Occurrence of respiratory virus: time, place and person

Positive and negative viral associations in patients with acute respiratory tract infections in primary care: the ECOVIR study

Introduction

Acute respiratory infections (ARIs) are the most common viral infections encountered in primary care settings. The identification of causal viruses is still not available in routine practice. Although new strategies of prevention are being identified, knowledge of the relationships between respiratory viruses remains limited.

Materials and methods

ECOVIR was a multicentric prospective study in primary care, which took place during two pre-pandemic seasons (2018-2019 and 2019-2020). Patients presenting to their General practitioner (GP) with ARIs were included, without selecting for age or clinical conditions. Viruses were detected on nasal swab samples using a multiplex Polymerase Chain Reaction test focused on 17 viruses [Respiratory Syncytial Virus-A (RSV-A), RSV-B, Rhinovirus/Enterovirus (HRV), human Metapneumovirus (hMPV), Adenovirus (ADV), Coronaviruses (CoV) HKU1, NL63, 229E, OC43, Influenza virus (H1 and H3 subtypes), Influenza virus B, Para-Influenza viruses (PIVs) 1-4, and Bocavirus (BoV)].

Results

Among the 668 analyzed samples, 66% were positive for at least one virus, of which 7.9% were viral codetections. The viral detection was negatively associated with the age of patients. BoV, ADV, and HRV occurred more significantly in younger patients than the other viruses (p < 0.05). Codetections were significantly associated with RSV, HRV, BoV, hMPV, and ADV and not associated with influenza viruses, CoV, and PIVs. HRV and influenza viruses were negatively associated with all the viruses. Conversely, a positive association was found between ADV and BoV and between PIVs and BoV.

Conclusion

Our study provides additional information on the relationships between respiratory viruses, which remains limited in primary care.

Phenolic compound SG-1 from Balanophora harlandii and its derivatives exert anti-influenza A virus activity via activation of the Nrf2/HO-1 pathway

Influenza A virus (IAV) is one of the leading causes of respiratory illness and continues to cause pandemics around the world. Against this backdrop, drug resistance poses a challenge to existing antiviral drugs, and hence, there is an urgent need for developing new antiviral drugs. In this study, we obtained a phenolic compound SG-7, a derivative of natural compound 2-hydroxymethyl-1,4-hydroquinone, which exhibits inhibitory activity toward a panel of influenza viruses and has low cellular toxicity. Mechanistic studies have shown that SG-7 exerts its anti-IAV properties by acting on the virus itself and modulating host signaling pathways. Namely, SG-7 targets the HA2 subunit of hemagglutinin (HA) to block the fusion of viral-cellular membranes and inhibits IAV-induced oxidative stress and overexpression of pro-inflammatory factors by activating the Nrf2/HO-1 pathway and reducing NF-κB activation. In addition, SG-7 can enhance type I IFN antiviral response by inducing Nrf2 expression. Importantly, SG-7 showed the ability to inhibit viral replication in the lungs of IAV-infected mice and reduce their mortality. Therefore, SG-7 may be a promising lead compound for anti-influenza drug development.

Respiratory virus circulation during the first year of the COVID-19 pandemic in the Household Influenza Vaccine Evaluation (HIVE) cohort

Background

The annual reappearance of respiratory viruses has been recognized for decades. COVID-19 mitigation measures taken during the pandemic were targeted at respiratory transmission and broadly impacted the burden of acute respiratory illnesses (ARIs).

Methods

We used the longitudinal Household Influenza Vaccine Evaluation (HIVE) cohort in southeast Michigan to characterize the circulation of respiratory viruses from March 1, 2020, to June 30, 2021, using RT-PCR of respiratory specimens collected at illness onset. Participants were surveyed twice during the study period, and SARS-CoV-2 antibodies were measured in serum by electrochemiluminescence immunoassay. Incidence rates of ARI reports and virus detections were compared between the study period and a preceding pre-pandemic period of similar duration.

Results

Overall, 437 participants reported a total of 772 ARIs; 42.6% had respiratory viruses detected. Rhinoviruses were the most frequent virus, but seasonal coronaviruses, excluding SARS-CoV-2, were also common. Illness reports and percent positivity were lowest from May to August 2020, when mitigation measures were most stringent. Seropositivity for SARS-CoV-2 was 5.3% in summer 2020 and increased to 11.3% in spring 2021. The incidence rate of total reported ARIs for the study period was 50% lower (95% CI: 0.5, 0.6; p < 0.001) than the incidence rate from a pre-pandemic comparison period (March 1, 2016, to June 30, 2017).

Conclusions

The burden of ARI in the HIVE cohort during the COVID-19 pandemic fluctuated, with declines occurring concurrently with the widespread use of public health measures. Rhinovirus and seasonal coronaviruses continued to circulate even when influenza and SARS-CoV-2 circulation was low.

Respiratory Virus Circulation during the First Year of the COVID-19 Pandemic in the Household Influenza Vaccine Evaluation (HIVE) Cohort

Background

The annual reappearance of respiratory viruses has been recognized for decades. The onset of the COVID-19 pandemic altered typical respiratory virus transmission patterns. COVID-19 mitigation measures taken during the pandemic were targeted at SARS-CoV-2 respiratory transmission and thus broadly impacted the burden of acute respiratory illnesses (ARIs), in general.

Methods

We used the longitudinal Household Influenza Vaccine Evaluation (HIVE) cohort of households in southeast Michigan to characterize mitigation strategy adherence, respiratory illness burden, and the circulation of 15 respiratory viruses during the COVID-19 pandemic determined by RT-PCR of respiratory specimens collected at illness onset. Study participants were surveyed twice during the study period (March 1, 2020, to June 30, 2021), and serologic specimens were collected for antibody measurement by electrochemiluminescence immunoassay. Incidence rates of ARI reports and virus detections were calculated and compared using incidence rate ratios for the study period and a pre-pandemic period of similar length.

Results

Overall, 437 participants reported a total of 772 ARIs and 329 specimens (42.6%) had respiratory viruses detected. Rhinoviruses were the most frequently detected organism, but seasonal coronaviruses-excluding SARS-CoV-2-were also common. Illness reports and percent positivity were lowest from May to August 2020, when mitigation measures were most stringent. Study participants were more adherent to mitigation measures in the first survey compared with the second survey. Supplemental serology surveillance identified 5.3% seropositivity for SARS-CoV-2 in summer 2020; 3.0% between fall 2020 and winter 2021; and 11.3% in spring 2021. Compared to a pre-pandemic period of similar length, the incidence rate of total reported ARIs for the study period was 50% lower (95% CI: 0.5, 0.6; p<0.001) than the incidence rate from March 1, 2016, to June 30, 2017.

Conclusions

The burden of ARI in the HIVE cohort during the COVID-19 pandemic fluctuated, with declines occurring concurrently with the widespread use of public health measures. It is notable, however, that rhinovirus and seasonal coronaviruses continued to circulate even as influenza and SARS-CoV-2 circulation was low.

Maternal Vitamin D Supplementation for the Prevention of Respiratory Tract Infections in Offspring: A Meta-Analysis

BACKGROUND

Vitamin D may enhance immune system function and provide a protective effect against infections. Feto-maternal circulation plays an important role in supplying the developing fetus with nutrients and antibodies for its development and health during pregnancy and for its early years of life after birth. This meta-analysis aimed to determine the effectiveness of maternal vitamin D supplementation in preventing respiratory tract infections (RTIs) in children.

METHODS

We searched the Central and MEDLINE databases and went through all the reference lists in the related articles. We also searched for ongoing trials at http://www.who.int/ictrp/en/ and www.clinicaltrials.gov. Randomized controlled trials comparing vitamin D supplementation with a placebo or no treatment in pregnant women published in the English language up to March 2019 were included. Two reviewers extracted data independently using a predefined protocol and assessed the risk of bias using the Cochrane risk of bias tool, with differences agreed upon by consensus. The predefined primary outcome was the number of offspring who had RTIs. The secondary outcome was the presence of measurable serum immunoglobulin E levels.

RESULTS

Three trials involving 3,224 participants (mother-child pairs) met the inclusion criteria and were included in this review. The present analysis reported that maternal supplementation with vitamin D had no effect on RTIs among children (n=1,486 offspring; risk ratio, 0.95; 95% confidence interval, 0.82-1.11; random effects; I2 statistics, 0%).

