Respiratory viruses and exacerbations of asthma in adults.

OBJECTIVE--To study the role of respiratory viruses in exacerbations of asthma in adults. DESIGN--Longitudinal study of 138 adults with asthma. SETTING--Leicestershire Health Authority. SUBJECTS--48 men and 90 women 19-46 years of age with a mean duration of wheeze of 19.6 years. 75% received regular treatment with bronchodilators; 89% gave a history of eczema, hay fever, allergic rhinitis, nasal polyps, or allergies; 38% had been admitted to hospital with asthma. MAIN OUTCOME MEASURES--Symptomatic colds and asthma exacerbations; objective exacerbations of asthma with > or = 50 l/min reduction in mean peak expiratory flow rate when morning and night time readings on days 1-7 after onset of symptoms were compared with rates during an asymptomatic control period; laboratory confirmed respiratory tract infections. RESULTS--Colds were reported in 80% (223/280) of episodes with symptoms of wheeze, chest tightness, or breathlessness, and 89% (223/250) of colds were associated with asthma symptoms. 24% of 115 laboratory confirmed non-bacterial infections were associated with reductions in mean peak expiratory flow rate > or = 50 l/min through days 1-7 and 48% had mean decreases > or = 25 l/min. 44% of episodes with mean decreases in flow rate > or = 50 l/min were associated with laboratory confirmed infections. Infections with rhinoviruses, coronaviruses OC43 and 229E, influenza B, respiratory syncytial virus, parainfluenza virus, and chlamydia were all associated with objective evidence of an exacerbation of asthma. CONCLUSIONS--These findings show that asthma symptoms and reductions in peak flow are often associated with colds and respiratory viruses; respiratory virus infections commonly cause or are associated with exacerbations of asthma in adults.     

Long-Term Shedding of Influenza Virus,Parainfluenza Virus,Respiratory Syncytial Virus and Nosocomial Epidemiology in Patients with Hematological Disorders

Respiratory viruses are a cause of upper respiratory tract infections (URTI), but can be associated with severe lower respiratory tract infections (LRTI) in immunocompromised patients. The objective of this study was to investigate the genetic variability of influenza virus, parainfluenza virus and respiratory syncytial virus (RSV) and the duration of viral shedding in hematological patients. Nasopharyngeal swabs from hematological patients were screened for influenza, parainfluenza and RSV on admission as well as on development of respiratory symptoms. Consecutive swabs were collected until viral clearance. Out of 672 tested patients, a total of 111 patients (17%) were infected with one of the investigated viral agents: 40 with influenza, 13 with parainfluenza and 64 with RSV; six patients had influenza/RSV or parainfluenza/RSV co-infections. The majority of infected patients (n = 75/111) underwent stem cell transplantation (42 autologous, 48 allogeneic, 15 autologous and allogeneic). LRTI was observed in 48 patients, of whom 15 patients developed severe LRTI, and 13 patients with respiratory tract infection died. Phylogenetic analysis revealed a variety of influenza A(H1N1)pdm09, A(H3N2), influenza B, parainfluenza 3 and RSV A, B viruses. RSV A was detected in 54 patients, RSV B in ten patients. The newly emerging RSV A genotype ON1 predominated in the study cohort and was found in 48 (75%) of 64 RSV-infected patients. Furthermore, two distinct clusters were detected for RSV A genotype ON1, identical RSV G gene sequences in these patients are consistent with nosocomial transmission. Long-term viral shedding for more than 30 days was significantly associated with prior allogeneic transplantation (p = 0.01) and was most pronounced in patients with RSV infection (n = 16) with a median duration of viral shedding for 80 days (range 35–334 days). Long-term shedding of respiratory viruses might be a catalyzer of nosocomial transmission and must be considered for efficient infection control in immunocompromised patients.     

