Respiratory viral infections in adults

Modeling respiratory tract diseases for clinical translation employing conditionally reprogrammed cells

Preclinical models serve as indispensable tools in translational medicine. Specifically, patient-derived models such as patient-derived xenografts (PDX), induced pluripotent stem cells (iPSC), organoids, and recently developed technique of conditional reprogramming (CR) have been employed to reflect the host characteristics of diseases. CR technology involves co-culturing epithelial cells with irradiated Swiss-3T3-J2 mouse fibroblasts (feeder cells) in the presence of a Rho kinase (ROCK) inhibitor, Y-27632. CR technique facilitates the rapid conversion of both normal and malignant cells into a "reprogrammed stem-like" state, marked by robust in vitro proliferation. This is achieved without reliance on exogenous gene expression or viral transfection, while maintaining the genetic profile of the parental cells. So far, CR technology has been used to study biology of diseases, targeted therapies (precision medicine), regenerative medicine, and noninvasive diagnosis and surveillance. Respiratory diseases, ranking as the third leading cause of global mortality, pose a significant burden to healthcare systems worldwide. Given the substantial mortality and morbidity rates of respiratory diseases, efficient and rapid preclinical models are imperative to accurately recapitulate the diverse spectrum of respiratory conditions. In this article, we discuss the applications and future potential of CR technology in modeling various respiratory tract diseases, including lung cancer, respiratory viral infections (such as influenza and Covid-19 and etc.), asthma, cystic fibrosis, respiratory papillomatosis, and upper aerodigestive track tumors. Furthermore, we discuss the potential utility of CR in personalized medicine, regenerative medicine, and clinical translation.

Surveillance of respiratory viruses by aerosol screening in indoor air as an early warning system for epidemics

The development of effective methods for the surveillance of seasonal respiratory viruses is required for the timely management of outbreaks. We aimed to survey Influenza-A, Influenza-B, RSV-A, Rhinovirus and SARS-CoV-2 surveillance in a tertiary hospital and a campus over 5 months. The effectiveness of air screening as an early warning system for respiratory viruses was evaluated in correlation with respiratory tract panel test results. The overall viral positivity was higher on the campus than in the hospital (55.0% vs. 38.0%). Influenza A was the most prevalent pathogen in both locations. There were two influenza peaks (42nd and 49th weeks) in the hospital air, and a delayed peak was detected on campus in the 1st-week of January. Panel tests indicated a high rate of Influenza A in late December. RSV-A-positivity was higher on the campus than the hospital (21.6% vs. 7.4%). Moreover, we detected two RSV-A peaks in the campus air (48th and 51st weeks) but only one peak in the hospital and panel tests (week 49). Although rhinovirus was the most common pathogen in panel tests, rhinovirus positivity was low in air samples. The air screening for Influenza-B and SARS-Cov-2 revealed comparable positivity rates with panel tests. Air screening can be integrated into surveillance programs to support infection control programs for potential epidemics of respiratory virus infections except for rhinoviruses.

Human Bronchial Epithelial Cell Transcriptome Changes in Response to Serum from Patients with Different Status of Inflammation

PURPOSE

To investigate the transcriptome of human bronchial epithelial cells (HBEC) in response to serum from patients with different degrees of inflammation.

METHODS

Serum from 19 COVID-19 patients obtained from the Hannover Unified Biobank was used. At the time of sampling, 5 patients had a WHO Clinical Progression Scale (WHO-CPS) score of 9 (severe illness). The remaining 14 patients had a WHO-CPS of below 9 (range 1-7), and lower illness. Multiplex immunoassay was used to assess serum inflammatory markers. The culture medium of HBEC was supplemented with 2% of the patient's serum, and the cells were cultured at 37 °C, 5% CO2 for 18 h. Subsequently, cellular RNA was used for RNA-Seq.

RESULTS

Patients with scores below 9 had significantly lower albumin and serum levels of E-selectin, IL-8, and MCP-1 than patients with scores of 9. Principal component analysis based on 500 "core genes" of RNA-seq segregated cells into two subsets: exposed to serum from 4 (I) and 15 (II) patients. Cells from a subset (I) treated with serum from 4 patients with a score of 9 showed 5566 differentially expressed genes of which 2793 were up- and 2773 downregulated in comparison with cells of subset II treated with serum from 14 patients with scores between 1 and 7 and one with score = 9. In subset I cells, a higher expression of TLR4 and CXCL8 but a lower CDH1, ACE2, and HMOX1, and greater effects on genes involved in metabolic regulation, cytoskeletal organization, and kinase activity pathways were observed.

CONCLUSION

This simple model could be useful to characterize patient serum and epithelial cell properties.

The EphA1 and EphA2 Signaling Modulates the Epithelial Permeability in Human Sinonasal Epithelial Cells and the Rhinovirus Infection Induces Epithelial Barrier Dysfunction via EphA2 Receptor Signaling

Deficiencies in epithelial barrier integrity are involved in the pathogenesis of chronic rhinosinusitis (CRS). This study aimed to investigate the role of ephrinA1/ephA2 signaling on sinonasal epithelial permeability and rhinovirus-induced epithelial permeability. This role in the process of epithelial permeability was evaluated by stimulating ephA2 with ephrinA1 and inactivating ephA2 with ephA2 siRNA or inhibitor in cells exposed to rhinovirus infection. EphrinA1 treatment increased epithelial permeability, which was associated with decreased expression of ZO-1, ZO-2, and occludin. These effects of ephrinA1 were attenuated by blocking the action of ephA2 with ephA2 siRNA or inhibitor. Furthermore, rhinovirus infection upregulated the expression levels of ephrinA1 and ephA2, increasing epithelial permeability, which was suppressed in ephA2-deficient cells. These results suggest a novel role of ephrinA1/ephA2 signaling in epithelial barrier integrity in the sinonasal epithelium, suggesting their participation in rhinovirus-induced epithelial dysfunction.

