulating in the city of Luohe are closely related to HPIV-4A strains. Our study indicated that there were multiple lineages of HPIV-4 circulating in Henan Province in China during the study period. This will improve our understanding of the epidemiological and clinical characteristics of HPIV-4.

The landscape of extrapulmonary manifestations of human parainfluenza viruses: A systematic narrative review

Human parainfluenza virus (HPIV) infection is associated with every kind of respiratory tract illnesses, including the common cold, laryngotracheobronchitis (i.e. croup), tracheobronchitis, bronchiolitis, and pneumonia, in both children and adults. Although HPIVs are common respiratory pathogens, there are increasing reports about extrapulmonary manifestations of HPIVs infection. Each of the HPIVs could produce infection of other organs (central nervous system, heart, myocardium, etc.) in all age groups who are either immunocompetent or immunocompromised. This review aimed at summarizing the available data on clinical manifestations of HPIV infection outside the respiratory tract from 1961 to 2020. The findings support the possibility of extrapulmonary infections that were thought to be due to rare host genetic or immunologic defects in infected patients. These findings highlight the fact that extrapulmonary dissemination of HPIV can occur, but the association is not clearly demonstrated. Our data support the hypothesis that HPIV infection is one of the possible causes of these alterations and may even be the direct cause in some cases.

A review on disease burden and epidemiology of childhood parainfluenza virus infections in Asian countries

Human parainfluenza viruses (HPIVs) are an important cause of acute respiratory tract infections (ARTIs) in children less than 5 years, second only to human respiratory syncytial viruses (HRSVs). Generally, patients infected with HPIVs are treated in outpatient clinics, yet also contribute to ARTI-associated hospitalization in children. Although HPIV infections are well studied in developed countries, these infections remain under-investigated and not considered in the routine laboratory diagnosis of childhood ARTI in many developing countries in Asia. We performed an extensive literature search on the prevalence, epidemiology, and burden of HPIV infections in children less than 5 years in Asia using PubMed and PubMed Central search engines. Based on the literature, the prevalence of HPIV infection in Asia ranges from 1% to 66%. According to many studies, HPIV-3 is the major virus circulating among children; however, several studies failed to detect HPIV-4 due to unavailability of diagnostic tools. In Asian countries, HPIV contributes a substantial disease burden in children. The data in this review should assist researchers and public health authorities to plan preventive measures, including accelerating research on vaccines and antiviral drugs.

Fingerprint Biometric System Hygiene and the Risk of COVID-19 Transmission

Biometric systems use scanners to verify the identity of human beings by measuring the patterns of their behavioral or physiological characteristics. Some biometric systems are contactless and do not require direct touch to perform these measurements; others, such as fingerprint verification systems, require the user to make direct physical contact with the scanner for a specified duration for the biometric pattern of the user to be properly read and measured. This may increase the possibility of contamination with harmful microbial pathogens or of cross-contamination of food and water by subsequent users. Physical contact also increases the likelihood of inoculation of harmful microbial pathogens into the respiratory tract, thereby triggering infectious diseases. In this viewpoint, we establish the likelihood of infectious disease transmission through touch-based fingerprint biometric devices and discuss control measures to curb the spread of infectious diseases, including COVID-19.

Genetic diversity and evolutionary analysis of human respirovirus type 3 strains isolated in Kenya using complete hemagglutinin-neuraminidase (HN) gene

Human respirovirus type 3 (HRV3) is a leading etiology of lower respiratory tract infections in young children and ranks only second to the human respiratory syncytial virus (HRSV). Despite the public health importance of HRV3, there is limited information about the genetic characteristics and diversity of these viruses in Kenya. To begin to address this gap, we analyzed 35 complete hemagglutinin-neuraminidase (HN) sequences of HRV3 strains isolated in Kenya between 2010 and 2013. Viral RNA was extracted from the isolates, and the entire HN gene amplified by RT-PCR followed by nucleotide sequencing. Phylogenetic analyses of the sequences revealed that all the Kenyan isolates grouped into genetic Cluster C; sub-clusters C1a, C2, and C3a. The majority (54%) of isolates belonged to sub-cluster C3a, followed by C2 (43%) and C1a (2.9%). Sequence analysis revealed high identities between the Kenyan isolates and the HRV3 prototype strain both at the amino acid (96.5-97.9%) and nucleotide (94.3-95.6%) levels. No amino acid variations affecting the catalytic/active sites of the HN glycoprotein were observed among the Kenyan isolates. Selection pressure analyses showed that the HN glycoprotein was evolving under positive selection. Evolutionary analyses revealed that the mean TMRCA for the HN sequence dataset was 1942 (95% HPD: 1928-1957), while the mean evolutionary rate was 4.65x10-4 nucleotide substitutions/site/year (95% HPD: 2.99x10-4 to 6.35x10-4). Overall, our results demonstrate the co-circulation of strains of cluster C HRV3 variants in Kenya during the study period. This is the first study to describe the genetic and molecular evolutionary aspects of HRV3 in Kenya using the complete HN gene.

