Human parainfluenza virus type 2 V protein inhibits and antagonizes tetherin.

Tetherin (BST-2/CD317/HM1.24) is an antiviral membrane protein that prevents the release of enveloped viruses from the cell surface. We found that the growth of human parainfluenza virus type 2 (hPIV-2), but not that of V protein-deficient recombinant hPIV-2, was inhibited by tetherin. V protein immunoprecipitates with tetherin, and this interaction requires its C-terminal Trp residues. The glycosyl phosphatidylinositol attachment signal of tetherin, but not its cytoplasmic tail, was necessary for its binding with V. The distribution of the V protein clearly changed when co-expressed with tetherin in plasmid-transfected cells. hPIV-2 infection of HeLa cells reduced cell surface tetherin without affecting total cellular tetherin. This reduction also occurred in HeLa cells constitutively expressing V, whereas mutated V protein did not affect the cell surface tetherin. Our results suggest that hPIV-2 V protein antagonizes tetherin by binding it and reducing its presence at the cell surface.

Use of laboratory and administrative data to understand the potential impact of human parainfluenza virus 4 on cases of bronchiolitis, croup, and pneumonia in Alberta, Canada.

BACKGROUND: Human Parainfluenza Virus (hPIV) causes severe respiratory illness in infants and adults. Our study describes the association of hPIV1-4 with bronchiolitis, croup, and pneumonia using retrospective laboratory, administrative and public health data. Due to issues including the historic lack of hPIV4 in some commercial respiratory virus panels, the description of the impact of hPIV4 on croup, bronchiolitis, and pneumonia at population levels has often been limited. This study will use routine clinical laboratory data, and administrative data to provide a preliminary description of the impact of hPIV4 on these diseases in our population. METHODS: A three year cohort of patients positive for hPIV was linked with data from physician visits and hospital admissions to define cases and hospitalization status. International Classification of Disease (ICD-9) codes were used to determine if cases had croup, bronchiolitis, and pneumonia. We also looked at differences in hospitalization status, age and gender among hPIV1-4. All statistical analysis was done using SPSS (Version 19.0.0, IBM Corp© 2010) and Graphpad Prism V6 (GraphPad Software, Inc., 2012). RESULTS: Only hPIV1 and hPIV4 specimens had positivity rates greater than 5 % of all specimens sent for respiratory virus panel testing. hPIV1 exhibited a biennial pattern while the pattern for hPIV3 was less interpretable due to lower positivity rates. Circulation patterns for hPIV2 and hPIV4 were not assessed due to the low positivity rates of theses specimens. From 2010 to 2013, there were 2300 hPIV cases with hPIV3 (46 %) being the most common, followed by hPIV1 (27 %), hPIV4 (16 %) and hPIV2 (11 %). The median age was 2 years for all hPIV types. Males were slightly greater than females for hPIV1 and hPIV2, with an equal distribution for hPIV3 and slightly more females than males for hPIV4. hPIV1 and hPIV2 had the highest or proportion of croup while hPIV3 and hPIV4 had the highest proportion of pneumonia. Within hPIV4 cases, distributions of diseases were; pneumonia (21 %, 95 % CI 17.1-25.7), bronchiolitis (18 %, 95 % CI 14.3-22.5), croup (2 %, 95 % CI 0.8-3.9), mixed illness of any of pneumonia, bronchiolitis or croup (4 %, 95 % CI 2.5-7.0) or other respiratory diseases (54 %, 95 % CI 49.1-59.6). CONCLUSIONS: We used laboratory and administrative data to undertake a descriptive analysis of the association of hPIV1-4 with croup, bronchiolitis and pneumonia. hPIV4 appears to be more associated more with bronchiolitis and pneumonia and less with croup in our population.

Clinical and epidemiological characteristics of acute respiratory virus infections in Vietnamese children.