Significance of Legionella pneumophila in human respiratory pathology

The etiological structure of acute pneumonia and acute respiratory diseases was studied with a view to establishing the proportion of L. pneumophila among other causative agents of such diseases. A total of 299 patients were examined over time. The etiological diagnosis based on the data of serological examination was made in 70.6% of the patients with acute pneumonia and in 65% of the patients with acute respiratory viral infections and influenza. In the etiology of pneumonia, the leading role was found to belong to influenza A (H3N2) and B viruses, as well as to adenovirus, while in the etiology of acute respiratory viral infections and influenza, to influenza B virus, adenovirus and Mycoplasma pneumoniae. The importance of L. pneumophila in the etiology of acute pneumonia and acute respiratory diseases was shown. The proportion of L. pneumophila proved to be, on the average, 9.9% in acute pneumonia and 9.8% in acute respiratory diseases. L. pneumophila occurred most frequently in mixed infections in combination with adenovirus and influenza B virus. Diseases of Legionella etiology were found to have a seasonal character, occurring mostly in winter and spring.     

Elevated viral antibody titres in spontaneous abortion

Abstract To assess the possible role of virus infections in spontaneous abortion we undertook a prospective study of three groups of patients: women who had a spontaneous abortion; women seen in the ante-natal booking clinic; and those undergoing therapeutic termination of pregnancy. Venous blood was taken for antibody detection, cervical swabs for virus isolation, and in the cases of spontaneous and therapeutic abortion products of conception were sent for virus culture. The infectious agents studied were influenza A and B, adenovirus, respiratory syncytial virus, measles, psittacosis, Varicella zoster , and mumps virus. Statistical analysis revealed that women in the spontaneous abortion group has a higher incidence of antibodies against respiratory syncytial virus ( P <0.01), and mumps virus ( P <0.01). Among women seropositive for each virus, higher titres were found only for respiratory syncytial virus ( P <0.05) in cases rather than controls. These results could be explained if viruses such as respiratory syncytial virus caused abortion or if women having a spontaneous abortion mount exaggerated immune responses to fetal adn viral infections, and the former altered immune response is associated with spontaneous abortion.     

Elevated viral antibody titres in spontaneous abortion

To assess the possible role of virus infections in spontaneous abortion we undertook a prospective study of three groups of patients: women who had a spontaneous abortion; women seen in the antenatal booking clinic; and those undergoing therapeutic termination of pregnancy. Venous blood was taken for antibody detection, cervical swabs for virus isolation, and in the cases of spontaneous and therapeutic abortion products of conception were sent for virus culture. The infectious agents studied were influenza A and B, adenovirus, respiratory syncytial virus, measles, psittacosis, Varicella zoster, and mumps virus. Statistical analysis revealed that women in the spontaneous abortion group has a higher incidence of antibodies against respiratory syncytial virus (P less than 0.01), and mumps virus (P less than 0.01). Among women seropositive for each virus, higher titres were found only for respiratory syncytial virus (P less than 0.05) in cases rather than controls. These results could be explained if viruses such as respiratory syncytial virus caused abortion or if women having a spontaneous abortion mount exaggerated immune responses to fetal and viral infections, and the former altered immune response is associated with spontaneous abortion.     

Aetiology of upper respiratory tract infections in children in Arak city: a community based study

Viruses are frequent causes of upper respiratory tract infections in children. We investigated the viral aetiology of community-acquired upper respiratory tract infections (URIs) in young children treated as outpatients in community settings. During November 2008, nasal swab specimens were taken from children with recent onset of upper respiratory tract infections. The patients attended day care or primary schools; the specimens were randomly obtained by pediatricians from schools and childcare institutions and sent for identification by PCR method. A total of 300 specimens were collected. From all samples, 40.67% were positive for at least 1 virus, viz. adenovirus 11.76%, rhinovirus 9.8%, respiratory syncytial virus 6.08%, influenza virus 5.56%, parainfluenza virus 4.9%, enterovirus 2.94% and a combination of 2 viruses 2%. Clinical manifestations of the respiratory infections were as follows: 70.7% of the patients had coryza, 69.3% cough, 26% sneezing, 19.7% sore throat, 2.7% headache, 7.7% fever, 2.3% conjunctivitis, 1.3% abdominal pain and 1% hoarseness. The results of this study demonstrate that adenoviruses and rhinoviruses are the two most common viral agents isolated from pediatric outpatients with acute URIs in autumn in Arak City. Coryza and cough were the most common symptoms in children. Sore throat and hoarseness were more prevalent in infections caused by influenza virus, conjunctivitis in parainfluenza, and coryza in rhinovirus infections.     

Acute viral infections of upper respiratory tract in elderly people living in the community: comparative,prospective, population based study of disease burden.