The burden of lower respiratory infections and their underlying etiologies in the Middle East and North Africa region, 1990-2019: results from the Global Burden of Disease Study 2019

BACKGROUND

Lower respiratory infections (LRIs) cause substantial mortality and morbidity. The present study reported and analysed the burden of LRIs in the Middle East and North Africa (MENA) region between 1990 and 2019, by age, sex, etiology, and socio-demographic index (SDI).

METHODS

The data used in this study were sourced from the Global Burden of Disease (GBD) study 2019. The annual incidence, deaths, and disability-adjusted life-years (DALYs) due to LRIs were presented as counts and age-standardised rates per 100,000 population, along with their 95% uncertainty intervals (UIs). The average annual percent changes (AAPC) in the age-standardised incidence, death and DALYs rates were calculated using Joinpoint software and correlations (Pearson's correlation coefficient) between the AAPCs and SDIs were calculated using Stata software.

RESULTS

In 2019, there were 34.1 million (95% UI 31.7-36.8) incident cases of LRIs in MENA, with an age-standardised rate of 6510.2 (95% UI 6063.6-6997.8) per 100,000 population. The number of regional DALYs was 4.7 million (95% UI 3.9-5.4), with an age-standardised rate of 888.5 (95% UI 761.1-1019.9) per 100,000 population, which has decreased since 1990. Furthermore, Egypt [8150.8 (95% UI 7535.8-8783.5)] and Afghanistan [61.9 (95% UI 52.1-72.6)] had the highest age-standardised incidence and death rates, respectively. In 2019, the regional incidence and DALY rates were highest in the 1-4 age group, in both females and males. In terms of deaths, pneumococcus and H. influenza type B were the most and least common types of LRIs, respectively. From 1990 to 2019, the burden of LRIs generally decreased with increasing SDI. There were significant positive correlations between SDI and the AAPCs for the age-standardised incidence, death and DALY rates (p < 0.05). Over the 1990-2019 period, the regional incidence, deaths and DALYs attributable to LRIs decreased with AAPCs of - 1.19% (- 1.25 to - 1.13), - 2.47% (- 2.65 to - 2.28) and - 4.21% (- 4.43 to - 3.99), respectively.

CONCLUSIONS

The LRI-associated burden in the MENA region decreased between 1990 and 2019. SDI had a significant positive correlation with the AAPC and pneumococcus was the most common underlying cause of LRIs. Afghanistan, Yemen and Egypt had the largest burdens in 2019. Further studies are needed to investigate the effectiveness of healthcare interventions and programs to control LRIs and their risk factors.

The Expression of ephrinA1/ephA2 Receptor Increases in Chronic Rhinosinusitis and ephrinA1/ephA2 Signaling Affects Rhinovirus-Induced Innate Immunity in Human Sinonasal Epithelial Cells

EphA2 receptor and its ephrin ligands are involved in virus infection, epithelial permeability, and chemokine secretion. We hypothesized that ephrinA1/ephA2 signaling participates in rhinovirus (RV)-induced antiviral immune response in sinonasal mucosa of patients with chronic rhinosinusitis (CRS). Therefore, we investigated the expression of ephrinA1/ephA2 in normal and inflamed sinonasal mucosa and evaluated whether they regulate chemokine secretion and the production of antiviral immune mediators including interferons (IFNs) in RV-infected human primary sinonasal epithelial cells. For this purpose, the expression and distribution of ephrinA1/ephA2 in sinonasal mucosa were evaluated with RT-qPCR, immunofluorescence, and western blot. Their roles in chemokine secretion and the production of antiviral immune mediators such as type I and III IFNs, and interferon stimulated genes were evaluated by stimulating ephA2 with ephrinA1 and inactivating ephA2 with ephA2 siRNA or inhibitor in cells exposed to RV and poly(I:C). We found that ephrinA1/ephA2 were expressed in normal mucosa and their levels increased in inflamed sinonasal mucosa of CRS patients. RV infection or poly(I:C) treatment induced chemokine secretion which were attenuated by blocking the action of ephA2 with ephA2 siRNA or inhibitor. The production of antiviral immune mediators enhanced by rhinovirus or poly (I:C) is increased by blocking ephA2 compared with that of cells stimulated by either rhinovirus or poly(I:C) alone. In addition, blocking ephA2 attenuated RV replication in cultured cells. Taken together, these results describe a novel role of ephrinA1/ephA2 signaling in antiviral innate immune response in sinonasal epithelium, suggesting their participation in RV-induced development and exacerbations of CRS.