Molecular Evolution of the Fusion Protein (F) Gene in Human Respirovirus 3

To elucidate the evolution of human respirovirus 3 (HRV3), we performed detailed genetic analyses of the F gene (full-length) detected from hundreds of HRV3 strains obtained from various geographic regions. First, we performed time-scaled evolutionary analyses using the Bayesian Markov chain Monte Carlo method. Then, we performed analyses of phylodynamics, similarity, phylogenetic distance, selective pressure, and conformational B-cell epitope with the F-protein structural analyses. Time-scaled phylogenetic tree showed that the common ancestor of HRV3 and bovine respirovirus 3 diverged over 300 years ago and subdivided it into three major clusters and four subclusters during the most recent 100 years. The overall evolutionary rate was approximately 10^-3 substitutions/site/year. Indigenous similarity was seen in the present strains, and the mean phylogenetic distance were 0.033. Many negative selection sites were seen in the ectodomain. The conformational epitopes did not correspond to the neutralizing antibody binding sites. These results suggest that the HRV3 F gene is relatively conserved and restricted in this diversity to preserve the protein function, although these strains form many branches on the phylogenetic tree. Furthermore, HRV3 reinfection may be responsible for discordances between the conformational epitopes and the neutralizing antibody binding sites of the F protein. These findings contribute to a better understanding of HRV3 virology.

Molecular evolution of the hemagglutinin-neuraminidase (HN) gene in human respirovirus 3

Human respirovirus 3 (HRV3) is a major causative agent of acute respiratory infections in humans. HRV3 can manifest as a recurrent infection, although exactly how is not known. In the present study, we conducted detailed molecular evolutionary analyses of the major antigen-coding hemagglutinin-neuraminidase (HN) gene of this virus detected/isolated in various countries. We performed analyses of time-scaled evolution, similarity, selective pressure, phylodynamics, and conformational epitope prediction by mapping to HN protein models. In this way, we estimated that a common ancestor of the HN gene of HRV3 and bovine respirovirus 3 diverged around 1815 and formed many lineages in the phylogenetic tree. The evolutionary rates of the HN gene were 1.1 × 10^-3 substitutions/site/year, although the majority of these substitutions were synonymous. Some positive and many negative selection sites were predicted in the HN protein. Phylodynamic fluctuations of the gene were observed, and these were different in each lineage. Furthermore, most of the predicted B cell epitopes did not correspond to the neutralization-related mouse monoclonal antibody binding sites. The lack of a link between the conformational epitopes and neutralization sites may explain the naturally occurring HRV3 reinfection.

An Outbreak of Human Parainfluenza Virus 3 (Phylogenetic Subcluster C5) Infection among Adults at a Residential Care Facility for the Disabled in Croatia, 2018

INTRODUCTION

Although highly pertinent for children, outbreaks of human parainfluenza virus (HPIV) may cause up to 15% of all respiratory illnesses in adults and predispose them to serious adverse outcomes, with HPIV serotype 3 (HPIV3) being the most common. This study represents the first report of an HPIV3 outbreak among adults at a long-term health-care facility in Croatia.

METHODS

A retrospective study was conducted to investigate an outbreak of acute respiratory infection (ARI) at a single residential care facility for the disabled in Croatia. Demographic, epidemiological, and clinical data were collected for all residents, while hospitalized patients were appraised in detail by laboratory/radiological methods. Multiplex PCR for respiratory viruses and sequencing was performed. Partial HPIV3 HN 581 nt sequences were aligned with HPIV3 sequences from the GenBank database to conduct a phylogenetic analysis, where different bioinformatic approaches were employed.