OBJECTIVE: To evaluate the disease burden of upper respiratory infections in elderly people living at home. DESIGN: Prospective surveillance of elderly people. INTERVENTION: None. SETTING: Leicestershire, England SUBJECTS: 533 subjects 60 to 90 years of age. MAIN OUTCOME MEASURES: Pathogens, symptoms, restriction of activity, duration of illness, medical consultations, interval between onset of illness and medical consultation, antibiotic use, admission to hospital, and death. RESULTS: 231 pathogens were identified for 211 (43%) of 497 episodes for which diagnostic specimens were available: 121 (52%) were rhinoviruses, 59 (26%) were coronaviruses, 22 (9.5%) were influenza A or B, 17 (7%) were respiratory syncytial virus, 7 (3%) were parainfluenza viruses, and 3 (1%) were Chlamydia species; an adenovirus and Mycoplasma pneumoniae caused one infection each. Infections occurred at a rate of 1.2 episodes per person per annum (95% confidence interval 1.0 to 1.7; range 0-10) and were clinically indistinguishable. Lower respiratory tract symptoms complicated 65% of upper respiratory infections and increased the medical consultation rate 2.4-fold (chi 2 test P < 0.001). The median interval between onset of illness and medical consultation was 3 days for influenza and 5 days for other infections. Rhinoviruses caused the greatest disease burden overall followed by episodes of unknown aetiology, coronaviruses, influenza A and B, and respiratory syncytial virus. CONCLUSIONS: Respiratory viruses cause substantial morbidity in elderly people. Although respiratory syncytial virus and influenza cause considerable individual morbidity, the burden of disease from rhinovirus infections and infections of unknown aetiology seems greater overall. The interval between onset of illness and consultation together with diagnostic difficulties raises concern regarding the role of antiviral drugs in treating influenza.     

Respiratory viruses in the pediatric intensive care unit: prevalence and clinical aspects

A survey was conducted in two pediatric intensive care units in hospitals in Porto Alegre, Brazil, in order to monitor the main respiratory viruses present in bronchiolitis and/or pneumonia and their involvement in the severity of viral respiratory infections. Viral respiratory infection prevalence was 38.7%. In bronchiolitis, respiratory syncytial virus (RSV) was detected in 36% of the cases. In pneumonia, the prevalence rates were similar for adenovirus (10.3%) and RSV (7.7%). There was a difference among the viruses detected in terms of frequency of clinical findings indicating greater severity. Frequency of crackles in patients with RSV (47.3%) showed a borderline significance (p = 0.055, Fisher's exact test) as compared to those with adenovirus (87.5%). The overall case fatality rate in this study was 2.7%, and adenovirus showed a significantly higher case fatality rate (25%) than RSV (2.8%) (p = 0.005). Injected antibiotics were used in 49% of the children with RSV and 60% of those with adenovirus. Adenovirus was not detected in any of the 33 children submitted to oxygen therapy.     

Respiratory viruses and sudden infant death.

Viruses were shown to be present in the respiratory tract in 200 of 763 cases of the sudden infant death syndrome studied in the nine years 1974-82. Epidemiological and pathological evidence suggested that the distribution of viruses in the sudden infant death syndrome differs between infants aged 3 months or less and those aged over 3 months: the incidence of detection of virus was 14% in the younger group compared with 39% in the older group. The distribution of the viruses in these two groups was compared with that in 1341 live infants with respiratory virus infections. Adenovirus, influenza virus, parainfluenza virus, and rhinovirus had similar distribution among the victims of the sudden infant death syndrome and live controls. The incidence of detection of respiratory syncytial virus was increased in the older infants dying of the sudden infant death syndrome (90% of the cases detected) compared with the older group of live infants (53%). Antibody studies, detection of virus, and epidemiological data suggest that respiratory syncytial virus may be a precipitating factor of sudden death in older infants.     