Information about viral acute respiratory infections (ARIs) is essential for prevention, diagnosis and treatment, but it is limited in tropical developing countries. This study described the clinical and epidemiological characteristics of ARIs in children hospitalized in Vietnam. Nasopharyngeal samples were collected from children with ARIs at Ho Chi Minh City Children's Hospital 2 between April 2010 and May 2011 in order to detect respiratory viruses by polymerase chain reaction. Viruses were found in 64% of 1082 patients, with 12% being co-infections. The leading detected viruses were human rhinovirus (HRV; 30%), respiratory syncytial virus (RSV; 23·8%), and human bocavirus (HBoV; 7·2%). HRV was detected all year round, while RSV epidemics occurred mainly in the rainy season. Influenza A (FluA) was found in both seasons. The other viruses were predominant in the dry season. HRV was identified in children of all age groups. RSV, parainfluenza virus (PIV) 1, PIV3 and HBoV, and FluA were detected predominantly in children aged 24 months, respectively. Significant associations were found between PIV1 with croup (P < 0·005) and RSV with bronchiolitis (P < 0·005). HBoV and HRV were associated with hypoxia (P < 0·05) and RSV with retraction (P < 0·05). HRV, RSV, and HBoV were detected most frequently and they may increase the severity of ARIs in children.

Severe parainfluenza virus type 2 supraglottitis in an immunocompetent adult host: an unusual cause of a paramyxoviridae viral infection.

Parainfluenza virus is a major cause of respiratory illness in humans, manifesting from mild upper respiratory tract infection to bronchiolitis and pneumonia, especially in children. We report - to our knowledge - the first case of a nonimmunocompromised adult patient with human parainfluenza type 2 supraglottitis immediately after returning from China.

Acute bronchiolitis and croup.

Croup and acute bronchiolitis are common forms of virally induced respiratory disease in infancy and early childhood. There is good evidence that corticosteroids can ameliorate disease severity and alter the natural history of symptoms in patients who have croup and that temporary symptomatic benefit can be obtained from the use of nebulized adrenaline. The principle weakness when reviewing therapeutic interventions for acute bronchiolitis is the lack of a clear diagnostic test or definition. Current evidence suggests that oxygen is the only useful pharmacologic agent for correcting hypoxia.

Respiratory viruses in laryngeal croup of young children.

OBJECTIVES: To determine the viral cause of laryngeal croup by use of highly sensitive methods, and including recently recognized viruses in the analysis. STUDY DESIGN: One hundred forty-four consecutive children with hoarse voice and inspiratory stridor attending the emergency department were enrolled. Age- and season-matched children presenting with a wheezing illness served as control subjects (n = 76). Nasopharyngeal swabs were analyzed by polymerase chain reaction for rhinovirus and enterovirus, coronavirus, respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza A and B virus, human bocavirus, human metapneumovirus, adenovirus, and Mycoplasma pneumoniae. RESULTS: Virus infection was documented in 80% of patients with croup and 71% of control subjects. Children with croup had significantly more positive test results for PIV 1 and 2 (31% vs 4% and 6% vs 0%, respectively) and significantly fewer positive test results for RSV (15% vs 28%) than wheezing children. Rhinoviruses and enteroviruses were present equally in both groups (21% vs 25%). There was no significant difference in the frequency of influenza A virus or human bocavirus. Few subjects with adenovirus or M. pneumoniae were detected. CONCLUSION: Acute laryngeal croup is most often associated with PIV, RSV, rhinovirus, and enterovirus. Rhinovirus and enterovirus appeared equally often in croup and in wheezing illness. During late fall, they were found in 39% and 40%, respectively, of the tested samples.

Epiglottitis and croup.

Infections of the upper airways are a frequent cause of morbidity in children. Viral laryngotracheobronchitis (croup) is the most common cause of stridor in children and usually has a self-limited course with occasional relapses in early childhood. Epiglottitis has become rare in developed countries with the advent of universal vaccinations against Haemophilus influenzae. It can be rapidly fatal, however, if not promptly recognized and appropriately managed. This article reviews the pathogenesis, epidemiology, clinical presentation, diagnosis, and management of these pediatric upper airway infections.