POCT Detection of 14 Respiratory Viruses Using Multiplex RT-PCR

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

In Vitro Modelling of Respiratory Virus Infections in Human Airway Epithelial Cells - A Systematic Review

Respiratory tract infections (RTI) are a major cause of morbidity and mortality in humans. A large number of RTIs is caused by viruses, often resulting in more severe disease in infants, elderly and the immunocompromised. Upon viral infection, most individuals experience common cold-like symptoms associated with an upper RTI. However, in some cases a severe and sometimes life-threatening lower RTI may develop. Reproducible and scalable in vitro culture models that accurately reflect the human respiratory tract are needed to study interactions between respiratory viruses and the host, and to test novel therapeutic interventions. Multiple in vitro respiratory cell culture systems have been described, but the majority of these are based on immortalized cell lines. Although useful for studying certain aspects of viral infections, such monomorphic, unicellular systems fall short in creating an understanding of the processes that occur at an integrated tissue level. Novel in vitro models involving primary human airway epithelial cells and, more recently, human airway organoids, are now in use. In this review, we describe the evolution of in vitro cell culture systems and their characteristics in the context of viral RTIs, starting from advances after immortalized cell cultures to more recently developed organoid systems. Furthermore, we describe how these models are used in studying virus-host interactions, e.g. tropism and receptor studies as well as interactions with the innate immune system. Finally, we provide an outlook for future developments in this field, including co-factors that mimic the microenvironment in the respiratory tract.

Regulation of Lung Epithelial Sodium Channels by Cytokines and Chemokines

Acute lung injury leading to acute respiratory distress (ARDS) is a global health concern. ARDS patients have significant pulmonary inflammation leading to flooding of the pulmonary alveoli. This prevents normal gas exchange with consequent hypoxemia and causes mortality. A thin fluid layer in the alveoli is normal. The maintenance of this thin layer results from fluid movement out of the pulmonary capillaries into the alveolar interstitium driven by vascular hydrostatic pressure and then through alveolar tight junctions. This is then balanced by fluid reabsorption from the alveolar space mediated by transepithelial salt and water transport through alveolar cells. Reabsorption is a two-step process: first, sodium enters via sodium-permeable channels in the apical membranes of alveolar type 1 and 2 cells followed by active extrusion of sodium into the interstitium by the basolateral Na⁺, K⁺-ATPase. Anions follow the cationic charge gradient and water follows the salt-induced osmotic gradient. The proximate cause of alveolar flooding is the result of a failure to reabsorb sufficient salt and water or a failure of the tight junctions to prevent excessive movement of fluid from the interstitium to alveolar lumen. Cytokine- and chemokine-induced inflammation can have a particularly profound effect on lung sodium transport since they can alter both ion channel and barrier function. Cytokines and chemokines affect alveolar amiloride-sensitive epithelial sodium channels (ENaCs), which play a crucial role in sodium transport and fluid reabsorption in the lung. This review discusses the regulation of ENaC via local and systemic cytokines during inflammatory disease and the effect on lung fluid balance.

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.

Etiology of Influenza-Like Illnesses from Sentinel Network Practitioners in Réunion Island, 2011-2012

In Réunion Island, despite an influenza surveillance established since 1996 by the sentinel general practitioner’s network, little is known about the etiology of Influenza like-illness (ILI) that differs from influenza viruses in a tropical area. We set up a retrospective study using nasal swabs collected by sentinel GPs from ILI patients in 2011 and 2012. A total of 250 swabs were randomly selected and analyzed by multiplex reverse transcriptase polymerase chain reaction (RT-PCR) including research of 18 viruses and 4 bacteria. We detected respiratory viruses in 169/222 (76.1%) samples, mostly rhinovirus (23.4%), influenza A virus (21.2%), influenza B virus (12.6%), coronavirus (4.9%) and Human metapneumovirus (3.6%). Nine swabs (5.3% of positive swabs) revealed co-infections with two viruses identified, among which six concerned co-infections with influenza viruses. We observed important seasonal differences, with circulation of Human Metapneumoviruses, RSV A and B and coronavirus only during summer; whereas parainfluenza viruses were identified only during winter. In conclusion, this study highlights a substantial circulation of multiple respiratory pathogens in Réunion Island throughout the year. It shows that ILI are not only attributable to influenza and underlines the need for biological surveillance. As the use of multiplex RT-PCR showed its efficacy, it is now used routinely in the surveillance of ILI.

Virus-induced secondary bacterial infection: a concise review

Respiratory diseases are a very common source of morbidity and mortality among children. Health care providers often face a dilemma when encountering a febrile infant or child with respiratory tract infection. The reason expressed by many clinicians is the trouble to confirm whether the fever is caused by a virus or a bacterium. The aim of this review is to update the current evidence on the virus-induced bacterial infection. We present several clinical as well in vitro studies that support the correlation between virus and secondary bacterial infections. In addition, we discuss the pathophysiology and prevention modes of the virus–bacterium coexistence. A search of the PubMed and MEDLINE databases was carried out for published articles covering bacterial infections associated with respiratory viruses. This review should provide clinicians with a comprehensive idea of the range of bacterial and viral coinfections or secondary infections that could present with viral respiratory illness.

Human Rhinovirus-induced Proinflammatory Cytokine and Interferon-β Responses in Nasal Epithelial Cells From Chronic Rhinosinusitis Patients

Purpose

Asthma exacerbation from human rhinovirus (HRV) infection is associated with deficient antiviral interferon (IFN) secretion. Although chronic rhinosinusitis (CRS), an inflammatory upper airway disease, is closely linked to asthma, IFN-β responses to HRV infections in human nasal epithelial cells (HNECs) from CRS patients remain to be studied. We evaluated inflammatory and antiviral responses to HRV infection in HNECs from CRS patients.