CONCLUSION

Maternal vitamin D supplementation had no effect on RTIs in children. Therefore, consideration of other prevention methods in this regard is recommended.

Viral etiology of acute respiratory infections during 2014–16 in Riyadh, Saudi Arabia

Aim: Viral etiology of respiratory infections is not well understood in Saudi Arabia. This study was conceptualized to understand viral etiology in children with acute respiratory tract infections (ARTI) from Riyadh. Patients and methods: Respiratory viruses were detected by real-time PCR in nasopharyngeal aspirates or swab from 580 children aged ≤5 years. Results: Respiratory viruses were detected in 64% of the samples with 6% mixed viral infections. Respiratory syncytial virus, adenovirus, influenza, parainfluenza and human metapneumovirus infections accounted for 42, 20, 16, 12 and 10%, respectively. Maximum prevalence (37%) was among the lowest age group followed by 30% among the 7- to 12-month age group. Conclusion: The prevalence and determinants of viral etiology are in line with the previous report from the region. No major shift in the viral etiologies was observed in the 2-year study period.

Prevalence and seasonality of viral respiratory infections in a temperate climate region: A 24-year study (1997-2020)

Background

Few long‐term reports have been published on the epidemiology of respiratory viruses despite their frequent involvement in extremely common infections. The aim here was to determine the frequency and distribution of respiratory viruses in a temperate climate area (Barcelona, Spain) throughout a 24‐year period.

Methods

We collected data on all respiratory viruses detected from 1997 to 2020 in our institution. Clinical specimens were analyzed mainly by conventional techniques, and molecular techniques were also used.

Results

Of the 59,579 specimens analyzed, 21,382 (35.9%) were positive for at least one virus. The number of positive samples during cold months was significantly higher than in warm months. Respiratory virus infections were detected in patients of all ages, above all in children under 3 years of age, who were most frequently infected with the respiratory syncytial virus, whereas Influenza A virus predominated in the other groups, especially in adults. A clear demographic and seasonal pattern was established for some viruses. Circulation of other respiratory viruses during the FLUAV H1N1pdm09 and SARS‐CoV‐2 pandemics was observed.

Conclusions

This long‐term study provides new knowledge about the prevalence of respiratory viruses in a Mediterranean region. Throughout the study period, the frequency of some viruses remained constant, whereas others varied with the year. A clear demographic and seasonal pattern was established for some viruses. Patients suffering from severe respiratory infections should be examined for a range of respiratory viruses regardless of gender, age, or season.

Using Bayesian time-stratified case-crossover models to examine associations between air pollution and "asthma seasons" in a low air pollution environment

Many areas of the United States have air pollution levels typically below Environmental Protection Agency (EPA) regulatory limits. Most health effects studies of air pollution use meteorological (e.g., warm/cool) or astronomical (e.g., solstice/equinox) definitions of seasons despite evidence suggesting temporally-misaligned intra-annual periods of relative asthma burden (i.e., “asthma seasons”). We introduce asthma seasons to elucidate whether air pollutants are associated with seasonal differences in asthma emergency department (ED) visits in a low air pollution environment. Within a Bayesian time-stratified case-crossover framework, we quantify seasonal associations between highly resolved estimates of six criteria air pollutants, two weather variables, and asthma ED visits among 66,092 children ages 5–19 living in South Carolina (SC) census tracts from 2005 to 2014. Results show that coarse particulates (particulate matter <10 μm and >2.5 μm: PM_10-2.5) and nitrogen oxides (NO_x) may contribute to asthma ED visits across years, but are particularly implicated in the highest-burden fall asthma season. Fine particulate matter (<2.5 μm: PM_2.5) is only associated in the lowest-burden summer asthma season. Relatively cool and dry conditions in the summer asthma season and increased temperatures in the spring and fall asthma seasons are associated with increased ED visit odds. Few significant associations in the medium-burden winter and medium-high-burden spring asthma seasons suggest other ED visit drivers (e.g., viral infections) for each, respectively. Across rural and urban areas characterized by generally low air pollution levels, there are acute health effects associated with particulate matter, but only in the summer and fall asthma seasons and differing by PM size.

Prevalence and associated factors of acute respiratory infection among street sweepers and door-to-door waste collectors in Dessie City, Ethiopia: A comparative cross-sectional study

Background

Acute respiratory infections are rising in developing countries including Ethiopia. Lack of evidence for the prevalence and associated factors of acute respiratory infection among street sweepers and door-to-door waste collectors in Dessie City, Ethiopia is a challenge for the implementation of appropriate measures to control acute respiratory infection. Thus, this study was designed to address the gaps.

Methods

A comparative cross-sectional study was conducted among 84 door-to-door waste collectors and 84 street sweepers from March to May 2018. A simple random sampling technique was used to select study participants. Data were collected by trained data collectors using a pretested structured questionnaire and on-the-spot direct observation checklist. Data were analyzed using three different binary logistic regression models at 95% confidence interval (CI): the first model (Model I) was used to identify factors associated with acute respiratory infection among street sweepers, whereas the second model (Model II) was used to identify factors associated with acute respiratory infection among door-to-door waste collectors, and the third model (Model III) was used for pooled analysis to identify factors associated with acute respiratory infection among both street sweepers and door-to-door waste collectors. From each model multivariable logistic regression, variables with a p-value <0.05 were taken as factors significantly associated with acute respiratory infection.

Results

The overall prevalence of acute respiratory infection among studied population was 42.85% with 95% CI (35.1, 50.0%). The prevalence of acute respiratory infection among street sweepers was 48.80% (95% CI: 37.3, 64.8%) and among door-to-door waste collectors was 36.90% (95% CI: 27.4, 46.4%). There was no statistically significant difference between the prevalence of acute respiratory infection among the two groups due to the overlapping of the 95% CI. Among the street sweepers, we found that factors significantly associated with acute respiratory infection were not cleaning personal protective equipment after use (adjusted odds ratio [AOR]: 2.40; 95% CI: 1.15, 5.51) and use of coal/wood for cooking (AOR: 3.95; 95% CI: 1.52, 7.89), whereas among door-to-door waste collectors, were not using a nose/mouth mask while on duty (AOR: 5.57; 95% CI: 1.39, 9.32) and not receiving health and safety training (AOR: 3.82; 95% CI: 1.14–7.03) were factors significantly associated with acute respiratory infection among door-to-door-waste collectors. From the pooled analysis, we found that not using a nose/mouth mask while on duty (AOR: 2.19; 95% CI: 1.16, 4.53) and using coal/wood for cooking (AOR: 2.74; 95% CI: 1.18, 6.95) were factors significantly associated with acute respiratory infection for both street sweepers and door-to-door waste collectors.

Conclusion

The prevalence of acute respiratory infection among street sweepers and door-to-door waste collectors has no statistically significant difference. For both groups, not using a nose/mouth mask while on duty and using coal/wood for cooking fuel factors associated with acute respiratory infection. The municipality should motivate and monitor workers use of personal protective equipment including masks and gloves. Workers should use a nose/mouth mask while on duty and should choose a clean energy source for cooking at home.

Impact of human rhinoviruses on gene expression in pediatric patients with severe acute respiratory infection

Human rhinovirus (HRV) is one of the most common viruses, causing mild to severe respiratory tract infections in children and adults. Moreover, it can lead to patients' hospitalization. Nowadays, evaluation of gene expression alterations in host cells due to viral respiratory infections considered essential to understand the viral effects on cells.

OBJECTIVE

In this study, we aimed to find important differentially expressed genes (DEGs) related to rhinitis and asthma exacerbation stimulated with Poly (I: C) and then to validate their expression in clinical samples of children how were less than 5 years old, hospitalized with severe acute respiratory infection (SARI) due to HRV infection in comparison with healthy cases.

METHODS

Eight candidate genes involved in immunity, viral defense, inflammation, P53 pathway, and viral release processes were selected based on the analysis of a gene expression data set (GSE51392) and gene enrichment analysis. Then quantitative real-time PCR on cDNAs was performed for selected genes. The results were analyzed by Livak method and visualized by GraphPad prism software (8.4.3).