Clinical and epidemiological characteristics of human parainfluenza virus infections of children in southern Taiwan.

BACKGROUND: Human parainfluenza viruses (HPIV) 1-4 had been analyzed as being one of the most frequent causes of hospitalizations for young children with respiratory tract illnesses. METHODS: This retrospective study was performed from children virologically confirmed as HPIV infection through throat swab or nasopharyngeal aspirates at a tertiary care university hospital, between January 2012 and December 2014. HPIV4 was not checked and analyzed, due to not include in the commercial kit. The demographic, epidemiological, clinical presentations, diagnosis, treatment, outcomes, and laboratory data were analyzed. RESULTS: Totally 398 cases were enrolled, including 39 (9.8%) of HPIV1, 67 (16.8%) of HPIV2, and 292 (73.4%) of HPIV3. The mean age of HPIV-infected children was 2.9 year-old, and 50.5% were among one to three year-old. A total of 56.8% HPIV3-infected children were among one to three years old, however, no HPIV2-infected children was younger than one year-old. The HPIV1-infected patients were more common to develop wheezing and diagnose as acute bronchiolitis. HPIV2-infected children were more likely to have hoarseness (23.9%), and were associated with croup (25.4%). HPIV3 was isolated from two fatal cases, with neurological underlying diseases. CONCLUSION: The impact caused by HPIVs infections is significant in hospitalized children. In the current study, our results contribute to the epidemiologic, clinical and laboratory information of HPIV infection in children in the important areas of respiratory tract infection that could support the development of optimization management.

Human Coronavirus-NL63 infections in Korean children, 2004-2006.

BACKGROUND: Human coronavirus-NL63 (HCoV-NL63) has been isolated from children with respiratory tract infections and its prevalence in Korea has not been reported. OBJECTIVES: This study was designed to investigate the presence and the clinical features of HCoV-NL63 during two winter seasons. STUDY DESIGN: During April 2004-April 2006, nasopharyngeal specimens from children hospitalized with acute respiratory disease were tested for common respiratory viruses, including RSV, influenza A, influenza B, parainfluenza viruses, and adenovirus by IFA. hMPV infection was excluded by nested RT-PCR using primers for F-gene. To detect HCoV-NL63, previously described nested PCR assays for 1a and 1b were used. PCR products of the 1a gene for HCoV-NL63 were sequenced. RESULTS: Out of 872 nasopharyngeal aspirate from children aged under 16 years, 14 (1.7%) were positive for HCoV-NL63. Most of the patients had croup (64.2%) or bronchiolitis (21.4%). The peak prevalence was found in November (28.5%). Most were collected between November 2004 and February 2005. CONCLUSIONS: HCoV-NL63 may be one of the causative agents of acute respiratory tract infection, especially croup.

Oral betamethasone versus intramuscular dexamethasone for the treatment of mild to moderate viral croup: a prospective, randomized trial.

OBJECTIVE: Intramuscular dexamethasone is an effective, but painful, treatment for croup. The effectiveness of betamethasone, an oral, palatable, and equally potent glucocorticoid has not been studied. The purpose of this study was to compare the effectiveness of a single oral dose of betamethasone with intramuscular dexamethasone in the outpatient treatment of mild to moderate croup. METHODS: Children aged 6 months to 6 years presenting to a tertiary care pediatric emergency department (ED) with a modified Westley croup score of 0 to 11 were randomized to receive either 0.6 mg/kg IM dexamethasone or 0.4 mg/kg PO betamethasone. Croup score, heart rate, respiratory rate, pulse oximetry, and need for supplemental treatments were recorded at study entry and at 1, 2, and 4 hours after treatment. Follow-up data were collected by daily telephone follow-up on persistence of symptoms and the need for additional treatment or physician visits up to 7 days after the ED visit. RESULTS: Each study group contained 26 patients. Despite randomization, the mean baseline croup score was higher in the dexamethasone group (3.6 +/- 2.6 vs. 2.0 +/- 2.4, P = 0.03). Patients in both groups showed a significant reduction in the croup score after treatment, and there were no significant differences between croup scores at 4 hours (P = 0.18). Similarly, there were no differences between groups in the hospital admission rate, time to resolution of symptoms, need for additional treatments, or number of return ED visits. CONCLUSION: There is no difference between oral betamethasone and intramuscular dexamethasonein the management of mild to moderate viral croup. It is palatable and does not require a nurse for administration, making it a good alternative for ambulatory management.