Methods

HNECs, isolated from turbinate tissue of 13 patients with CRS and 14 non-CRS controls, were infected with HRV16 for 4 hours. The HRV titer, LDH activity, production of proinflammatory cytokines and IFN-β proteins, and expression levels of RIG-I and MDA5 mRNA were assessed at 8, 24, and 48 hours after HRV16 infection.

Results

The reduction in viral titer was slightly delayed in the CRS group compared to the non-CRS control group. IL-6 and IL-8 were significantly increased to a similar extent in both groups after HRV infection. In the control group, IFN-β production and MDA5 mRNA expression were significantly increased at 8 and 24 hours after HRV16 infection, respectively. By contrast, in the CRS group, IFN-β was not induced by HRV infection; however, HRV-induced MDA5 mRNA expression was increased, but the increase was slightly delayed compared to the non-CRS control group. The RIG-I mRNA level was not significantly increased by HRV16 infection in either group.

Conclusions

HRV-induced secretion of proinflammatory cytokines in CRS patients was not different from that in the non-CRS controls. However, reductions in viral titer, IFN-β secretion, and MDA5 mRNA expression in response to HRV infection in CRS patients were slightly impaired compared to those in the controls, suggesting that HRV clearance in CRS patients might be slightly deficient.

Molecular detection of respiratory viruses

Over the past several years a wide variety of molecular assays for the detection of respiratory viruses has reached the market. The tests described herein range from kits containing primers and probes detecting specific groups of viruses, to self-contained systems requiring specialized instruments that extract nucleic acids and perform the polymerase chain reaction with little operator input. Some of the tests target just the viruses involved in large yearly epidemics such as influenza, or specific groups of viruses such as the adenoviruses or parainfluenza viruses; others can detect most of the known respiratory viruses and some bacterial agents.

Epidemiological aspects of respiratory symptoms treated in the emergency room of a tertiary care hospital

OBJECTIVE:

To evaluate the prevalence of respiratory symptoms as the motive for emergency room visits by adult and pediatric patients, describing the major clinical syndromes diagnosed and the outcomes of the patients.

METHODS:

A cross-sectional study conducted in the emergency room of a tertiary care university hospital. Between November of 2008 and November of 2009, we reviewed the total number of emergency room visits per day. Children and adults who presented with at least one respiratory symptom were included in the study. The electronic medical records were reviewed, and the major characteristics of the patients were recorded.

RESULTS:

During the study period, there were 37,059 emergency room visits, of which 11,953 (32.3%) were motivated by respiratory symptoms. The prevalence of emergency room visits due to respiratory symptoms was 28.7% and 38.9% among adults and children, respectively. In adults, the rates of hospitalization and mortality were 21.2% and 2.7%, respectively, compared with 11.9% and 0.3%, respectively, in children. Among the adults, the time from symptom onset to emergency room visit correlated positively with the need for hospitalization (p < 0.0001), the length of the hospital stay (p < 0.0001), and the mortality rate (p = 0.028).

CONCLUSIONS:

We found a high prevalence of respiratory symptoms as the motive for emergency room visits by adult and pediatric patients. Our results could inform decisions regarding the planning of prevention measures. Further epidemiological studies are needed in order to clarify the risk factors for severe respiratory symptoms.

Survey of causative agents for acute respiratory infections among patients in Khartoum-State, Sudan, 2010-2011

BACKGROUND

This study was carried out to determine causative agents of acute respiratory illness of patients in Khartoum State, Sudan.

METHODS

Four hundred patients experiencing respiratory infections within January-March 2010 and January-March 2011 were admitted at Khartoum Hospital and had their throat swab samples subjected to multiplex real-time RT-PCR to detect influenza viruses (including subtypes) and other viral agents. Isolation, nucleotide sequence and phylogenetic analysis on some influenza viruses based on the HA gene were done.

RESULTS

Out of 400 patients, 66 were found to have influenza viruses (35, 27, 2, and 2 with types A, B, C, and A and B co-infections, respectively). Influenza viruses were detected in 28, 33 and 5 patients in the age groups <1, 1-10, and 11-30 years old, respectively but none in the 31-50 years old group. Out of 334 patients negative for influenza viruses, 27, 14, and 2 were positive for human respiratory syncytial virus, rhinovirus and adenovirus, respectively. Phylogenetic tree on influenza A (H1N1) pdm09 subtype shows that Sudan strains belong to the same clade and are related to those strains from several countries such as USA, Japan, Italy, United Kingdom, Germany, Russia, Greece, Denmark, Taiwan, Turkey and Kenya. Seasonal A H3 subtypes have close similarity to strains from Singapore, Brazil, Canada, Denmark, USA and Nicaragua. For influenza B, Sudan strains belong to two different clades, and just like influenza A (H1N1) pdm09 and A H3 subtypes, seem to be part of worldwide endemic population (Kenya, USA, Brazil, Russia, Taiwan and Singapore).

CONCLUSIONS

In Sudan, the existence of respiratory viruses in patients with acute respiratory infection was confirmed and characterized for the first time by using molecular techniques.