RESULT

CXCL10, CMPK2, RSAD2, SERPINA3, TNFAIP6, CXCL14, IVNS1AB, and ZMAT3 were selected based on the enrichment and topological analysis of the constructed protein-protein interaction (PPI) network. Laboratory validation by real-time PCR showed CXCL10, CMPK2, RSAD2, SERPINA3, and TNFAIP6 (belonged to immunity, inflammatory responses and viral defense) were up-regulated, whereas CXCL14 (related to immunity) and IVNS1AB, ZMAT3 (associated to Influenza and P53 pathway) were down-regulated.

CONCLUSION

Our results showed, that in children less than 5 years old affected by HRV and hospitalized with SARI, the inflammatory responses, antiviral defense, and type 1 interferon-signaling pathway have significantly affected by viral infection.

Seasonality of distinct respiratory viruses in a tropical city: implications for prophylaxis

OBJECTIVE

The frequency and seasonality of viruses in tropical regions are scarcely reported. We estimated the frequency of seven respiratory viruses and assessed seasonality of respiratory syncytial virus (RSV) and influenza viruses in a tropical city.

METHODS

Children (age ≤ 18 years) with acute respiratory infection were investigated in Salvador, Brazil, between July 2014 and June 2017. Respiratory viruses were searched by direct immunofluorescence and real-time polymerase chain reaction for detection of RSV, influenza A virus, influenza B virus, adenovirus (ADV) and parainfluenza viruses (PIV) 1, 2 and 3. Seasonal distribution was evaluated by Prais-Winsten regression. Due to similar distribution, influenza A and influenza B viruses were grouped to analyse seasonality.

RESULTS

The study group comprised 387 cases whose median (IQR) age was 26.4 (10.5-50.1) months. Respiratory viruses were detected in 106 (27.4%) cases. RSV (n = 76; 19.6%), influenza A virus (n = 11; 2.8%), influenza B virus (n = 7; 1.8%), ADV (n = 5; 1.3%), PIV 1 (n = 5; 1.3%), PIV 3 (n = 3; 0.8%) and PIV 2 (n = 1; 0.3%) were identified. Monthly count of RSV cases demonstrated seasonal distribution (b3 = 0.626; P = 0.003). More than half (42/76 [55.3%]) of all RSV cases were detected from April to June. Monthly count of influenza cases also showed seasonal distribution (b3 = -0.264; P = 0.032). Influenza cases peaked from November to January with 44.4% (8/18) of all influenza cases.

CONCLUSIONS

RSV was the most frequently detected virus. RSV and influenza viruses showed seasonal distribution. These data may be useful to plan the best time to carry out prophylaxis and to increase the number of hospital beds.

Environmental impacts on the transmission and evolution of COVID-19 combing the knowledge of pathogenic respiratory coronaviruses

The emergence of a novel coronavirus named SARS-CoV-2 during December 2019, has caused the global outbreak of coronavirus disease 2019 (COVID-19), which is officially announced to be a pandemic by the World Health Organization (WHO). The increasing burden from this pandemic is seriously affecting everyone's life, and threating the global public health. Understanding the transmission, survival, and evolution of the virus in the environment will assist in the prevention, control, treatment, and eradication of its infection. Herein, we aimed to elucidate the environmental impacts on the transmission and evolution of SARS-CoV-2, based on briefly introducing this respiratory virus. Future research objectives for the prevention and control of these contagious viruses and their related diseases are highlighted from the perspective of environmental science. This review should be of great help to prevent and control the epidemics caused by emerging respiratory coronaviruses (CoVs).

COVID-19: relationship between atmospheric temperature and daily new cases growth rate

Purpose: The novel coronavirus (severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)) first appeared in Wuhan, China, in December 2019, and rapidly spread across the globe. Since most respiratory viruses are known to show a seasonal pattern of infection, it has been hypothesised that SARS-CoV-2 may be seasonally dependent as well. The present study looks at a possible effect of atmospheric temperature, which is one of the suspected factors influencing seasonality, on the evolution of the pandemic. Basic procedures: Since confirming a seasonal pattern would take several more months of observation, we conducted an innovative day-to-day micro-correlation analysis of nine outbreak locations, across four continents and both hemispheres, in order to examine a possible relationship between atmospheric temperature (used as a proxy for seasonality) and outbreak progression. Main findings: There was a negative correlation between atmospheric temperature variations and daily new cases growth rates, in all nine outbreaks, with a median lag of 10 days. Principal conclusions: The results presented here suggest that high temperatures might dampen SARS-CoV-2 propagation, while lower temperatures might increase its transmission. Our hypothesis is that this could support a potential effect of atmospheric temperature on coronavirus disease progression, and potentially a seasonal pattern for this virus, with a peak in the cold season and rarer occurrences in the summer. This could guide government policy in both the Northern and Southern hemispheres for the months to come.

Respiratory viruses in pediatric emergency department patients and their family members

Background

Respiratory viral infections account for a substantial fraction of pediatric emergency department (ED) visits. We examined the epidemiological patterns of seven common respiratory viruses in children presenting to EDs with influenza‐like illness (ILI). Additionally, we examined the co‐occurrence of viral infections in the accompanying adults and risk factors associated with the acquisition of these viruses.

Methods

Nasopharyngeal swab were collected from children seeking medical care for ILI and their accompanying adults (Total N = 1315). Study sites included New York Presbyterian, Bellevue, and Tisch hospitals in New York City. PCR using a respiratory viral panel was conducted, and data on symptoms and medical history were collected.

Results

Respiratory viruses were detected in 399 children (62.25%) and 118 (17.5%) accompanying adults. The most frequent pathogen detected was human rhinovirus (HRV) (28.81%). Co‐infection rates were 14.79% in children and 8.47% in adults. Respiratory syncytial virus (RSV) and parainfluenza infections occurred more often in younger children. Influenza and HRV occurred more often in older children. Influenza and coronavirus were mostly isolated in winter and spring, RSV in fall and winter and HRV in fall and spring. Children with HRV were more likely to have history of asthma. Adults with the same virus as their child often accompanied ≤ 2‐year‐old‐positive children and were more likely to be symptomatic compared to adults with different viruses.

Conclusions

Respiratory viruses, while presenting the same suite of symptoms, possess distinct seasonal cycles and affect individuals differently based on a number of identifiable factors, including age and history of asthma.

Respiratory tract virus infections in the elderly with pneumonia

BACKGROUND

In children suffering from severe lower airway illnesses, respiratory virus detection has given good prognostic information, but such reports in the elderly are scarce. Therefore, our aim was to study whether the detection of nasopharyngeal viral pathogens and conventional inflammatory markers in the frail elderly correlate to the presence, signs and symptoms or prognosis of radiographically-verified pneumonia.

METHODS

Consecutive episodes of hospital care of patients 65 years and older with respiratory symptoms (N = 382) were prospectively studied as a cohort. Standard clinical questionnaire was filled by the study physician. Laboratory analyses included PCR diagnostics of nasopharyngeal swab samples for 14 respiratory viruses, C-reactive protein (CRP) and white blood cell count (WBC). Chest radiographs were systematically analysed by a study radiologist. The length of hospital stay, hospital revisit and death at ward were used as clinical endpoints.

RESULTS

Median age of the patients was 83 years (range 76-90). Pneumonia was diagnosed in 112/382 (29%) of the studied episodes. One or more respiratory viruses were detected in 141/382 (37%) episodes and in 34/112 (30%) episodes also diagnosed with pneumonia. Pneumonia was associated with a WBC over 15 × 10⁹/L (P = .006) and a CRP value over 80 mg/l (P < .05). A virus was detected in 30% of pneumonia episodes and in 40% of non-pneumonia episodes, but this difference was not significant (P = 0.09). The presence of a respiratory virus was associated with fewer revisits to the hospital (P < .05), whereas a CRP value over 100 mg/l was associated with death during hospital stay (P < .05). Respiratory virus detections did not correlate to WBC or CRP values, signs and symptoms or prognosis of radiographically-verified pneumonia episodes.

CONCLUSION

Among the elderly with respiratory symptoms, respiratory virus detection was not associated with an increased risk of pneumonia or with a more severe clinical course of the illness. CRP and WBC remain important indicators of pneumonia, and according to our findings, pneumonia should be treated as a bacterial disease regardless of the virus findings. Our data does not support routine virus diagnostics for the elderly patients with pneumonia outside the epidemic seasons.