Croup is associated with the novel coronavirus NL63.

BACKGROUND: The clinical relevance of infections with the novel human coronavirus NL63 (HCoV-NL63) has not been investigated systematically. We therefore determined its association with disease in young children with lower respiratory tract infection (LRTI). METHODS AND FINDINGS: Nine hundred forty-nine samples of nasopharyngeal secretions from children under 3 y of age with LRTIs were analysed by a quantitative HCoV-NL63-specific real-time PCR. The samples had been collected from hospitalised patients and outpatients from December 1999 to October 2001 in four different regions in Germany as part of the prospective population-based PRI.DE study and analysed for RNA from respiratory viruses. Forty-nine samples (5.2%), mainly derived from the winter season, were positive for HCoV-NL63 RNA. The viral RNA was more prevalent in samples from outpatients (7.9%) than from hospitalised patients (3.2%, p = 0.003), and co-infection with either respiratory syncytial virus or parainfluenza virus 3 was observed frequently. Samples in which only HCoV-NL63 RNA could be detected had a significantly higher viral load than samples containing additional respiratory viruses (median 2.1 x 10(6) versus 2.7 x 10(2) copies/ml, p = 0.0006). A strong association with croup was apparent: 43% of the HCoV-NL63-positive patients with high HCoV-NL63 load and absence of co-infection suffered from croup, compared to 6% in the HCoV-NL63-negative group, p < 0.0001. A significantly higher fraction (17.4%) of samples from croup patients than from non-croup patients (4.2%) contained HCoV-NL63 RNA. CONCLUSION: HCoV-NL63 infections occur frequently in young children with LRTI and show a strong association with croup, suggesting a causal relationship.

Use of dexamethasone in the outpatient management of acute laryngotracheitis.

OBJECTIVE: Recent studies have demonstrated that a single intramuscular injection of dexamethasone (0.6 mg/kg) shortens the duration and severity of illness in hospitalized patients with acute viral laryngotracheitis (croup). Our objective was to determine if dexamethasone has a role in the outpatient management of patients with acute viral croup of moderate severity. METHODS: Patients, 6 months to 5 years of age, who came to the emergency department (ED) with acute viral croup, a croup score of at least 2 (range 0 to 17), and a disposition of discharge were randomized in a double-blind fashion to receive a single intramuscular injection of dexamethasone, 0.6 mg/kg, or an equal volume of normal saline before discharge from the ED. Patients were excluded if they had any structural abnormalities, had received any steroids in the preceding 24 hours, or if they required beta-agonist therapy, more than one racemic epinephrine treatment, or hospitalization. Patients were followed up by telephone 24 hours and 7 to 10 days after discharge to determine whether additional medical attention was sought for perceived lack of improvement or worsening of symptoms. Secondary outcome included the parents' perception of how the child was doing at 24 hours, based on a 4-point ordinal scale: worse (1), same (2), improved (3), symptoms resolved (4), and the number of days it took for complete recovery. RESULTS: Of the 38 patients comprising the study group, 19 received dexamethasone. The median age was 19 months (range 6 to 66 months), and median pretreatment croup score was 3 (range 2 to 5) for both groups. The number of patients requiring racemic epinephrine was similar in both groups. Five patients sought additional medical attention within 48 hours. Four of the five patients had received placebo (21% of the placebo group) and one had received dexamethasone (5% of the steroid group) (not statistically significant). At the 24-hour telephone follow-up, significantly more patients in the dexamethasone group had a score consistent with improvement compared with placebo (84% vs 42%, P = .003). There was no difference in the number of days for symptoms to completely resolve between the two groups. CONCLUSION: The use of dexamethasone in the outpatient management of viral croup was associated with a reduction in severity of illness within 24 hours after treatment. Patients with viral croup of moderate severity should be considered as candidates for the use of dexamethasone before discharge from the ED.