Respiratory viruses augment the adhesion of bacterial pathogens to respiratory epithelium in a viral species- and cell type-dependent manner

Secondary bacterial infections often complicate respiratory viral infections, but the mechanisms whereby viruses predispose to bacterial disease are not completely understood. We determined the effects of infection with respiratory syncytial virus (RSV), human parainfluenza virus 3 (HPIV-3), and influenza virus on the abilities of nontypeable Haemophilus influenzae and Streptococcus pneumoniae to adhere to respiratory epithelial cells and how these viruses alter the expression of known receptors for these bacteria. All viruses enhanced bacterial adhesion to primary and immortalized cell lines. RSV and HPIV-3 infection increased the expression of several known receptors for pathogenic bacteria by primary bronchial epithelial cells and A549 cells but not by primary small airway epithelial cells. Influenza virus infection did not alter receptor expression. Paramyxoviruses augmented bacterial adherence to primary bronchial epithelial cells and immortalized cell lines by up-regulating eukaryotic cell receptors for these pathogens, whereas this mechanism was less significant in primary small airway epithelial cells and in influenza virus infections. Respiratory viruses promote bacterial adhesion to respiratory epithelial cells, a process that may increase bacterial colonization and contribute to disease. These studies highlight the distinct responses of different cell types to viral infection and the need to consider this variation when interpreting studies of the interactions between respiratory cells and viral pathogens.     

Detection of human bocavirus and human metapneumovirus by real-time PCR from patients with respiratory symptoms in Southern Brazil

The introduction of newer molecular methods has led to the discovery of new respiratory viruses, such as human metapneumovirus (hMPV) and human bocavirus (hBoV), in respiratory tract specimens. We have studied the occurrence of hMPV and hBoV in the Porto Alegre (PA) metropolitan area, one of the southernmost cities of Brazil, evaluating children with suspected lower respiratory tract infection from May 2007-June 2008. A real-time polymerase chain reaction method was used for amplification and detection of hMPV and hBoV and to evaluate coinfections with respiratory syncytial virus (RSV), influenza A and B, parainfluenza 1, 2 and 3, human rhinovirus and human adenovirus. Of the 455 nasopharyngeal aspirates tested, hMPV was detected in 14.5% of samples and hBoV in 13.2%. A unique causative viral agent was identified in 46.2% samples and the coinfection rate was 43.7%. For hBoV, 98.3% of all positive samples were from patients with mixed infections. Similarly, 84.8% of all hMPV-positive results were also observed in mixed infections. Both hBoV and hMPV usually appeared with RSV. In summary, this is the first confirmation that hMPV and hBoV circulate in PA; this provides evidence of frequent involvement of both viruses in children with clinical signs of acute viral respiratory tract infection, although they mainly appeared as coinfection agents.     

High Incidence of Multiple Viral Infections Identified in Upper Respiratory Tract Infected Children under Three Years of Age in Shanghai, China

Background

Upper respiratory tract infection (URTI) is a major reason for hospitalization in childhood. More than 80% of URTIs are viral. Etiological diagnosis of URTIs is important to make correct clinical decisions on treatment methods. However, data for viral spectrum of URTIs are very limited in Shanghai children.

Methods

Nasopharyngeal swabs were collected from a group of 164 children aged below 3 years who were hospitalized due to acute respiratory infection from May 2009 to July 2010 in Shanghai. A VRDAL multiplex PCR for 10 common respiratory viruses was performed on collected specimens compared with the Seeplex® RV15 ACE Detection kit for 15 respiratory viruses.

Results

Viruses were detected in 84 (51.2%) patients by VRDAL multiplex PCR, and 8 (4.9%) of cases were mixed infections. Using the Seeplex® RV15 ACE Detection kit, viruses were detected in 129 (78.7%) patients, 49 (29.9%) were co-infected cases. Identified viruses included 37 of human rhinovirus (22.6% of cases), 32 of influenza A virus (19.5%), 30 of parainfluenzavirus-2 (18.3%), 23 of parainfluenzavirus-3 (14.0%), 15 of human enterovirus (9.1%), 14 each of parainfluenzavirus-1, respiratory syncytial virus B and adenovirus (8.5%), 8 of coronavirus 229E/NL63 (4.9%), 6 of human bocavirus (3.7%), 5 each of influenza B virus and respiratory syncytial virus A (3.0%), 3 of parainfluenzavirus-4 (1.8%), 2 of coronavirus OC43/HKU1 (1.2%), and 1 human metapneumovirus (0.6%).