Epidemiology of human respiratory viruses in children with acute respiratory tract infection in a 3-year hospital-based survey in Northern Italy

Acute respiratory tract infections (ARTIs) are among the leading causes of morbidity and mortality in children. The viral etiology of ARTIs was investigated over 3 years (October 2012–September 2015) in 2575 children in Parma, Italy, using indirect immunofluorescent staining of respiratory samples for viral antigens, cell culture, and molecular assays. Respiratory viruses were detected in 1299 cases (50.44%); 1037 (79.83%) were single infections and 262 (20.17%) mixed infections. The highest infection incidence was in children aged >6 months to ≤3 years (57.36%). Human respiratory syncytial virus (27.12%) and human adenovirus (23.58%) were the most common viruses identified. The virus detection rate decreased significantly between the first and third epidemic season (53.9% vs. 43.05%, P < 0.0001). The simultaneous use of different diagnostic tools allowed us to identify a putative viral etiology in half the children examined and to provide an estimate of the epidemiology and seasonality of respiratory viruses associated with ARTIs.

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Respiratory viruses were assessed in children from October 2012 to September 2015.

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Viruses were detected using antigen and molecular assays, and cell culture.

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Respiratory syncytial virus and adenovirus were the most common viruses detected.

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Influenza virus and respiratory syncytial virus detection showed seasonal variation.

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Respiratory virus detection was highest in children aged >6 months to ≤3 years.

School sessions are correlated with seasonal outbreaks of medically attended respiratory infections: electronic health record time series analysis, Wisconsin 2004-2011

Increased social contact within school settings is thought to be an important factor in seasonal outbreaks of acute respiratory infection (ARI). To better understand the degree of impact, we analysed electronic health records and compared risks of respiratory infections within communities while schools were in session and out-of-session. A time series analysis of weekly respiratory infection diagnoses from 28 family medicine clinics in Wisconsin showed that people under the age of 65 experienced an increased risk of ARI when schools were in session. For children aged 5-17 years, the risk ratio for the first week of a school session was 1.12 (95% confidence interval (CI) 0.93-1.34), the second week of a session was 1.39 (95% CI 1.15-1.68) and more than 2 weeks into a session was 1.43 (95% CI 1.20-1.71). Less significant increased risk ratios were also observed in young children (0-4 years) and adults (18-64 years). These results were obtained after modelling for baseline seasonal variations in disease prevalence and controlling for short-term changes in ambient temperature and relative humidity. Understanding the mechanisms of seasonality make it easier to predict outbreaks and launch timely public health interventions.

Respiratory viral infections in infants with possible sepsis

Background

Knowledge of infections leading to sepsis is needed to develop comprehensive infection prevention and sepsis, as well as early recognition and treatment strategies.The aim of this study was to investigate the etiology of sepsis and evaluate the proportion of respiratory viral pathogens in infants under two years of age with possible sepsis.

Methods

The prospective study was performed in two years. Multiplex reverse transcriptase polymerase chain reaction (RT‐PCR) was performed to detect viral pathogens. All patients who were included in this study had sepsis symptoms as defined by the Surviving Sepsis Campaign.

Results

We compared 90 patients with sepsis into three groups as patients (n = 33) who had only viral positivity in nasopharyngeal swab, patients (17) had proven bacterial infection with or without viral infection, and patients (40) without the pathogen detection. Human rhinovirus (16.7%) and influenza (7.8%) were the most commonly seen viruses. A cough was more common in the viral infection group than other groups ( P = 0.02) and median thrombocyte count was lower in the bacterial infection group than the others ( P = 0.01). Patients having bacterial sepsis had the longest duration of hospitalization than the other groups ( P = 0.04). During winter and spring seaons, patients with sepsis had more viral infection; however, in summer and autumn period, patients were mostly in a state that we could not prove infection agents ( P = 0.02).

Conclusions

Our results suggest that respiratory tract viruses may play an important role in patients with sepsis and they should be kept in mind, especially during winter and spring seasons. In overall infection, viral respiratory viruses as a single pathogen with a detection rate of 36.6% in sepsis etiology.

Rotavirus infection as a frequent cause of neonatal fever

BACKGROUND

Fever rather than diarrhea or vomiting was the most common symptom of neonatal rotavirus (RV) infection in our previous study. We investigated whether RV infection is a major cause of neonatal fever and compared the clinical characteristics of bacterial infection, viral infection and unknown causes of neonatal fever.

METHOD

We reviewed the electronic medical records of 48 newborns aged ≤28 days who were admitted to the Special Care Nursery of Hanyang University Guri Hospital for fever (≥38°C) from 2005 to 2009. All the newborns underwent complete blood count, urinalysis, C-reactive protein, cultures of blood, urine, and cerebrospinal fluid as well as stool RV enzyme-linked immunosorbent assay. Respiratory virus polymerase chain reaction for cough or rhinorrhea, and stool culture for diarrhea were also done.

RESULTS

All the babies were term, with mean age 13 ± 8 days and peak body temperature 38.5 ± 0.5°C. The causes of neonatal fever were viral (44%), bacterial (10%) and unknown (46%). The viral infections included RV (n = 12), enterovirus (n = 6), respiratory syncytial virus (n = 2), and rhinovirus (n = 1). All the rotavirus genotypes were G4P[6]. Only three of 12 RV-infected febrile newborns had diarrhea. The bacterial infections included three cases of urinary tract infection (Escherichia coli, n = 2; Klebsiella pneumoniae, n = 1), and two cases of sepsis complicated with meningitis (all Streptococcus agalactiae).

CONCLUSIONS

RV infection is the most common single cause of neonatal fever. It may be necessary to include stool RV tests for febrile newborns.

Investigation of markers of allergic sensitization and viral infections in children with allergy and asthma

Background.

Allergic diseases are the most prevalent chronic diseases in the developed countries. It is believed that early allergic sensitization and respiratory viral infections play an important role in the development of allergic diseases and asthma.

Methods.

The current study investigated the correlation between asthma, allergy, and various markers – allergen-specific IgE, IgG4 and IgA, ECP, IgM, and IgG antibodies against respiratory viruses hRSV and hPIV1-4 – in blood serum samples from 80 children (mean age 5.2 years) recruited from the Lithuanian birth cohort. Children were divided into three groups according to their diagnosis: asthma (n = 25), allergy without asthma (n = 14), and control group (n = 41).

Results.

Based on retrospective data, airway infections and bronchitis by the age of two years were associated with asthma in later childhood. The presence of IgM and IgG antibodies against hRSV and hPIV1–4 at the age of five years were not associated with asthma and allergy: a high rate of persistent or past respiratory viral infections was revealed in all three groups. Among allergic children, increased levels of allergen-specific IgE and d1-specific IgG4 were determined.

Conclusion.

The current study provides new insights into the relationships between allergic sensitization and respiratory virus infections in children.

Evaluation of the New World Health Organization Case Definition of Severe Acute Respiratory Infection for Influenza Surveillance During the Peak Weeks of Two Influenza Seasons in Quebec, Canada

During the peak of the 2012-2013 and 2014-2015 influenza seasons in Quebec, Canada, the sensitivity of the new World Health Organization (WHO) case definition of severe acute respiratory infection (SARI) in <5-year-old children was 65% for polymerase chain reaction-confirmed influenza and 79% for other respiratory viruses (ORVs), whereas its specificity and positive predictive value were approximately 2- and 4-fold lower for influenza than ORVs (25% vs 40% and 18% vs 76%, respectively). The use of the WHO SARI definition for influenza surveillance in children should be interpreted with caution according to the specific surveillance goals.