RESULTS

In late June 2018, 5 of the 10 units at the facility were affected by the outbreak. Among the 106 residents, 23 (21.7%) developed ARI, and 6 (26.1%) of them were hospitalized. HPIV3 was identified in 18 (73%) of the residents and 5 (83%) of the hospitalized individuals. Isolated HPIV3 strains were classified within the phylogenetic subcluster C5 but grouped on 2 separate branches of the phylogenetic tree. During the entire outbreak period, none of the institution's employees reported symptoms of ARI.

CONCLUSIONS

Our study has shown that this health care-associated outbreak of HPIV3 infection could have been linked to multiple importation events. Preventive measures in curbing such incidents should be enforced vigorously.

A 28-year study of human parainfluenza in Rio Grande do Sul, Southern Brazil

PROBLEM

Human parainfluenza virus (hPIV) is an important pathogen in respiratory infections, however the health burden of hPIV is underestimated. This study describes the infections by hPIV1-3 in Rio Grande do Sul, Brazil, from 1990 to 2017, providing data of the frequency and seasonality of cases and associated clinical symptoms.

METHOD OF STUDY

Nasopharyngeal samples of patients with respiratory infection were collected, clinical data were analyzed, and immunofluorescence was used to detect hPIV.

RESULTS

Respiratory viruses were detected in 33.63% of respiratory infections. In a total of 11 606 cases of viral respiratory infection, 781 were positive for hPIV; hPIV prevalence ranged from 2.14% to 27% of viral respiratory infections. hPIV1 circulates mainly during fall; hPIV3 circulation, in turn, starts in fall and peaks during spring; and cases of hPIV2 are reported along the year, with peaks in fall and early spring. The most affected age group was children, with hPIV prevalence of 74.23% in patients for less than 1 year. A higher proportion of girls were infected than boys, however, no difference by sex was observed considering all age groups. The most frequent type was hPIV3, especially in hospitalized patients. Both hPIV1 and 3 were associated with dyspnea, while hPIV2 caused mild symptoms mainly in nonhospitalized patients. Nineteen fatalities occurred, 89.5% of them associated with risk factors (prematurity; chronic diseases; age, <1 or >60 years).

CONCLUSION

hPIV causes a high number of respiratory infections, leading to hospitalization especially in children; epidemiological and surveillance studies are important for the control and management of respiratory infections.

Sequencing and analysis of globally obtained human parainfluenza viruses 1 and 3 genomes

Human Parainfluenza viruses (HPIV) type 1 and 3 are important causes of respiratory tract infections in young children globally. HPIV infections do not confer complete protective immunity so reinfections occur throughout life. Since no effective vaccine is available for the two virus subtypes, comprehensive understanding of HPIV-1 and HPIV-3 genetic and epidemic features is important for diagnosis, prevention, and treatment of HPIV-1 and HPIV-3 infections. Relatively few whole genome sequences are available for both HPIV-1 and HPIV-3 viruses, so our study sought to provide whole genome sequences from multiple countries to further the understanding of the global diversity of HPIV at a whole-genome level. We collected HPIV-1 and HPIV-3 samples and isolates from Argentina, Australia, France, Mexico, South Africa, Switzerland, and USA from the years 2003-2011 and sequenced the genomes of 40 HPIV-1 and 75 HPIV-3 viruses with Sanger and next-generation sequencing with the Ion Torrent, Illumina, and 454 platforms. Phylogenetic analysis showed that the HPIV-1 genome is evolving at an estimated rate of 4.97 × 10-4 mutations/site/year (95% highest posterior density 4.55 × 10-4 to 5.38 × 10-4) and the HPIV-3 genome is evolving at a similar rate (3.59 × 10-4 mutations/site/year, 95% highest posterior density 3.26 × 10-4 to 3.94 × 10-4). There were multiple genetically distinct lineages of both HPIV-1 and 3 circulating on a global scale. Further surveillance and whole-genome sequencing are greatly needed to better understand the spatial dynamics of these important respiratory viruses in humans.

Small Animal Models of Respiratory Viral Infection Related to Asthma

Respiratory viral infections are strongly associated with asthma exacerbations. Rhinovirus is most frequently-detected pathogen; followed by respiratory syncytial virus; metapneumovirus; parainfluenza virus; enterovirus and coronavirus. In addition; viral infection; in combination with genetics; allergen exposure; microbiome and other pathogens; may play a role in asthma development. In particular; asthma development has been linked to wheezing-associated respiratory viral infections in early life. To understand underlying mechanisms of viral-induced airways disease; investigators have studied respiratory viral infections in small animals. This report reviews animal models of human respiratory viral infection employing mice; rats; guinea pigs; hamsters and ferrets. Investigators have modeled asthma exacerbations by infecting mice with allergic airways disease. Asthma development has been modeled by administration of virus to immature animals. Small animal models of respiratory viral infection will identify cell and molecular targets for the treatment of asthma.