Prevalence of influenza and adherence to the anti-flu vaccination among elderly

INTRODUCTION: The flu, a condition that can affect the elderly by increasing the risk of serious complications can be prevented through vaccination. Estimate the prevalence of signs and symptoms suggestive of influenza in a group of elderly either vaccinated or unvaccinated against influenza was the objective this study. METHODS: This is a cross-sectional study performed in a Brazilian City. A structured questionnaire was employed to identify the presence of signs and symptoms of influenza in individuals aged 60 years or over. For analysis of associations between variables the prevalence ratio (PR) and its 95% confidence interval (95% CI) were used. RESULTS: One hundred ninety-six participants were interviewed, of whom 57.7% were female. The average age was 69.7 years. About 25% of the vaccinated and 20% of the unvaccinated in 2009, and 25% of the vaccinated and 22.5% of the unvaccinated in 2010 reported having the flu. Among the vaccinated and unvaccinated in 2009 and 2010, there was no verified association between vaccination and influenza (PR=1.24; [95% CI: 0.63-2.43] and PR=1.11; [95% CI: 0.59-2.09], respectively). CONCLUSIONS: This study suggests that, among the elderly selected, the vaccination coverage for influenza is below the ideal, even with projection of the best indices for 2011 (~ 84%). The data on vaccination and disease protection needs further research; however, the results point to the need for measures to better clarify to this population about the disease, its complications and the benefits of vaccination, in addition to combatting the stigma related to low adherence.

Effects of consumption of a fermented dairy product containing the probiotic Lactobacillus casei DN-114 001 on common respiratory and gastrointestinal infections in shift workers in a randomized controlled trial

OBJECTIVE

The risk of infection may be increased in people under stress such as shift workers. This study examined the effect of a fermented dairy product containing the probiotic Lactobacillus casei DN-114 001 (verum) on the incidence of respiratory and gastrointestinal common infectious diseases (CIDs) and on immune functions in healthy shift workers.

METHODS

The study was single-center, randomized, double-blind, and controlled. Volunteers received 200 g/day of verum (n = 500) or control product (n = 500) for 3 months; 1-month follow-up was carried out.

RESULTS

The cumulated number of CIDs (primary outcome) was not significantly different between groups. Because the Poisson distribution of the primary parameter did not fully fit the observed data, a post hoc categorical analysis was applied and showed a significantly lower cumulated number of CIDs in the verum group during the product consumption phase (odds ratio [OR] = 0.75, 95% confidence interval [CI] 0.59-0.95, p = 0.017). Verum also reduced the proportion of volunteers experiencing at least 1 CID (43% vs. 51%, p = 0.005), increased the time to the first occurrence of CID (p = 0.017) in the whole population, and reduced the cumulated number of CIDs in the subgroup of smokers (p = 0.033). In the course of CID, cumulated duration of fever was lower in the verum group (in the whole study phase) (p = 0.022), and an increase in leukocyte, neutrophil, and natural killer (NK) cell counts and activity (p = 0.047 to p < 0.001) was observed compared with control group. Verum was safe and well tolerated.

CONCLUSION

The results indicate that daily consumption of a fermented dairy product containing Lactobacillus casei DN-114 001 could reduce the risk of common infections in stressed individuals such as shift workers.

The airway epithelium: soldier in the fight against respiratory viruses

The airway epithelium acts as a frontline defense against respiratory viruses, not only as a physical barrier and through the mucociliary apparatus but also through its immunological functions. It initiates multiple innate and adaptive immune mechanisms which are crucial for efficient antiviral responses. The interaction between respiratory viruses and airway epithelial cells results in production of antiviral substances, including type I and III interferons, lactoferrin, β-defensins, and nitric oxide, and also in production of cytokines and chemokines, which recruit inflammatory cells and influence adaptive immunity. These defense mechanisms usually result in rapid virus clearance. However, respiratory viruses elaborate strategies to evade antiviral mechanisms and immune responses. They may disrupt epithelial integrity through cytotoxic effects, increasing paracellular permeability and damaging epithelial repair mechanisms. In addition, they can interfere with immune responses by blocking interferon pathways and by subverting protective inflammatory responses toward detrimental ones. Finally, by inducing overt mucus secretion and mucostasis and by paving the way for bacterial infections, they favor lung damage and further impair host antiviral mechanisms.

Laboratory diagnosis, epidemiology, and clinical outcomes of pandemic influenza A and community respiratory viral infections in southern Brazil

Community respiratory viruses (CRVs) are commonly associated with seasonal infections. They have been associated with higher morbidity and mortality among children, elderly individuals, and immunosuppressed patients. In April 2009, the circulation of a new influenza A virus (FLUA H1N1v) was responsible for the first influenza pandemic of this century. We report the clinical and epidemiological profiles of inpatients infected with CRVs or with FLUA H1N1v at a tertiary care hospital in southern Brazil. In addition, we used these profiles to evaluate survivor and nonsurvivor patients infected with FLUA H1N1v. Multiplex reverse transcription-PCR (RT-PCR) and real time RT-PCR were used to detect viruses in inpatients with respiratory infections. Record data from all patients were reviewed. A total of 171 patients were examined over a period of 16 weeks. Of these, 39% were positive for FLUA H1N1v, 36% were positive for CRVs, and 25% were negative. For the FLUA H1N1v- and CRV-infected patients, epidemiological data regarding median age (30 and 1.5 years), myalgia (44% and 13%), need for mechanical ventilation (44% and 9%), and mortality (35% and 9%) were statistically different. In a multivariate analysis comparing survivor and nonsurvivor patients infected with influenza A virus H1N1, median age and creatine phosphokinase levels were significantly associated with a severe outcome. Seasonal respiratory infections are a continuing concern. Our results highlight the importance of studies on the prevalence and severity of these infections and that investments in programs of clinical and laboratory monitoring are essential to detect the appearance of new infective agents.