Conclusions

A high frequency of respiratory infections (78.7%) and co-infections (29.9%) was detected in children with acute respiratory infection symptoms in Shanghai. The Seeplex® RV15 ACE detection method was found to be a more reliable high throughput tool than VRDAL method to simultaneously detect multiple respiratory viruses.     

280例呼吸道感染儿童呼吸道病毒病原学检出情况及流行规律分析

目的:了解呼吸道感染儿童呼吸道病毒病原学检出情况及其流行规律,为儿童呼吸道感染的预防、诊断及治疗提供病原学依据。方法:选取2016年1月-2017年12月期间中国人民解放军中部战区总医院收治的280例呼吸道感染患儿为研究对象,分析患儿呼吸道分泌物中呼吸道病毒的检出情况,并分析呼吸道感染儿童呼吸道病毒感染与年龄、季节、疾病类型的关系。结果:280例呼吸道感染患儿中共检出98份阳性标本,阳性率为35.00%,其中有2份标本中检出2种病毒感染,混合感染阳性率为0.71%;在所有病毒类型中,呼吸道合胞病毒(RSV)病毒感染阳性率最高。1岁患儿的病毒感染阳性率最高,与其他年龄段病毒感染阳性率比较差异有统计学意义(P0.05)。呼吸道感染患儿春季、冬季的病毒感染阳性率明显高于夏季、秋季(P0.05)。不同呼吸道感染疾病类型患儿病毒感染阳性率比较差异有统计学意义(P0.05),以喘息性肺炎、毛细支气管炎、肺炎患儿病毒感染阳性率较高。结论:RSV是呼吸道感染儿童呼吸道病毒感染的主要致病病原体,1岁的婴幼儿较易感染,春季、冬季为其高发季节,且以肺炎、毛细支气管炎、喘息性肺炎患儿的病毒感染阳性率较高。     

Respiratory Viruses Associated Hospitalization among Children Aged <5 Years in Bangladesh: 2010-2014

Background

We combined hospital-based surveillance and health utilization survey data to estimate the incidence of respiratory viral infections associated hospitalization among children aged < 5 years in Bangladesh.

Methods

Surveillance physicians collected respiratory specimens from children aged <5 years hospitalized with respiratory illness and residing in the primary hospital catchment areas. We tested respiratory specimens for respiratory syncytial virus, parainfluenza viruses, human metapneumovirus, influenza, adenovirus and rhinoviruses using rRT-PCR. During 2013, we conducted a health utilization survey in the primary catchment areas of the hospitals to determine the proportion of all hospitalizations for respiratory illness among children aged <5 years at the surveillance hospitals during the preceding 12 months. We estimated the respiratory virus-specific incidence of hospitalization by dividing the estimated number of hospitalized children with a laboratory confirmed infection with a respiratory virus by the population aged <5 years of the catchment areas and adjusted for the proportion of children who were hospitalized at the surveillance hospitals.

Results

We estimated that the annual incidence per 1000 children (95% CI) of all cause associated respiratory hospitalization was 11.5 (10–12). The incidences per 1000 children (95% CI) per year for respiratory syncytial virus, parainfluenza, adenovirus, human metapneumovirus and influenza infections were 3(2–3), 0.5(0.4–0.8), 0.4 (0.3–0.6), 0.4 (0.3–0.6), and 0.4 (0.3–0.6) respectively. The incidences per 1000 children (95%CI) of rhinovirus-associated infections among hospitalized children were 5 (3–7), 2 (1–3), 1 (0.6–2), and 3 (2–4) in 2010, 2011, 2012 and 2013, respectively.

Conclusion

Our data suggest that respiratory viruses are associated with a substantial burden of hospitalization in children aged <5 years in Bangladesh.     

Rapid detection and clinical features of infants and young children with acute lower respiratory tract infection due to respiratory syncytial virus

During December to the end of February of 2003 and 2004, a total of 282 nasopharyngeal aspirates were obtained from infants and young children admitted to the Buraidah Maternity and Pediatric Hospital, Al-Qassim, Saudi Arabia, and clinically diagnosed as suffering from acute lower respiratory tract infections. The aspirates were tested for the presence of respiratory syncytial virus using direct fluorescein-labeled monoclonal antibody assay. Of the 282 specimens, 128 (45.4%) were found to be positive for respiratory syncytial virus. The most positive specimens came from patients less than one year old (51.3%), and were associated with bronchopneumonia (56.7%) or bronchiolits (55.4%). Coughing (100%) and tachpnea (98%) were significantly more frequent in infants with respiratory syncytial virus infection, followed by wheezing, crepitation and retraction, each representing 66%. Three deaths were reported. The availability of a rapid viral diagnostic assay will be an important tool for physicians to make more accurate treatment decisions and therefore reduce unnecessary antibiotic usage and hospital stay for the patients.     