UK circulating strains of human parainfluenza 3: an amplicon based next generation sequencing method and phylogenetic analysis

Background: Human parainfluenza viruses type 3 (HPIV3) are a prominent cause of respiratory infection with a significant impact in both pediatric and transplant patient cohorts.  Currently there is a paucity of whole genome sequence data that would allow for detailed epidemiological and phylogenetic analysis of circulating strains in the UK. Although it is known that HPIV3 peaks annually in the UK, to date there are no whole genome sequences of HPIV3 UK strains available.  Methods: Clinical strains were obtained from HPIV3 positive respiratory patient samples collected between 2011 and 2015.  These were then amplified using an amplicon based method, sequenced on the Illumina platform and assembled using a new robust bioinformatics pipeline. Phylogenetic analysis was carried out in the context of other epidemiological studies and whole genome sequence data currently available with stringent exclusion of significantly culture-adapted strains of HPIV3. Results: In the current paper we have presented twenty full genome sequences of UK circulating strains of HPIV3 and a detailed phylogenetic analysis thereof.  We have analysed the variability along the HPIV3 genome and identified a short hypervariable region in the non-coding segment between the M (matrix) and F (fusion) genes. The epidemiological classifications obtained by using this region and whole genome data were then compared and found to be identical. Conclusions: The majority of HPIV3 strains were observed at different geographical locations and with a wide temporal spread, reflecting the global distribution of HPIV3. Consistent with previous data, a particular subcluster or strain was not identified as specific to the UK, suggesting that a number of genetically diverse strains circulate at any one time. A small hypervariable region in the HPIV3 genome was identified and it was shown that, in the absence of full genome data, this region could be used for epidemiological surveillance of HPIV3.

UK circulating strains of human parainfluenza 3: an amplicon based next generation sequencing method and phylogenetic analysis

Background: Human parainfluenza viruses type 3 (HPIV3) are a prominent cause of respiratory infection with a significant impact in both pediatric and transplant patient cohorts.  Currently there is a paucity of whole genome sequence data that would allow for detailed epidemiological and phylogenetic analysis of circulating strains in the UK. Although it is known that HPIV3 peaks annually in the UK, to date there are no whole genome sequences of HPIV3 UK strains available.  Methods: Clinical strains were obtained from HPIV3 positive respiratory patient samples collected between 2011 and 2015.  These were then amplified using an amplicon based method, sequenced on the Illumina platform and assembled using a new robust bioinformatics pipeline. Phylogenetic analysis was carried out in the context of other epidemiological studies and whole genome sequence data currently available with stringent exclusion of significantly culture-adapted strains of HPIV3. Results: In the current paper we have presented twenty full genome sequences of UK circulating strains of HPIV3 and a detailed phylogenetic analysis thereof.  We have analysed the variability along the HPIV3 genome and identified a short hypervariable region in the non-coding segment between the M (matrix) and F (fusion) genes. The epidemiological classifications obtained by using this region and whole genome data were then compared and found to be identical. Conclusions: The majority of HPIV3 strains were observed at different geographical locations and with a wide temporal spread, reflecting the global distribution of HPIV3. Consistent with previous data, a particular subcluster or strain was not identified as specific to the UK, suggesting that a number of genetically diverse strains circulate at any one time. A small hypervariable region in the HPIV3 genome was identified and it was shown that, in the absence of full genome data, this region could be used for epidemiological surveillance of HPIV3.

New clinical and seasonal evidence of infections by Human Parainfluenzavirus

Human Parainfluenzaviruses (PIVs) account for a significant proportion of viral acute respiratory infections (ARIs) in children, and are also associated with morbidity and mortality in adults, including nosocomial infections. This work aims to describe PIV genotypes and their clinical and epidemiological distribution. Between December 2016 and December 2017, 6121 samples were collected, and submitted to viral culture and genomic quantification, specifically Parainfluenza 1–4 (PIV1–4), Influenza A and B, Respiratory Syncytial Virus (RSV) A and B, Adenovirus, Metapneumovirus, Coronavirus, Rhinovirus, and Enterovirus. Normalized viral load, as (log10) copies/10³ cells, was calculated as virus Ct, determined by multiple qRT-PCR, as a function of the Ct of β-globin. PIV was confirmed in 268 cases (4.37%), and linked to both upper and lower respiratory tract disease, being more frequent in children than in adults (5.23 and 2.43%, respectively). PIV1 and PIV3 were most common (31 and 32.5%, of total PIV positive samples, respectively), with distribution being similar in children and adults, as was viral load. PIV type was correlated with seasonality: PIV3 being more frequent in winter and spring, PIV1 in summer, and PIV 4 in fall. No correlation between vial load and clinical severity was found. Novel findings were that PIV viral load was higher in fall than in other seasons, and PIV4, classically linked to mild respiratory symptoms, was circulating, in children and adults, at all levels of symptoms throughout the year.