Respiratory RNA Viruses

Acute upper and lower respiratory infections are a major public health problem and a leading cause of morbidity and mortality worldwide. At greatest risk are young children, the elderly, the chronically ill, and those with suppressed or compromised immune systems. Viruses are the predominant cause of respiratory tract illnesses and include RNA viruses such as respiratory syncytial virus, influenza virus, parainfluenza virus, metapneumovirus, rhinovirus, and coronavirus. Laboratory testing is required for a reliable diagnosis of viral respiratory infections, as a clinical diagnosis can be difficult since signs and symptoms are often overlapping and not specific for any one virus. Recent advances in technology have resulted in the development of newer diagnostic assays that offer great promise for rapid and accurate detection of respiratory viral infections. This chapter emphasizes the fundamental characteristics and clinical importance of the various RNA viruses that cause upper and lower respiratory tract diseases in the immunocompromised host. It highlights the laboratory methods that can be used to make a rapid and definitive diagnosis for the greatest impact on the care and management of ill patients, and the prevention and control of hospital-acquired infections and community outbreaks.

Differences in emergency ambulance demand between older adults living in residential aged care facilities and those living in the community in Melbourne, Australia

OBJECTIVE

To describe the clinical presentation and temporal variation in ambulance service cases involving patients aged 65 years or older (older adults) from residential aged care facilities and those who are community dwelling (CD).

METHODS

This study used four years of electronic case records from Ambulance Victoria in Melbourne, Australia. Trigonometric regression was used to analyse demand patterns.

RESULTS

Residential aged care facility cases included proportionally more falls and infection-related problems and fewer circulatory-related incidents than CD cases. Community dwelling demand patterns differed between weekdays and weekends and peaked late morning. Residential aged care facility cases peaked late morning, with a secondary peak early evening, but with no significant difference between days.

CONCLUSIONS

Older adult ambulance demand has distinct temporal patterns that differ by place of residence and are associated with different clinical presentations. These results provide a basis for informing ambulance planning and the identification of alternate health services.

Interference Between Respiratory Syncytial Virus and Human Rhinovirus Infection in Infancy

BACKGROUND

Respiratory syncytial virus (RSV) and human rhinovirus (HRV) are the most common viruses associated with acute respiratory tract infections in infancy. Viral interference is important in understanding respiratory viral circulation and the impact of vaccines.

METHODS

To study viral interference, we evaluated cases of RSV and HRV codetection by polymerase chain reaction in 2 prospective birth cohort studies (the Infant Susceptibility to Pulmonary Infections and Asthma Following RSV Exposure [INSPIRE] study and the Tennessee Children's Respiratory Initiative [TCRI]) and a double-blinded, randomized, controlled trial (MAKI), using adjusted multivariable regression analyses.

RESULTS

Among 3263 respiratory tract samples, 24.5% (798) and 37.3% (1216) were RSV and HRV positive, respectively. The odds of HRV infection were significantly lower in RSV-infected infants in all cohorts, with adjusted odds ratios of 0.30 (95% confidence interval [CI], .22-.40 in the INSPIRE study, 0.18 (95% CI, .11-.28) in the TCRI (adjusted for disease severity), and 0.34 (95% CI, .16-.72) in the MAKI trial. HRV infection was significantly more common among infants administered RSV immunoprophylaxis, compared with infants who did not receive immunoprophylaxis (OR, 1.65; 95% CI, 1.65-2.39).

CONCLUSIONS

A negative association of RSV on HRV codetection was consistently observed across populations, seasons, disease severity, and geographical regions. Suppressing RSV infection by RSV immunoprophylaxis might increase the risk of having HRV infection.

Multiple Viral Infection Detected from Influenza-Like Illness Cases in Indonesia

Influenza is one of the common etiologies of the upper respiratory tract infection (URTI). However, influenza virus only contributes about 20 percent of influenza-like illness patients. The aim of the study is to investigate the other viral etiologies from ILI cases in Indonesia. Of the 334 samples, 266 samples (78%) were positive at least for one virus, including 107 (42%) cases of multiple infections. Influenza virus is the most detected virus. The most frequent combination of viruses identified was adenovirus and human rhinovirus. This recent study demonstrated high detection rate of several respiratory viruses from ILI cases in Indonesia. Further studies to determine the relationship between viruses and clinical features are needed to improve respiratory disease control program.

Temporal cross-correlation between influenza-like illnesses and invasive pneumococcal disease in The Netherlands

Background

While the burden of community‐acquired pneumonia and invasive pneumococcal disease (IPD) is still considerable, there is little insight in the factors contributing to disease. Previous research on the lagged relationship between respiratory viruses and pneumococcal disease incidence is inconclusive, and studies correcting for temporal autocorrelation are lacking.

Objectives

To investigate the temporal relation between influenza‐like illnesses (ILI) and IPD, correcting for temporal autocorrelation.

Methods

Weekly counts of ILI were obtained from the Sentinel Practices of NIVEL Primary Care Database. IPD data were collected from the Dutch laboratory‐based surveillance system for bacterial meningitis from 2004 to 2014. We analysed the correlation between time series, pre‐whitening the dependent time series with the best‐fit seasonal autoregressive integrated moving average (SARIMA) model to the independent time series. We performed cross‐correlations between ILI and IPD incidences, and the (pre‐whitened) residuals, in the overall population and in the elderly.

Results

We found significant cross‐correlations between ILI and IPD incidences peaking at lags ‐3 overall and at 1 week in the 65+ population. However, after pre‐whitening, no cross‐correlations were apparent in either population group.

Conclusion

Our study suggests that ILI occurrence does not seem to be the major driver of IPD incidence in The Netherlands.

Temporal association between the influenza virus and respiratory syncytial virus (RSV): RSV as a predictor of seasonal influenza

Epidemiologists agree that there is a prevailing seasonality in the presentation of epidemic waves of respiratory syncytial virus (RSV) infections and influenza. The aim of this study is to quantify the potential relationship between the activity of RSV, with respect to the influenza virus, in order to use the RSV seasonal curve as a predictor of the evolution of an influenza virus epidemic wave. Two statistical tools, logistic regression and time series, are used for predicting the evolution of influenza. Both logistic models and time series of influenza consider RSV information from previous weeks. Data consist of influenza and confirmed RSV cases reported in Comunitat Valenciana (Spain) during the period from week 40 (2010) to week 8 (2014). Binomial logistic regression models used to predict the two states of influenza wave, basal or peak, result in a rate of correct classification higher than 92% with the validation set. When a finer three-states categorization is established, basal, increasing peak and decreasing peak, the multinomial logistic model performs well in 88% of cases of the validation set. The ARMAX model fits well for influenza waves and shows good performance for short-term forecasts up to 3 weeks. The seasonal evolution of influenza virus can be predicted a minimum of 4 weeks in advance using logistic models based on RSV. It would be necessary to study more inter-pandemic seasons to establish a stronger relationship between the epidemic waves of both viruses.

Audiometric Patterns and Prognosis in Sudden Sensorineural Hearing Loss in Southern Taiwan

OBJECTIVES: To investigate factors affecting the prognosis of sudden sensorineural hearing loss (SSNHL).

STUDY DESIGN AND SETTING: This is a retrospective study of patients with SSNHL hospitalized at an academic medical center. All patients in this study were treated with prednisolone and dextran. We compared a new 7-pattern classification for audiometric pattern and prognosis analysis with Sheehy classification.

RESULTS: We analyzed 148 affected ears in 146 patients. Occurrence of SSNHL was associated with changes in season. The best prognosis was with the midtone pattern of the 7-pattern classification and with the low-tone pattern of Sheehy classification. The older patients, those with vertigo, or those treated after 6 days had a poor prognosis. There was no significant association between ESR level and prognosis.

CONCLUSIONS: SSNHL patients with midtone loss have the best prognosis. This study of the audiometric patterns and prognostic factors of SSNHL allow us to better predict its outcome.