Nebulized budesonide is as effective as nebulized adrenaline in moderately severe croup.

OBJECTIVE: Nebulized budesonide and nebulized adrenaline have been shown to be effective in the treatment of moderately severe croup. However, there has been no direct comparison of these therapies. We undertook a multicenter, randomized, double-blind, parallel group study in 66 hospitalized children with viral or spasmodic croup. METHODS: Children 0.5 to 6 years of age were assessed using a validated croup symptom score (stridor, 0 through 4; cough, 0 through 3; retractions, 0 through 3; dyspnea, 0 through 3; and color, 0 through 4) at 0.5, 1, 1.5, 2, 12, and 24 hours after nebulization. Patients received either budesonide (2 mg/4 mL) or L-adrenaline (4 mg/4 mL) via nebulization. The primary outcome measure was change in the total croup symptom score. RESULTS: Thirty-five children received budesonide and 31 received adrenaline. There was no significant difference in baseline features, including croup score (mean [95% confidence interval]: budesonide, 7.1 [6.7-7.5]; adrenaline, 7.7 [7.3-8.1]). All patients had significant improvement from baseline, and there was not significant difference between the two treatments, as measured by change in croup scores, change in oxygen saturation, duration of hospitalization, number of subsequent treatments with systemic steroids or adrenaline, and adverse events. No child required intubation. CONCLUSION: This study does not show any difference in efficacy and safety between nebulized budesonide and nebulized adrenaline in the treatment of acute upper airway obstruction in patients with moderately severe croup.

Viral croup: current diagnosis and treatment.

Viral croup, a common illness in children, manifests with noisy, labored breathing. Parainfluenza viruses are the most common cause of croup; however, other causes including epiglottitis and bacterial tracheitis should be considered in the differential diagnosis. The diagnosis is primarily based on clinical findings; imaging studies may be useful in selected cases. Although most children recover from this self-limited illness with only minimal medical intervention, some are severely affected by laryngeal swelling and require respiratory support with analgesics, cool mist, corticosteroids, nebulized epinephrine, heliox, and, rarely, intubation. In this article, the current diagnostic and management strategies for viral croup are summarized.

Clinical courses of croup caused by influenza and parainfluenza viruses.

Influenza viruses have occasionally been associated with severe manifestations of croup, but no comparative studies of different viral etiologies are available. In a retrospective study we compared the clinical courses of croup caused by influenza and parainfluenza viruses in hospitalized children. By several indicators the clinical picture of croup caused by influenza viruses was significantly more severe than that caused by parainfluenza viruses.

A multiplex RT-PCR for the detection of parainfluenza viruses 1-3 in clinical samples.

Parainfluenza viruses (PIV) are an important cause of respiratory morbidity. Conventional diagnostic methods for detection of PIV are time consuming or lack sensitivity. A multiplex PCR that detects PIV 1-3 was developed using novel primers for PIV viruses 1 and 2 and primers for PIV 3 described previously. Following RNA extraction a single multiplex reverse transcription was undertaken using antisense primers specific for each virus type. This was followed by a 40-cycle multiplex PCR using primers directed towards the haemagglutinin-neuraminidase coding region of each virus type. Products were probed with type-specific fluorescein labelled internal probes and detected by chemiluminescence. Cultured PIV viruses were detectable to a sensitivity of 1 TCID50. The technique was applied to 57 nasal aspirates taken from children presenting with various acute respiratory conditions and analysed previously by culture, immunofluorescence and/or serology. It was possible to detect PIV 1, 2 or 3 in 13/13 samples found previously positive for PIV by tissue culture, 13/15 found previously positive by immunofluorescence and 6/10 that coincided with positive serology. None of the samples found previously positive for other viruses (26) or negative to virus detection (6) were found positive by RT-PCR. It is concluded that this method is as sensitive as combined immunofluorescence and tissue culture for the detection of the PIV viruses 1-3 and should be useful for rapid diagnosis of PIV 1-3 infections.