Characterization of human parainfluenza virus-3 circulating in Israel, 2012-2015

BACKGROUND

Human parainfluenza virus 3 (hPIV-3) causes respiratory tract infection.

OBJECTIVES

The objective of this study was to describe the epidemiology of hPIV-3 infection among hospitalized patients and characterize the circulating strains.

STUDY DESIGN

A cross-sectional study was conducted using respiratory samples of 15,946 hospitalized patients with respiratory symptoms in 2012-2015 in Israel. All samples were subjected to q-PCR and q-RT-PCR to determine the presence of hPIV-3 and other respiratory viruses. Samples positive for hPIV-3 were subjected to molecular typing and phylogenetic analysis.

RESULTS

Overall, 547 samples 3.4% (95% CI 3.2-3.7) were positive for hPIV-3. Of these 87 (15.9%) were mixed infections; 41.4% with adenovirus, 40.2% with RSV (40.2%) and 19.5% influenza A viruses. The prevalence of hPIV-3 was highest (5.1%) in children aged 0-4 years. Hospitalization in oncology department was associated with increased likelihood of hPIV-3 infection: adjusted odds ratio [aOR] 2.29 (95% confidence intervals [CI] 1.78-2.96), as well as hospitalization in organ transplantation department: aOR 3.65 (95% CI 2.80-4.76). The predominant lineages were C3c (62.3%) and C1b (24.6%), followed by sub-lineages C5 (8.7%) and C3b (2.9%). A new sub-lineage emerged in our analysis, named C1d, which was 17 (1.5%) nucleotide different from C1a, 25 (2.2%) nucleotide different from C1b and 24 (2.1%) nucleotide different from C1c.

DISCUSSION

Young children and immunocompromised patients are likely the risk groups for severe respiratory infections with hPIV-3. Strains belonging to lineages C3c and C1b, which are present worldwide, should be targeted in vaccine development. The emergence of new lineage might have public health implications and on vaccine development.

Human parainfluenza virus infection in severe acute respiratory infection cases in Beijing, 2014-2016: A molecular epidemiological study

Background

Severe acute respiratory infection (SARI) threatens human health and even survival, causing a huge number of hospitalized patients every year. However, as one of the most common respiratory viruses circulated worldwide, the epidemiological and phylogenetic characteristics of human parainfluenza virus (HPIV) in these cases were not well known.

Objectives

To reveal the epidemiological features of HPIV infection in SARIs in Beijing area from September 2014 to August 2016.

Methods

A total of 1229 SARI cases in Beijing area were enrolled, investigated, sampled, and tested by multiplex real‐time PCR to identify HPIVs and other common respiratory viruses. Eighteen HPIV‐3 viruses isolated from all HPIV‐positive samples in these SARI cases were sequenced and analyzed.

Results

Among all enrolled cases, 0.81%, 0.73%, 4.48%, and 0.57% were positive for HPIV‐1 to HPIV‐4, respectively. The highest yield rate of HPIV infection occurred in children under 5 years old (9.07%), followed by the patients over 60 years old (6.02%). The phylogenetic information of HPIV‐3 showed that all viruses belonged to Cluster C3a.

Conclusions

Besides the young children, the elders older than 60 years also showed a relatively high infection rate of HPIVs, which should be given comparable attentions. Moreover, the HPIV‐3 circulating in China undergoes continued evolution, suggesting the potential risk of evolved HPIV infection should not be overlooked.

In vitro sensitivity of human parainfluenza 3 clinical isolates to ribavirin, favipiravir and zanamivir

BACKGROUND

Human parainfluenza type 3 (HPIV3) is an important respiratory pathogen. Although a number of potential therapeutic candidates exist, there is currently no licensed therapy or vaccine. Ribavirin (RBV), favipiravir (FVP) and zanamivir (ZNV) are inhibitors with proven activity against influenza and with potential inhibitory activity against HPIV3 laboratory adapted strains in vitro.