EBM RATING: B-2

Vitamin D and airway infections: a European perspective

Vitamin D has immuno-modulatory properties, and deficient levels of circulating 25-hydroxyvitamin D (<30 nmol/l) may contribute to increased risk of infectious illnesses. This narrative review summarises data on vitamin D status in Europe and updates results of randomised controlled trials (RCTs) regarding vitamin D and airway infections such as tuberculosis (TB) and acute upper respiratory tract infection. In Europe, the prevalence of vitamin D deficiency is up to 37% in the general population and up to 80% in nursing home residents and non-European immigrants. Half of TB patients have a migration background. While results of RCTs do not support the concept of beneficial adjunctive effects of vitamin D supplements in anti-TB treatment [odds ratio (OR) = 0.86; 95% CI 0.62-1.19], the few published RCTs on the prophylaxis of TB suggest some protective vitamin D effects in individuals with deficient circulating 25-hydroxyvitamin D levels. Regarding acute respiratory tract infection, RCTs indicate a significant risk reduction by vitamin D supplements [OR = 0.65; 95% confidence interval (CI) 0.50-0.85]. There is evidence that daily administration is more effective than high-dose bolus administration [OR = 0.48 (95% CI 0.30-0.77) vs. OR = 0.87 (95% CI 0.67-1.14)] and that individuals with deficient or insufficient (30-50 nmol/l) circulating 25-hydroxyvitamin D levels benefit most. Several vitamin D effects on innate immunity may explain these protective effects. In summary, there is possible evidence from RCTs for protective vitamin D effects on TB and likely evidence for protective effects on acute airway infection. Since vitamin D deficiency is prevalent in Europe, especially in institutionalised individuals and non-European immigrants, daily oral vitamin D intake, e.g. 1000 international units, is an inexpensive measure to ensure adequate vitamin D status in individuals at risk.

Evaluation of a fluorescent immunoassay rapid test (Sofia™) for detection of influenza A+B and RSV in a tertiary pediatric setting

In response to the lack of sensitivity and reproducibility of previously marketed rapid antigen detection tests, a novel fluorescent immunoassay was recently developed. This new assay offers rapidity and automated reading. More characterization of this assay is needed. The aim of this study was to assess diagnostic performance of Sofia influenza A+B and respiratory syncytial virus (RSV) while compared to traditional viral cell culture. A total of 416 respiratory samples were analyzed prospectively with both methods in a tertiary pediatric center. Sensitivity and specificity of the Sofia™ test were 90.0% and 98.0% for influenza A, 90.9% and 98.9% for influenza B, and 87.7% and 94.7% for RSV compared to traditional cell culture. Overall, Sofia influenza A+B and RSV assays performed well in comparison to culture in a pediatric population.

Viral Etiology of acute respiratory tract infections in hospitalized children and adults in Shandong Province, China

Background

The dominant viral etiologies responsible for acute respiratory infections (ARIs) are poorly understood, particularly among hospitalized patients. Improved etiological insight is needed to improve clinical management and prevention of ARIs.

Methods

Clinical and demographic information and throat swabs were collected from 607 patients from 2011 to 2013 in Shandong Province, China. Multiplex RT-PCR (SeeplexTM RV detection, Seegene) was performed to detected 12 respiratory viral pathogens.

Results

A total of 607 hospitalized patients were enrolled from 2011 to 2013. Viruses were identified in 35.75 % (217/607) of cases, including 78 influenza virus A and B (IVA and IVB), 47 para-influenza viruses (PIVs), 41 respiratory syncytial virus (RSV) and 38 adenovirus (ADV). For the children under 15 year old, the common detected viruses were influenza viruses, RSV, PIVS and ADV, while the principal respiratory viruses were human coronaviruses (HCoV), PIVs, influenza viruses for the old adults. Co-infections with multiple viruses were detected in 15.67 % of patients. Children under 5 years were more likely to have one or more detectable virus associated with their ARI. The peak of ARI caused by the respiratory viruses occurred in winter.

Conclusion

This study demonstrated respiratory viruses were the major cause of hospitalized ARI patients in Shandong Province, influenza virus was the most common detected, RSV was the highest incidence among the young children (≤5 years). These findings also gave a better understand of virus distribution among different age and seasons, which help to consider potential therapeutic approaches and develop effective prevention strategies for respiratory virus infection.

Ten-year performance of Influenzanet: ILI time series, risks, vaccine effects, and care-seeking behaviour

Recent public health threats have propelled major innovations on infectious disease monitoring, culminating in the development of innovative syndromic surveillance methods. Influenzanet is an internet-based system that monitors influenza-like illness (ILI) in cohorts of self-reporting volunteers in European countries since 2003. We investigate and confirm coherence through the first ten years in comparison with ILI data from the European Influenza Surveillance Network and demonstrate country-specific behaviour of participants with ILI regarding medical care seeking. Using regression analysis, we determine that chronic diseases, being a child, living with children, being female, smoking and pets at home, are all independent predictors of ILI risk, whereas practicing sports and walking or bicycling for locomotion are associated with a small risk reduction. No effect for using public transportation or living alone was found. Furthermore, we determine the vaccine effectiveness for ILI for each season.

Impact of the 2009 H1N1 Pandemic on Age-Specific Epidemic Curves of Other Respiratory Viruses: A Comparison of Pre-Pandemic, Pandemic and Post-Pandemic Periods in a Subtropical City

BACKGROUND

The 2009 H1N1 influenza pandemic caused offseason peaks in temperate regions but coincided with the summer epidemic of seasonal influenza and other common respiratory viruses in subtropical Hong Kong. This study was aimed to investigate the impact of the pandemic on age-specific epidemic curves of other respiratory viruses.

METHODS

Weekly laboratory-confirmed cases of influenza A (subtypes seasonal A(H1N1), A(H3N2), pandemic virus A(H1N1)pdm09), influenza B, respiratory syncytial virus (RSV), adenovirus and parainfluenza were obtained from 2004 to 2013. Age-specific epidemic curves of viruses other than A(H1N1)pdm09 were compared between the pre-pandemic (May 2004-April 2009), pandemic (May 2009-April 2010) and post-pandemic periods (May 2010-April 2013).

RESULTS

There were two peaks of A(H1N1)pdm09 in Hong Kong, the first in September 2009 and the second in February 2011. The infection rate was found highest in young children in both waves, but markedly fewer cases in school children were recorded in the second wave than in the first wave. Positive proportions of viruses other than A(H1N1)pdm09 markedly decreased in all age groups during the first pandemic wave. After the first wave of the pandemic, the positive proportion of A(H3N2) increased, but those of B and RSV remained slightly lower than their pre-pandemic proportions. Changes in seasonal pattern and epidemic peak time were also observed, but inconsistent across virus-age groups.

CONCLUSION

Our findings provide some evidence that age distribution, seasonal pattern and peak time of other respiratory viruses have changed since the pandemic. These changes could be the result of immune interference and changing health seeking behavior, but the mechanism behind still needs further investigations.

Detection of influenza vaccine effectiveness among nursery school children: Lesson from a season with cocirculating respiratory syncytial virus

In the winter influenza epidemic season, patients with respiratory illnesses including respiratory syncytial virus (RSV) infections increase among young children. Therefore, we evaluated the effectiveness of influenza vaccine against influenza-like illness (ILI) using a technique to identify outbreaks of RSV infection and to distinguish those patients from ILI patients. The study subjects were 101 children aged 12 to 84 months attending nursery school. We classified the cases into 6 levels based on the definitions of ILI for outcomes. We established observation periods according to information obtained from regional surveillance and rapid diagnostic tests among children. Multivariate odds ratios (ORs) for each case classification were obtained using a logistic regression model for each observation period. For the entire observation period, ORs for cases with fever plus respiratory symptoms were reduced marginally significantly. For the local influenza epidemic period, only the OR for the most serious cases was significantly decreased (0.20 [95%CI: 0.04-0.94]). During the influenza outbreak among the nursery school children, multivariate ORs for fever plus respiratory symptoms decreased significantly (≥ 38.0°C plus ≥ one symptoms: 0.23 [0.06-0.91), ≥ 38.0°C plus ≥ 2 symptoms: 0.21 [0.05-0.85], ≥ 39.0°C plus ≥ one symptoms: 0.18 [0.04-0.93] and ≥ 39.0°C plus ≥ 2 symptoms: 0.16 [0.03-0.87]). These results suggest that confining observation to the peak influenza epidemic period and adoption of a strict case classification system can minimize outcome misclassification when evaluating the effectiveness of influenza vaccine against ILI, even if influenza and RSV cocirculate in the same season.

Frequency of acute respiratory illnesses and circulation of respiratory viruses in households with children over 3 surveillance seasons

BACKGROUND

The household has traditionally been the site for studying acute respiratory illnesses (ARIs). Most studies were conducted many years ago, and more broadly sensitive laboratory methods to determine ARI etiology are now available.

METHODS

We recruited and followed households with children over 3 annual surveillance periods and collected respiratory tract specimens from subjects with reported ARI. Virus etiology was determined by real-time reverse-transcription polymerase chain reaction (RT-PCR) analysis.