Severe acute respiratory syndrome caused by the influenza A (H1N1) virus

In view of the pandemic caused by a new virus, influenza A (H1N1), we report the case of a 56-year-old patient without relevant risk factors and with severe acute respiratory syndrome resulting from infection with this virus. We present the results of laboratory tests and the imaging findings (chest X-ray and CT scans). The evolution was favorable, and the patient was discharged after 14 days.

Use of a fermented dairy probiotic drink containing Lactobacillus casei (DN-114 001) to decrease the rate of illness in kids: the DRINK study. A patient-oriented, double-blind, cluster-randomized, placebo-controlled, clinical trial

BACKGROUND

To evaluate whether a fermented dairy drink containing the probiotic strain Lactobacillus casei DN-114 001 could reduce the incidence of common infectious diseases (CIDs) and the change of behavior because of illness in children.

SUBJECTS/METHODS

We conducted a double-blinded, randomized, placebo-controlled allocation concealment clinical trial in the Washington, DC metropolitan area. Participants were 638 children 3-6 years old in daycare/schools. The intervention was a fermented dairy drink containing a specific probiotic strain or matching placebo with no live cultures for 90 consecutive days. Two primary outcomes were assessed: incidence of CIDs and change of behavior because of illness (both assessed by parental report).

RESULTS

The rate of change of behavior because of illness was similar among active and control groups. However, the incidence rate for CIDs in the active group (0.0782) is 19% lower than that of the control group (0.0986) (incidence rate ratio=0.81, 95% CI: 0.65, 099) P=0.046.

CONCLUSIONS

Daily intake of a fermented dairy drink containing the probiotic strain L. casei DN-114 001 showed some promise in reducing overall incidence of illness, but was primarily driven by gastrointestinal infections and there were no differences in change of behavior.

RespiFinder: a new multiparameter test to differentially identify fifteen respiratory viruses

Broad-spectrum analysis for pathogens in patients with respiratory tract infections is becoming more relevant as the number of potential infectious agents is still increasing. Here we describe the new multiparameter RespiFinder assay, which is based on the multiplex ligation-dependent probe amplification (MLPA) technology. This assay detects 15 respiratory viruses in one reaction. The MLPA reaction is preceded by a preamplification step which ensures the detection of both RNA and DNA viruses with the same specificity and sensitivity as individual monoplex real-time reverse transcription-PCRs. The RespiFinder assay was validated with 144 clinical samples, and the results of the assay were compared to those of cell culture and a respiratory syncytial virus (RSV)-specific immunochromatography assay (ICA). Compared to the cell culture results, the RespiFinder assay showed specificities and sensitivities of 98.2% and 100%, respectively, for adenovirus; 96.4% and 100%, respectively, for human metapneumovirus; 98.2% and 100%, respectively, for influenza A virus (InfA); 99.1% and 100%, respectively, for parainfluenza virus type 1 (PIV-1); 99.1% and 80%, respectively, for PIV-3; 90.1% and 100%, respectively, for rhinovirus; and 94.6% and 100%, respectively, for RSV. Compared to the results of the RSV-specific ICA, the RespiFinder assay gave a specificity and a sensitivity of 82.4% and 80%, respectively. PIV-2, PIV-4, influenza B virus, InfA H5N1, and coronavirus 229E were not detected in the clinical specimens tested. The use of the RespiFinder assay resulted in an increase in the diagnostic yield compared to that obtained by cell culture (diagnostic yields, 60% and 35.5%, respectively). In conclusion, the RespiFinder assay provides a user-friendly and high-throughput tool for the simultaneous detection of 15 respiratory viruses with excellent overall performance statistics.

Community acquired pneumonia in the tropics

PURPOSE OF REVIEW

Due to the exponential growth of international exchange, millions of travelers are exposed to respiratory pathogens in the tropics and may return ill. Community-acquired pneumonia is one of the more prevalent infections.

RECENT FINDINGS

The acquisition of infections in the tropics, including community-acquired pneumonias, has been described for several centuries. During recent decades some microorganisms have been disclosed as causative of the disease (Legionella pneumophila in 1976 and hantavirus in 1990); other microorganisms are real new pathogens that were not previously demonstrated to have a pathogenic role in humans (e.g. severe acute respiratory syndrome coronavirus producing an outbreak in 2003 and H5N1 avian influenza virus producing an increasing number of human cases over the last few years).

SUMMARY

A number of microorganisms may produce pneumonia in people who live or have traveled to tropical zones. History, including geography and epidemiology, physical exam and complementary workout are precious tools for the diagnosis, therapy and prevention. Exposure to microorganisms in tropical areas may show different patterns. A high index of suspicion, detailed investigation of travel, exposure history of the patient, and a basic understanding of the incubation periods and distribution of the various potential pathogens are imperative for the diagnosis.

What is the role of virus vaccination in patients with asthma?