OBJECTIVES

To evaluate RBV, FVP and ZNV as inhibitors of minimally passaged UK clinical strains of HPIV3 as well as a laboratory adapted strain MK9 in vitro.

STUDY DESIGN

The inhibitory action of RBV, FVP and ZNV was evaluated against nine minimally passaged clinical strains and a laboratory adapted strain MK9 using plaque reduction and growth curve inhibition in a cell culture model.

RESULTS

Clinical isolates were found to be at least as susceptible as the laboratory adapted strains to RBV and FVP and significantly more susceptible to ZNV. However the inhibitory concentrations achieved by ZNV against clinical strains remain prohibitively high in vivo.

CONCLUSIONS

RBV, FVP and ZNV were found to be effective inhibitors of HPIV3 in vitro. The lack of efficacy of RBV in vivo may be due to inability to reach required therapeutic levels. FVP, on the other hand, is a good potential therapeutic agent against HPIV3. Further studies using wild type clinical strains, as well as better formulation and delivery mechanisms may improve the utility of these three inhibitors.

Detailed genetic analyses of the HN gene in human respirovirus 3 detected in children with acute respiratory illness in the Iwate Prefecture, Japan

We performed detailed genetic analyses of the partial hemagglutinin-neuraminidase (HN) gene in 34 human respirovirus 3 (HRV3) strains from children with acute respiratory illness during 2013-2015 in Iwate Prefecture, Japan. In addition, we performed analyses of the evolutionary timescale of the gene using the Bayesian Markov chain Monte Carlo (MCMC) method. Furthermore, we analyzed pairwise distances and performed selective pressure analyses followed by linear B-cell epitope mapping and N-glycosylation and phylodynamic analyses. A phylogenetic tree showed that the strains diversified at around 1939, and the rate of molecular evolution was 7.6 × 10^-4 substitutions/site/year. Although the pairwise distances were relatively short (0.03 ± 0.018 [mean ± standard deviation, SD]), two positive selection sites (Cys544Trp and Leu555Ser) and no amino acid substitutions were found in the active/catalytic sites. Six epitopes were estimated in this study, and three mouse monoclonal antibody binding sites (amino acid positions 278, 281, and 461) overlapped with two epitopes belonging to subcluster C3 strains. Bayesian skyline plot analyses indicated that subcluster C3 strains have been increasing from 2004, whereas subcluster C1 strains have declined from 2004. Based on these results, Iwate strains were divided into two subclusters and each subcluster evolved independently. Moreover, our results suggested that some predicted linear epitopes (epitopes 3 and 5) are candidates for an HRV3 vaccine motif. To better understand the details of the molecular evolution of HRV, further studies are needed.

Genetic analysis of human parainfluenza virus type 3 obtained in Croatia, 2011-2015

PURPOSE

This study investigated the HPIV3 circulating strains in Croatia and whether the other parts of HPIV3 genome (F gene and HN 582 nucleotides fragment) could be equally suitable for genetic and phylogenetic analysis.

METHODOLOGY

Clinical materials were collected in period 2011-2015 from children suffering from respiratory illnesses. In positive HPIV3 samples viral genome was partially amplified and sequenced for HN and F genes. Obtained sequences were analysed by phylogenetic analysis and genetic characterization was performed.

RESULTS

All samples from this study belonged to subcluster C and over a short period of time, genetic lineage C3a gained prevalence over the other C genetic lineages, from 39 % in 2011 to more than 90 % in 2013 and 2014. Phylogenetic classifications of HPIV3 based on the entire HN gene, HN 582 nt fragment and entire fusion (F) gene showed identical classification results for Croatian strains and the reference strains. Molecular analysis of the F and HN glycoproteins, showed their similar nucleotide diversity (Fcds P=0.0244 and HNcds P=0.0231) and similar Ka/Ks ratios (F Ka/Ks=0.0553 and HN Ka/Ks=0.0428). Potential N-glycosylation sites, cysteine residues and antigenic sites are generally strongly conserved in HPIV3 glycoproteins from both our and the reference samples.

CONCLUSION

The HPIV3 subclaster C3 (genetic lineage C3a) became the most detected circulating HPIV3 strain in Croatia. The results indicated that the HN 582 nt and the entire F gene sequences were as good for phylogenetic analysis as the entire HN gene sequence.