RESULTS

Individuals in larger households (defined as households with >4 members) and those in households with children aged <5 years had significantly higher ARI frequencies than others. ARI frequency generally declined with increasing age. Virus etiology was most likely to be determined in young children, who were also most likely to have virus coinfection. Overall, 16% of ARIs with 1 virus identified had ≥1 coinfecting virus. Rhinoviruses and coronaviruses were the most frequently identified agents of ARI in all age categories. Influenza virus and adenovirus were less frequently identified but were most likely to cause ARI that required medical attention.

CONCLUSIONS

Longitudinal studies in families remain a valuable way to study respiratory infections. RT-PCR has increased the sensitivity of virus detection, including coinfecting viruses, and expanded our ability to detect viruses now known to cause ARI.

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.

The Epidemiology of Upper Respiratory Infections at a Tertiary Care Center: Prevalence, Seasonality, and Clinical Symptoms

Improved multiplex PCR detection methods are facilitating the correlation of the etiology of respiratory tract infections with specific symptoms or clinical manifestations. We conducted a retrospective analysis of the incidence of respiratory pathogens and initial symptoms in 1,286 patients at a tertiary care center tested by multiplex respiratory pathogen PCR from July 1, 2012, to June 30, 2013. Rhinovirus/enterovirus (Rhino/Entero) infections were the most prevalent (25.4%) followed by respiratory syncytial virus (RSV) (13.6%) and influenza A (6.2%). Eleven percent of patients were positive for multiple analytes with Rhino/Entero and RSV being the most common combination. Asthma or asthma exacerbation was the most common presenting symptom in patients positive for Rhino/Entero (38.4%) or positive for Rhino/Entero along with RSV or hMPV (34.8%). Of the patients positive for Rhino/Entero and presenting with asthma, 97% were ≤17 years of age. RSV positive patients most commonly presented with respiratory distress (40.3%) followed by asthma (18%) or pneumonia (18%). The most prevalent initial clinical manifestation for influenza was fever (27.4%) followed by respiratory distress (13%) or pneumonia (11.9%). The significant percentage of patients positive for Rhino/Entero virus presenting with asthma supports the role of rhinovirus as an important trigger for asthma exacerbation.

A 3-year prospective study of the epidemiology of acute respiratory viral infections in hospitalized children in Shenzhen, China

Background

The epidemiology of local viral etiologies is essential for the management of viral respiratory tract infections. Limited data are available in China to describe the epidemiology of viral respiratory infections, especially in small–medium cities and rural areas.

Objectives

To determine the viral etiology and seasonality of acute respiratory infections in hospitalized children, a 3-year study was conducted in Shenzhen, China.

Methods

Nasopharyngeal aspirates from eligible children were collected. Influenza and other respiratory viruses were tested by molecular assays simultaneously. Data were analyzed to describe the frequency and seasonality.

Results

Of the 2025 children enrolled in the study, 971 (48·0%) were positive for at least one viral pathogen, in which 890 (91·7%) were <4 years of age. The three most prevalent viruses were influenza A (IAV; 35·8%), respiratory syncytial virus (RSV; 30·5%) and human rhinovirus (HRV; 21·5%). Co-infections were found in 302 cases (31·1%), and dual viral infection was dominant. RSV, HRV and IAV were the most frequent viral agents involved in co-infection. On the whole, the obvious seasonal peaks mainly from March to May were observed with peak strength varying from 1 year to another.

Conclusions

This study provides a basic profile of the epidemiology of acute respiratory viral infection in hospitalized children in Shenzhen. The spectrum of viruses in the study site is similar to that in other places, but the seasonality is closely related to geographic position, different from that in big cities in northern China and neighboring Hong Kong.

Human rhino- and enteroviruses in children with respiratory symptoms in Luanda, Angola

OBJECTIVES

The role of human rhinoviruses (HRV) and human enteroviruses (HEV) in common colds, as well as their seasonality, remains largely unknown in tropical environments. The study aimed to define the frequency and clinical features of HRV and HEV in children with respiratory symptoms in tropical Africa during autumn and winter.

METHODS

Clinical data and PCR assays of nasopharyngeal swabs (NPS) were collected from 67 (66%) children with and 35 (34%) children without chronic illnesses who were attending different outpatient clinics at a paediatric tertiary-care hospital in Luanda, Angola.

RESULTS

Thirty-six (35%) children had HIV infection, and 27 (26%) were malnourished. Thirty-seven (36%) out of 102 NPS specimens were virus-positive: 34 (33%) for HRV and 10 (10%) for HEV. Seven (7%) had co-infection. The highest HRV-positivity rate (47%) occurred in July (P = 0·02), a mid-winter month with high relative humidity but no precipitation. Virus positivity was associated with younger age (median 36 vs 52 months, P = 0·02) but not with specific symptoms or findings.

CONCLUSIONS

HRVs play a major role in young children's respiratory infections in urban tropical Angola during autumn and winter. A better understanding is required of the seasonality and clinical outcomes of these viruses in children living in resource-poor tropical countries.

Viruses associated with acute respiratory infections and influenza-like illness among outpatients from the Influenza Incidence Surveillance Project, 2010-2011

Background. The Influenza Incidence Surveillance Project (IISP) monitored outpatient acute respiratory infection (ARI; defined as the presence of ≥2 respiratory symptoms not meeting ILI criteria) and influenza-like illness (ILI) to determine the incidence and contribution of associated viral etiologies.

Methods. From August 2010 through July 2011, 57 outpatient healthcare providers in 12 US sites reported weekly the number of visits for ILI and ARI and collected respiratory specimens on a subset for viral testing. The incidence was estimated using the number of patients in the practice as the denominator, and the virus-specific incidence of clinic visits was extrapolated from the proportion of patients testing positive.

Results. The age-adjusted cumulative incidence of outpatient visits for ARI and ILI combined was 95/1000 persons, with a viral etiology identified in 58% of specimens. Most frequently detected were rhinoviruses/enteroviruses (RV/EV) (21%) and influenza viruses (21%); the resulting extrapolated incidence of outpatient visits was 20 and 19/1000 persons respectively. The incidence of influenza virus-associated clinic visits was highest among patients aged 2–17 years, whereas other viruses had varied patterns among age groups.

Conclusions. The IISP provides a unique opportunity to estimate the outpatient respiratory illness burden by etiology. Influenza virus infection and RV/EV infection(s) represent a substantial burden of respiratory disease in the US outpatient setting, particularly among children.

Human parainfluenza virus in patients with influenza-like illness from Central and South America during 2006-2010

Background

Human parainfluenza viruses (HPIVs) are common viral causes of community-acquired pneumonia, particularly in children. The four types of HPIV have world-wide distribution; however, limited information exists about the epidemiological profile of HPIV in Latin-America.

Objective

Provide epidemiologic and phylogenetic information about HPIVs that circulated in Latin America between 2006 and 2010 to better characterize the extent and variability of this respiratory virus in the region.

Methods

Oropharyngeal swabs, demographic data and clinical characteristics were obtained from individuals with influenza-like illness in 10 Latin-American countries between 2006–2010. Specimens were analyzed with culture and molecular methods.

Results

A total of 30 561 individuals were enrolled; 991 (3·2%) were HPIV positive. Most infected participants were male (53·7%) and under 5 years of age (68·7%). The HPIV type most frequently isolated was HPIV-3 (403, 40·7%). In 66/2007 (3·3%) hospitalized individuals, HPIV was identified. The most frequent symptoms at enrollment were cough and rhinorrhea. We identified certain patterns for HPIV-1, -2 and -3 in specific cities. Phylogenetic analysis revealed a homogeneous distribution in the region.

Conclusions

In the current scenario, no vaccine or treatment is available for this pathogen. Our results contribute to the scarce epidemiologic and phylogenetic information of HPIV in the region that could support the development of specific management.

Overweight/obesity and risk of seasonal asthma exacerbations

BACKGROUND

Obesity is associated with an increased risk for asthma exacerbations, but whether this risk is related to the season of exacerbation is not known.

OBJECTIVE

To determine the relationship of increased body mass index (BMI) to the season of asthma exacerbation.