It is estimated that viruses play a role in 30% to 80% of asthma exacerbations. Thus, virus vaccination in patients with asthma could play an important role in preventing asthma exacerbations and other complications. Influenza is the only agent for which a routine vaccine is currently available. This article discusses whether influenza vaccination in patients with asthma, based on the available evidence, is justified. Cost-effectiveness of (influenza) vaccination for patients with asthma is questionable. For the other major viruses involved, the present state of affairs is described. Although progress is being made, a vaccine may be available in the near future only for respiratory syncytial virus (RSV). Meanwhile, clinicians and patients should aim for an optimal treatment with the currently available asthma medication.

Simultaneous detection of five different DNA targets by real-time Taqman PCR using the Roche LightCycler480: Application in viral molecular diagnostics

One of the most interesting aspects of real-time PCR based on the detection of fluorophoric labeled oligonucleotides is the possibility of being able to detect conveniently multiple targets in the same PCR reaction. Recently, Roche Diagnostics launched a real-time PCR platform, the LightCycler480 (LC480), which should be well suited for multiplex real-time PCR analysis. In this paper the performance of the LC480 and accompanying software for the detection of five different targets was analyzed. Target DNAs mixed at equimolar concentrations were detected reproducibly and quantitatively. In addition, mixing different concentrations of the five targets demonstrated that the LC480 is capable of providing quantitative results for a mixture of DNA sequences without losing sensitivity. When applied to the practice of molecular diagnosis of four respiratory viral infections the multiplex assay showed almost complete concordance with corresponding single-target PCRs. The application of multiplex PCR for the detection of multiple pathogens within the same sample will provide a major contribution to the efficiency, logistics and cost-effectiveness of molecular diagnostics.

Lung epithelium as a sentinel and effector system in pneumonia--molecular mechanisms of pathogen recognition and signal transduction

Pneumonia, a common disease caused by a great diversity of infectious agents is responsible for enormous morbidity and mortality worldwide. The bronchial and lung epithelium comprises a large surface between host and environment and is attacked as a primary target during lung infection. Besides acting as a mechanical barrier, recent evidence suggests that the lung epithelium functions as an important sentinel system against pathogens. Equipped with transmembranous and cytosolic pathogen-sensing pattern recognition receptors the epithelium detects invading pathogens. A complex signalling results in epithelial cell activation, which essentially participates in initiation and orchestration of the subsequent innate and adaptive immune response. In this review we summarize recent progress in research focussing on molecular mechanisms of pathogen detection, host cell signal transduction, and subsequent activation of lung epithelial cells by pathogens and their virulence factors and point to open questions. The analysis of lung epithelial function in the host response in pneumonia may pave the way to the development of innovative highly needed therapeutics in pneumonia in addition to antibiotics.

Virus infection in exacerbations of chronic obstructive pulmonary disease requiring ventilation

Objectives

We aimed to characterise and quantify the incidence of common infectious agents in acute exacerbations of chronic obstructive pulmonary disease (COPD) requiring ventilation, with a focus on respiratory viruses.

Design

An epidemiological study conducted over 3 years.

Setting

A 12-bed intensive care unit (ICU).

Participants

ICU patients over 45 years of age with a primary diagnosis of COPD exacerbation requiring non-invasive ventilation (NIV) or ventilation via endotracheal tube (ETT).

Materials and methods

Nasopharyngeal aspirates (NPA) and posterior pharyngeal swabs (PS) were tested for viruses with immunofluorescence assay (IFA), virus culture (VC) and polymerase chain reaction (PCR). Paired virus and atypical pneumonia serology assays were taken. Blood, sputum and endotracheal aspirates were cultured for bacteria.

Results

107 episodes in 105 patients were recorded. Twenty-three (21%) died within 28 days. A probable infectious aetiology was found in 69 patient episodes (64%). A virus was identified in 46 cases (43%), being the sole organism in 35 cases (33%) and part of a mixed infection in 11 cases (10%). A probable bacterial aetiology was found in 25 cases (23%). There was no statistically significant difference in clinical characteristics or outcomes between the group with virus infections and that without.

Conclusion

Forty-six (43%) of the patients with COPD exacerbation requiring mechanical ventilation had a probable viral pathogen. Prodromal, clinical and outcome parameters did not distinguish virus from non-virus illness. PCR was the most sensitive whilst virus culture was the least of virus assays.

Electronic supplementary material

The electronic reference of this article is http://dx.doi.org/10.1007/s00134-006-0202-x. The online full-text version of this article includes electronic supplementary material. This material is available to authorised users and can be accessed by means of the ESM button beneath the abstract or in the structured full-text article. To cite or link to this article you can use the above reference.

Nosocomial viral ventilator-associated pneumonia in the intensive care unit: a prospective cohort study

OBJECTIVE

To determine the incidence, risk factors, and clinical relevance of viral ventilator-associated pneumonia (VAP) in an adult intensive care unit (ICU).

DESIGN

Prospective observational study.

SETTING

A 22-bed adult medical ICU in a university hospital.

PATIENTS

All consecutive adult patients ventilated more than 48 h in a 9-month period including regular seasonal viral infections.

INTERVENTIONS

A tracheobronchial aspirate upon enrollment and at the time of VAP suspicion.