Genetic analyses of the fusion protein genes in human parainfluenza virus types 1 and 3 among patients with acute respiratory infections in Eastern Japan from 2011 to 2015

PURPOSE

To genetically explore the fusion protein gene (F) in human parainfluenza virus type 1 (HPIV1) and type 3 (HPIV3) strains, we analysed them in patients with acute respiratory infections in Eastern Japan from 2011 to 2015.

METHODOLOGY

We constructed phylogenetic trees based on the HPIV and HPIV3 F gene using the maximum likelihood method and conducted P-distance and selective pressure analyses. We also predicted the linear epitopes of the protein in the prototype strains. Furthermore, we mapped the amino acid substitutions of the proteins.

RESULTS

Nineteen strains of HPIV1 and 53 strains of HPIV3 were detected among the clinical acute respiratory infection cases. The phylogenetic trees indicated that the HPIV1 and HPIV3 strains were classified into clusters II and III and cluster C, respectively. The P-distance values of the HPIV1 and HPIV3 F genes were <0.03. Two positive selection sites were inferred in the HPIV1 (aa 8 and aa 10), and one positive selection site was inferred in the HPIV3 (aa 108), but over 10 negative selection sites were inferred. Four epitopes were predicted for the HPIV1 prototype strains, while five epitopes were predicted for the HPIV3 prototype strain. A positive selection site (aa 108) or the HPIV3 F protein was involved in the predicted epitope. Additionally, we found that an amino acid substitution (R73K) in the LC76627 HPIV3 strain presumably may affect the resistance to neutralization by antibodies.

CONCLUSION

The F gene of HPIV1 and HPIV3 was relatively well conserved in the eastern part of Japan during the investigation period.

Cholesterol reducing agents inhibit assembly of type I parainfluenza viruses

Many enveloped RNA viruses utilize lipid rafts for the assembly of progeny virions, but the role of cholesterol, a major component of rafts, on paramyxovirus budding and virion formation is controversial. In this study, we analyzed the effects of FDA-approved cholesterol-reducing agents, gemfibrozil and lovastatin, on raft formation and assembly of human parainfluenza virus type 1 (hPIV1) and Sendai virus (SeV). Treatment of the human airway epithelial A549 cells with the agents, especially when combined, significantly decreased production of infectious hPIV1 and SeV. Mechanistic analysis indicated that depletion of cellular cholesterol reduced cell surface accumulation of envelope glycoproteins and association of viral matrix and nucleocapsids with raft membrane, which resulted in impaired virus budding and release from the cells. These results indicate that cellular cholesterol is required for assembly and formation of type 1 parainfluenza viruses and suggest that cholesterol could be an attractive target for antiviral agents against hPIV1.

Distribution and Trends of Human Parainfluenza Viruses in Hospitalised Children

OBJECTIVE

To study the distribution of Human Parainfluenza viruses (HPIV) 1-4 and their trends in children ≤5 y of age, hospitalised at a tertiary care centre, Jaipur and co-infection with other respiratory viruses.

METHODS

Nasopharyngeal aspirate and throat swabs were collected and processed for extraction of nucleic acid using automated extraction system and real time RT-PCR was performed using primers and probes specific to HPIV 1-4 and other respiratory viruses on 743 samples.

RESULTS

Total positivity for Parainfluenza viruses 1-4 was found to be 69/743 (9.28 %), of which 50/533 (9.38 %) were boys and 19/210 (9.05 %) girls. Predominance of HPIV- 3 was observed [41/743 (5.52%)] followed by HPIV-1 in 13/743 (1.75%), HPIV-4 in 10/743 (1.34%) and HPIV-2 in 5/743 (0.67%) patients. Maximum positivity was observed in age group 25-36 mo (12.98%) followed by 13-24 mo group (11.96%). HPIVs were found to be circulating round the year and each year. Co-infections with other respiratory viruses were observed in 22/69 (31.88%) of HPIV positive patients.

CONCLUSIONS

All the four types of HPIV were found to be circulating in the index population during all the three years, predominantly during post monsoon and winter seasons. HPIV vaccination should be targeted for all types.