METHODS

Study subjects were adult (aged 18-65 years) and children (aged 5-17 years) health plan members with persistent asthma in 2008 for whom a BMI measurement was available. BMI categories were normal (<25 kg/m(2)), overweight (25-29.9 kg/m(2)), and obese (≥30 kg/m(2)). Exacerbations were defined as oral corticosteroid dispensings linked to an asthma encounter in the spring, summer, fall, or winter of 2009.

RESULTS

The cohort included 17,316 adults and 10,700 children. There was a significant (P < .05) linear increase with BMI category in the proportion of adults with exacerbations in every season and in the proportion of children with exacerbations during fall and winter. Relationships of overweight or obesity (vs normal weight) to fall and winter exacerbations remained significant in both adults and children after adjustment for sex and education. In a generalized estimating equation model, both BMI status and season (spring, fall, and winter) were related to exacerbations. Moreover, we noted a significant interaction in adults (P = .03) but not children (P = .97) of the BMI-exacerbation association by season (fall-winter vs spring-summer).

CONCLUSION

Higher BMI values increased the risk for asthma exacerbations in adults and children with persistent asthma, particularly for fall-winter exacerbations in adults. Potential mechanisms for these findings, including vitamin D status, viral infections, and corticosteroid responsiveness, merit further study.

Viral etiology of influenza-like illnesses during the influenza season between December 2011 and April 2012

The aim of this study was to determine the frequency of respiratory viruses responsible for respiratory tract infections in Turkish children during the 2011–2012 influenza season. Nasal swabs were obtained from patients with symptoms suggestive of an influenza‐like illness between December 2011 and April 2012. Samples were analyzed with multiplex real‐time polymerase chain reaction (RT‐PCR) to help identify the causative viral pathogen. A total of 200 patients were enrolled in the study. A respiratory virus was detected successfully in 102 (51%) children; influenza A (H3N2) in 39.2%, influenza B in 23.5%, RSV in 15.6%, rhinovirus in 13.7%, bocavirus in 2.9%, coronavirus in 2.9%, and metapneumovirus in 0.9% of patients. Only one patient was co‐infected with bocavirus and influenza A virus. A statistically significant difference in the mean age of presentation was observed between the various viral pathogens (P < 0.001). Patients with RSV were significantly younger whereas children infected with the influenza viruses were significantly older. Comparison of symptoms revealed that fever and headache occurred more frequently with the influenza viruses than the other viruses combined (P < 0.001, <0.05). Durations of symptoms such as fever, cough, nasal congestion, and rhinorrhea were also significantly longer in the influenza group (P < 0.001, <0.005, <0.001, <0.005, respectively). Demographic analyses revealed that the school/daycare attendance was the only parameter associated with a significantly increased risk for influenza infection. With an overall viral pathogen detection rate of 51%, findings of the present study suggest other respiratory pathogens, whether viral or bacterial, may also lead to hospital visits due to influenza‐like illnesses in children. J. Med. Virol. 86:865–871, 2014. © 2013 Wiley Periodicals, Inc.

Molecular epidemiology of respiratory viruses in virus-induced asthma

Acute respiratory illness (ARI) due to various viruses is not only the most common cause of upper respiratory infection in humans but is also a major cause of morbidity and mortality, leading to diseases such as bronchiolitis and pneumonia. Previous studies have shown that respiratory syncytial virus (RSV), human rhinovirus (HRV), human metapneumovirus (HMPV), human parainfluenza virus (HPIV), and human enterovirus infections may be associated with virus-induced asthma. For example, it has been suggested that HRV infection is detected in the acute exacerbation of asthma and infection is prolonged. Thus it is believed that the main etiological cause of asthma is ARI viruses. Furthermore, the number of asthma patients in most industrial countries has greatly increased, resulting in a morbidity rate of around 10-15% of the population. However, the relationships between viral infections, host immune response, and host factors in the pathophysiology of asthma remain unclear. To gain a better understanding of the epidemiology of virus-induced asthma, it is important to assess both the characteristics of the viruses and the host defense mechanisms. Molecular epidemiology enables us to understand the pathogenesis of microorganisms by identifying specific pathways, molecules, and genes that influence the risk of developing a disease. However, the epidemiology of various respiratory viruses associated with virus-induced asthma is not fully understood. Therefore, in this article, we review molecular epidemiological studies of RSV, HRV, HPIV, and HMPV infection associated with virus-induced asthma.

Seasonality and prevalence of respiratory pathogens detected by multiplex PCR at a tertiary care medical center

Respiratory tract infections (RTIs) are a leading cause of mortality and morbidity. Seasonality has been reported for many viruses, including influenza virus, respiratory syncytial virus (RSV), and the recently described human metapneumovirus (hMPV). We hypothesize that the availability of rapid, multiplex PCR diagnostics will provide better clinical care and new insights into the etiology and clinical spectrum of RTIs. We conducted a retrospective analysis of the incidence of respiratory pathogens at a 500-bed adult and 154-bed pediatric hospital tertiary care center. A total of 939 specimens from patients with an age range of 5 days to 91 years (median, 2 years) were tested by a multiplex respiratory pathogen PCR from November 14, 2011 to November 13, 2012. Sixty-five percent of specimens were positive for at least one pathogen. As the age of the patient increased, the positivity rate for the PCR decreased proportionately. Rhinoviruses/enteroviruses (Rhino/Entero) were the most prevalent (34.3 %) followed by RSV (19.2 %) and hMPV (6.2 %). Twelve percent of the positive samples were positive for multiple analytes, with Rhino/Entero and RSV being the most common combination. The peak months were September and May for Rhino/Entero infections, January for RSV and February for coronavirus. hMPV peaked 2 months after RSV, as has been observed recently in other studies. Multiplex PCR provides rapid diagnostic information that can be used to make knowledgeable clinical decisions and potentially reduce the use of antibiotics. Active respiratory PCR surveillance could also predict seasonal respiratory epidemics to allow for adequate planning of additional infection control measures.

Respiratory virology and microbiology in intensive care units: a prospective cohort study

Our aim was to determine the frequency of 12 common respiratory viruses in patients admitted to intensive care units with respiratory symptoms, evaluate the clinical characteristics and to compare the results to routine microbiological diagnostics. Throat swabs from 122 intensive care-patients >18 years with acute respiratory symptoms were collected upon admission and analysed with multiplex real-time polymerase chain reaction, for 12 community respiratory viruses. Blood and respiratory tract specimens were analysed for bacteria and fungi upon clinicians' request. Clinical and paraclinical data were collected. Viruses were detected in 19 (16%) of the 122 study patients. Five virus-positive patients (26%) had possible clinically relevant bacteria or fungi co-detected. Patients with exacerbation in COPD were associated with a viral infection (p = 0.02). Other comorbidities, clinical and paraclinical parameters, and death were independent of a viral infection or co-detection of bacteria/fungi. In conclusion, respiratory viruses were frequently detected in the patients. The investigated clinical and paraclinical parameters were not different in viral infections compared to other agents, thus respiratory viruses likely have similar impact on the clinical course as other agents. In 25% of the virus-positive patients, polymicrobial aetiology was identified. Comprehensive and sensitive diagnostic methods should be emphasized to enhance respiratory diagnostics.

Eight years of the Great Influenza Survey to monitor influenza-like illness in Flanders

In 2003, an internet-based monitoring system of influenza-like illness (ILI), the Great Influenza Survey (GIS), was initiated in Belgium. For the Flemish part of Belgium, we investigate the representativeness of the GIS population and assess the validity of the survey in terms of ILI incidence during eight influenza seasons (from 2003 through 2011). The validity is investigated by comparing estimated ILI incidences from the GIS with recorded incidences from two other monitoring systems, (i) the Belgian Sentinel Network and (ii) the Google Flu Trends, and by performing a risk factor analysis to investigate whether the risks on acquiring ILI in the GIS population are comparable with results in the literature. A random walk model of first order is used to estimate ILI incidence trends based on the GIS. Good to excellent correspondence is observed between the estimated ILI trends in the GIS and the recorded trends in the Sentinel Network and the Google Flu Trends. The results of the risk factor analysis are in line with the literature. In conclusion, the GIS is a useful additional surveillance network for ILI monitoring in Flanders. The advantages are the speed at which information is available and the fact that data is gathered directly in the community at an individual level.