MEASUREMENTS AND RESULTS

All respiratory specimens were tested in culture, indirect immunofluorescence assay, and PCR or RT-PCR for virological assessment. Patients were followed until ICU discharge or death. One hundred thirty-nine patients were included. Upon enrollment, a respiratory virus was detected in the tracheobronchial aspirate in 25% of patients (35 of 139). The incidence of VAP, defined according to clinical daily evaluation, was 28% (39 of 139 patients). A bacteria was documented in 74% of cases, whereas no case of a causative viral infection was encountered among VAP patients; however, herpes simplex virus type-1 (HSV 1) infection was detected in respiratory specimens of 31% of VAP (12 of 39).

CONCLUSIONS

We found a high incidence of HSV-1 infection in VAP patients; however, nosocomial viral VAP is likely to be rare in ICU, as assessed by the absence of respiratory virus-induced VAP identified in this prospective cohort study.

Viral respiratory infection in Curitiba, Southern Brazil

OBJECTIVE

Viral infection is the major cause of respiratory tract pathology affecting individuals of all ages, especially children and immunocompromised patients. There is a paucity of data on etiological and epidemiological infection caused by virus, in Southern Brazil. The aim of this study was to evaluate the seasonality, and the incidence of the viruses involved in respiratory infections in Curitiba, South Brazil.

METHODS

Two hundred seventy-three nasopharyngeal aspirates (NPA) from primary care health units and 1348 NPA or bronchoalveolar lavages from a tertiary-care teaching hospital were studied. Viruses were identified by indirect immunofluorescence and cellular culture.

RESULTS

Thirty percent of tested samples scored positive for the presence of virions. The percentages of infection for each virus from outpatients and hospitalized, respectively, were 3.3, 19.3 for respiratory syncytial virus; 13.9, 3.5 for influenza A, 3.0, 1.7 for influenza B; 3.3, 5.6 for parainfluenza virus and 2.2, 0.8 for adenovirus. A higher incidence of positive results was found during the winter season, thus showing a pattern of seasonality.

CONCLUSION

Viral agents are one of the main etiologies of respiratory tract pathology in the population studied.

Management of acute bronchitis in healthy adults

Acute respiratory infections (ARIs) are the most common infections in humans, accounting for half of all acute conditions each year in the United States. Acute bronchitis episodes represent a significant portion of these illnesses. This article focuses on acute bronchitis in otherwise healthy individuals.

Rapid and sensitive method using multiplex real-time PCR for diagnosis of infections by influenza a and influenza B viruses, respiratory syncytial virus, and parainfluenza viruses 1, 2, 3, and 4

Laboratory diagnosis of viral respiratory infections is generally performed by virus isolation in cell culture and immunofluorescent assays. Reverse transcriptase PCR is now recognized as a sensitive and specific alternative for detection of respiratory RNA viruses. A rapid real-time multiplex PCR assay was developed for the detection of influenza A and influenza B viruses, human respiratory syncytial virus (RSV), parainfluenza virus 1 (PIV1), PIV2, PIV3, and PIV4 in a two-tube multiplex reaction which used molecular beacons to discriminate the pathogens. A total of 358 respiratory samples taken over a 1-year period were analyzed by the multiplex assay. The incidence of respiratory viruses detected in these samples was 67 of 358 (19%) and 87 of 358 (24%) by culture and real-time PCR, respectively. Culture detected 3 influenza A virus, 2 influenza B virus, 57 RSV, 2 PIV1, and 2 PIV3 infections. All of these culture-positive samples and an additional 5 influenza A virus, 6 RSV, 2 PIV1, 1 PIV2, 1 PIV3, and 3 PIV4 infections were detected by the multiplex real-time PCR. The application of real-time PCR to clinical samples increases the sensitivity for respiratory viral diagnosis. In addition, results can be obtained within 6 h, which increases clinical relevance. Therefore, use of this real-time PCR assay would improve patient management and infection control.

Influenza virus inhibits ENaC and lung fluid clearance

Fluid-free alveolar space is critical for normal gas exchange. Influenza virus alters fluid transport across respiratory epithelia producing rhinorrhea, middle ear effusions, and alveolar flooding. However, the mechanism of fluid retention remains unclear. We investigated influenza virus strain A/PR/8/34, which can attach and enter mammalian cells but is incapable of viral replication and productive infection in mammalian epithelia, on epithelial sodium channels (ENaC) in rat alveolar type II (ATII) cells. In parallel, we determined the effects of virus on amiloride-sensitive (i.e., ENaC-mediated) fluid clearance in rat lungs in vivo. Although influenza virus did not change the inulin permeability of ATII monolayers, it rapidly reduced the net volume transport across monolayers. Virus reduced the open probability of single ENaC channels in apical cell-attached patches. U-73122, a phospholipase C (PLC) inhibitor, and PP2, a Src inhibitor, blocked the effect of virus on ENaC. GF-109203X, a protein kinase C (PKC) inhibitor, also blocked the effect, suggesting a PKC-mediated mechanism. In parallel, intratracheal administration of influenza virus produced a rapid inhibition of amiloride-sensitive (i.e., ENaC-dependent) lung fluid transport. Together, these results show that influenza virus rapidly inhibits ENaC in ATII cells via a PLC- and Src-mediated activation of PKC but does not increase epithelial permeability in this same rapid time course. We speculate that this rapid inhibition of ENaC and formation of edema when the virus first attaches to the alveolar epithelium might facilitate subsequent influenza infection and may exacerbate influenza-mediated alveolar flooding that can lead to acute respiratory failure and death.