A molecular epidemiological study of human parainfluenza virus type 3 at a tertiary university hospital during 2013-2015 in Catalonia, Spain

Human parainfluenza virus type 3 (HPIV-3) is one of the most common respiratory viruses particularly among young children and immunocompromised patients. The seasonality, prevalence and genetic diversity of HPIV-3 at a Spanish tertiary-hospital from 2013 to 2015 are reported. HPIV-3 infection was laboratory-confirmed in 102 patients (76%, under 5 years of age). Among <5 years-old patients, 9 (11.5%) were under any degree of immunosuppression, whereas this percentage was significantly higher (19; 79.2%) among patients older than 5 years. HPIV-3 was detected at varying levels, but mainly during spring and summer. All characterized HN/F sequences fell within C1b, C5 and in other two closely C3a-related groups. Furthermore, a new genetic lineage (C1c) was described. Genetic similarity and epidemiological data confirmed some nosocomial infections, highlighting the importance of the HPIV-3 surveillance, particularly in high-risk patients. This study provides valuable information on HPIV-3 diversity due to the scarce information in Europe.

•

Children and immunosuppressed adults showed a great susceptibility to infection.

•

Valuable information about the current genetic diversity in Europe is provided.

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Different lineages, including a first described, were locally circulating.

•

Genetic similarity and epidemiological data confirmed some nosocomial infections.

•

The present study highlights the importance of the HPIV-3 surveillance.

Hemagglutinin-neuraminidase gene sequence-based reclassification of human parainfluenza virus 3 variants

The most comprehensive phylogenetic classification of human parainfluenza virus 3 (HPIV-3) was recently developed [PLoS One 2012;7:e43893]. This classification included three distinct clusters (A, B and C) with subdivision of cluster C into four subclusters (C1-4). In the present report, the classification of HPIV-3 was refined by inclusion of 27 overlooked beside newly characterized Saudi variants. The new phylogram was developed and included the same clusters described before, in which cluster A remained unchanged and cluster B contained more recent isolates. The organization of cluster C was altered through inclusion of a new subcluster (C5), subdivision of C1 into two lineages C1a and C1b and subdivision of C3 into three lineages C3a, C3b and C3c. The majority of Saudi variants were classified as members of subcluster C1b, whereas only one variant was placed in each of subclusters C2 and C5. This study illustrates an up-to-date phylogenetic classification of HPIV-3 variants.

Severity of respiratory signs and symptoms and virus profiles in Japanese children with acute respiratory illness

Associations between the severity of respiratory signs and symptoms and the respiratory viruses identified in 214 Japanese children with acute respiratory illness (ARI) enrolled between January and December 2012 were studied. Respiratory rate, wheezing, cyanosis, and the use of accessory muscles were used as indices of respiratory severity and phylogenetic analysis of the viruses identified in these children was performed. Respiratory viruses such as respiratory syncytial virus (RSV), human rhinovirus (HRV), human parainfluenza virus (HPIV), and human metapneumovirus (HMPV) were prevalent, being detected in approximately 70% of the patients (151/214 patients). Co-detection of viruses occurred in about 9% of patients. RSV was identified more frequently in cases scored as moderate/severe than in those scored as mild (P < 0.05). Severity scores of patients with RSV were significantly higher than those of cases with HPIV. Moreover, severity scores in patients with mild disease and co-detections were higher than in those in whom only HPIV or adenovirus was detected. Phylogenetic analysis showed that many genotypes of HRV-A and -C with wide genetic divergence were associated with acute respiratory illness (ARI). On the other hand, only a limited number of genotypes of RSV were associated with ARI. HPIV and HMPV were associated with ARI at similar frequencies. These results suggest that different respiratory viruses with unique genetic characteristics can be found in patients with mild to severe ARI.

Molecular evolution of the haemagglutinin-neuraminidase gene in human parainfluenza virus type 3 isolates from children with acute respiratory illness in Yamagata prefecture, Japan

We conducted detailed genetic analyses of the haemagglutinin-neuraminidase (HN) gene in 272 human parainfluenza virus type 3 (HPIV3) isolates from children with acute respiratory illness during the period 2002-2009 in Yamagata prefecture, Japan. A phylogenetic tree reconstructed by the Bayesian Markov chain Monte Carlo method showed that the strains diversified at around 1946 and that the rate of molecular evolution was 1.10×10(-3) substitutions per site per year. Identity was high among the present strains (<90 %) and the pairwise-distances were short. Furthermore, we found four positive selection sites and some key amino acid substitutions in active/catalytic sites of the HN protein. The results suggest that the HN gene of HPIV3 in the present strains evolved rapidly, similarly to other virus genes such as the G gene of respiratory syncytial virus. However, the biological functions and detailed structures of the HN glycoprotein in some of these strains may have been altered.