Clinical manifestations of parainfluenza infection in children.

Parainfluenza viruses are major pathogens causing respiratory illness, manifesting from mild upper respiratory tract infection to bronchiolitis and pneumonia. This retrospective study aimed at providing clinical and epidemiologic data addressing the parainfluenza virus infection in Taiwan. A total of 39 patients were enrolled in this study from March 1999 to December 2000. Infants and young children were the major susceptible population, with 87.2% of them younger than 3 years. No seasonal trend was noted for parainfluenza type 1 and type 2 infections. One clustering of parainfluenza virus type 3 infections occurred in late spring of 2000 based on collected results. Parainfluenza type 1 viral isolates accounted for all of the cases of croup. Most isolates of parainfluenza virus type 3 were associated with upper and/or lower respiratory tract infections. A substantial proportion of the patients had skin involvement; the identification of one case of possible parainfluenza virus-related erythema multiforme is particularly interesting, especially because the chances of a causal relation between viral infection and skin symptoms are formerly thought to be slight. The identification of parainfluenza virus in illnesses classically considered to be due to other viruses is intriguing and may have important implications in the management of childhood illness clinically.

Viral croup: a current perspective.

Viral croup is the most common cause of upper airway obstruction in children 6 months to 6 years of age. Parainfluenza virus accounts for the majority of cases. The disease is characterized by varying degrees of inspiratory stridor, barking cough, and hoarseness because of laryngeal and/or tracheal obstruction. The diagnosis is mainly a clinical one and diagnostic studies usually are not necessary. The management has altered dramatically in the past decade. Good evidence exists to support the routine use of corticosteroid in all children with croup. Intervention at an earlier phase of the illness will reduce the severity of the symptoms and the rates of return to a health care practitioner for additional medical attention, visits to the emergency department, and admission to the hospital. Most children respond to a single, oral dose of dexamethasone. For those who do not tolerate the oral preparation, nebulized budesonide or intramuscular dexamethasone are reasonable alternatives. Nebulized epinephrine should be reserved for patients with moderate to severe croup. Simultaneous administration of corticosteroid and epinephrine reduces the rate of intubation in patients with severe croup and impending respiratory failure.

Common (but not always considered) viral infections of the lower respiratory tract.

Viral lower respiratory tract infections continue to cause a great deal of morbidity and mortality in the United States and worldwide, despite advances in treatment options, chemoprophylaxis, and vaccine development. The availability of ribavirin has improved the outlook in high-risk patients who develop respiratory syncytial virus bronchiolitis while intensive efforts are continued to develop an efficacious and safe vaccine. Respiratory syncytial virus immunoglobulin may prove to be a useful tool in the armamentarium of the pediatrician to prevent or modify respiratory syncytial virus disease in individual patients. Influenza vaccination and chemoprophylaxis remain mainstays in the prevention of influenza disease in high-risk individuals. The availability of a vaccine for varicella and a wider dissemination of measles vaccine, particularly in developing nations, may well limit the adverse outcomes associated with pneumonias caused by these two viruses. The transplant patient and other immunocompromised patients will continue to challenge clinicians and scientists to provide innovative and effective therapies for viral infections. The exciting advances in clinical and research virology over the last decade offer much hope to practicing pediatricians who struggle with offering prevention strategies and treatment options for their patients. Viral lower respiratory tract infections will never be eliminated as a clinical problem, although the morbidity and mortality associated with them will continue to improve.