Studies on the epidemiology of child infections. 3. Parainfluenza viruses (types 1-4) and respiratory syncytial virus infections.

A seroepidemiological study on the rate of neutralizing antibodies for parainfluenza viruses (types 1-4) and for the respiratory syncytial virus in 2,514 infants and children between 0 and 15 years, residing in Bari and its hinterland was carried out. Positive results were very high for both the individual parainfluenza serotypes (81.7% for type 3, 78.0% for type 1, 76.6% for type 4, 71.9% for type 2) and for respiratory syncytial virus (88.5%). The pattern of infections due to respiratory syncytial virus differed from that of the parainfluenza viruses not only for the higher serologic positive rate, but also for the larger number of elevated titre responses in each age group.     

Viral Etiology and Clinical Profiles of Children with Severe Acute Respiratory Infections in China

Background

No comprehensive analysis is available on the viral etiology and clinical characterization among children with severe acute respiratory infection (SARI) in China during 2009 H1N1 pandemic and post-pandemic period.

Methods

Cohort of 370 hospitalized children (1 to 72 months) with SARI from May 2008 to March 2010 was enrolled in this study. Nasopharyngeal aspirate (NPA) specimens were tested by a commercial assay for 18 respiratory viral targets. The viral distribution and its association with clinical character were statistically analyzed.

Results

Viral pathogen was detected in 350 (94.29%) of children with SARI. Overall, the most popular viruses were: enterovirus/rhinovirus (EV/RV) (54.05%), respiratory syncytial virus (RSV) (51.08%), human bocavirus (BoCA) (33.78%), human parainfluenzaviruse type 3 (PIV3) (15.41%), and adenovirus (ADV) (12.97%). Pandemic H1N1 was the dominant influenza virus (IFV) but was only detected in 20 (5.41%) of children. Moreover, detection rate of RSV and human metapneumovirus (hMPV) among suburb participants were significantly higher than that of urban area (P<0.05). Incidence of VSARI among suburb participants was also significant higher, especially among those of 24 to 59 months group (P<0.05).

Conclusion

Piconaviruses (EV/RV) and paramyxoviruses are the most popular viral pathogens among children with SARI in this study. RSV and hMPV significantly increase the risk of SARI, especially in children younger than 24 months. Higher incidence of VSARI and more susceptibilities to RSV and hMPV infections were found in suburban patients.     

Inhibition of airway Na+ transport by respiratory syncytial virus

In previous studies, we have shown that two major respiratory pathogens, influenza virus and parainfluenza virus, produce acute alterations in ion transport upon contacting the apical membrane of the respiratory epithelium. In the present study, we examine the effects on ion transport by the mouse tracheal epithelium of a third major respiratory pathogen, respiratory syncytial virus (RSV). RSV infections are associated with fluid accumulation in the respiratory tract and cause illnesses that range in severity from rhinitis, sinusitis, otitis media, and bronchitis to bronchiolitis and pneumonia. We find that within minutes of RSV contacting the apical membrane; it inhibits amiloride-sensitive Na+ transport by the epithelium. This effect is mediated by protein kinase C and is reproduced by recombinant viral F (fusion) protein. Since this inhibition is not accompanied by any alteration in the epithelial responses to carbachol or to forskolin plus 3-isobutyl-1-methylxanthine (IBMX), it is not due to a nonspecific toxic action of the virus. The inhibition also appears to require Toll-like receptor 4 and the presence of asialogangliosides in the apical membrane. Since the concentration range over which this inhibition is observed (10(2) to 10(5) PFU/ml) is comparable to the viral concentrations observed in clinical and experimental RSV infections, it seems likely that direct inhibition by the virus of epithelial Na+ transport may contribute to the fluid accumulation that is observed in RSV infections.