Nasal and otologic effects of experimental respiratory syncytial virus infection in adults

Fluctuations in emergency department visits related to acute otitis media are associated with extreme meteorological conditions

Background

Climate change has been associated with a higher frequency of extreme weather events, resulting in an overall increase in morbidity and mortality. Acute otitis media (AOM) is one of the most common otolaryngological infections and accounts for 1.5% of emergency department visits. This study aimed to identify associations between extreme weather events and the immediate and delayed risks for AOM-related emergency department visits (EV).

Methods

A total of 1,465 AOM-related EVs were identified in the Vienna General Hospital between 2015 and 2018. A distributed lag non-linear model was applied to evaluate the relationship between extreme weather conditions and the total number of AOM-related EVs per day. The relative risk (RR) and cumulative RR (cRR) of single-day events and extended weather events over three days were analyzed over a lag period of 14 days.

Results

AOM-related EVs showed a pronounced seasonality, with the highest occurrence during winter. Single-day weather events affected AOM-related EVs only at high relative humidity. Prolonged extreme weather conditions over three days, however, significantly increased the cRR for AOM-related EVs to 3.15 [1.26-7.88; p = 0.014] and 2.14 [1.14-4.04; p = 0.018] at mean temperatures of -4°C (1^st-percentile - p₁) and 0°C (p₅) on the same day. Relative humidity of 37% (p₁) decreased RR to 0.94 [0.88-0.99; p = 0.032] on day 7, while extremely high humidity of 89% (p₉₉) led to an increased cRR of 1.43 [1.03-2.00; p = 0.034] on day 7. Heavy prolonged precipitation of 24mm (p₉₅) reduced cRR beginning day 4 up until day 14 to 0.52 [0.31-0.86; p = 0.012]. Prolonged low atmospheric pressure events of 985hPa (p₅) reduced the RR to 0.95 [0.91-1.00; p = 0.03], whereas extremely high atmospheric pressure events of 1013hPa (p₉₉) increased the RR to 1.11 [1.03-1.20; p = 0.008]. Extremely low wind speeds significantly diminished the RR of AOM-related EVs.

Conclusions

While single-day extreme weather events had little impact on the occurrence of AOM-related EVs, extended periods of extreme temperatures, relative humidity, precipitation, wind speeds and atmospheric pressure significantly impacted the RR for AOM-related EVs. These findings could help improve healthcare resource allocation in similar climates and aid in educating patients about the role of environmental factors in AOM.

Immunological and Inflammatory Biomarkers of Susceptibility and Severity in Adult Respiratory Syncytial Virus Infections

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in young infants. However, it is also a significant pathogen in older adults. Validated biomarkers of RSV disease severity would benefit diagnostics, treatment decisions, and prophylactic interventions. This review summarizes knowledge of biomarkers for RSV disease in adults.

METHODS

A literature review was performed using Ovid Medline, Embase, Global health, Scopus, and Web of Science for articles published 1946-October 2016. Nine articles were identified plus 9 from other sources.

RESULTS

From observational studies of natural infection and challenge studies in volunteers, biomarkers of RSV susceptibility or disease severity in adults were: (1) lower anti-RSV neutralizing antibodies, where neutralizing antibody (and local IgA) may be a correlate of susceptibility/severity; (2) RSV-specific CD8+ T cells in bronchoalveolar lavage fluid preinfection (subjects with higher levels had less severe illness); and (3) elevated interleukin-6 (IL-6), IL-8, and myeloperoxidase levels in the airway are indicative of severe infection.

CONCLUSIONS

Factors determining susceptibility to and severity of RSV disease in adults have not been well defined. Respiratory mucosal antibodies and CD8+ T cells appear to contribute to preventing infection and modulation of disease severity. Studies of RSV pathogenesis in at-risk populations are needed.

A viral-vectored RSV vaccine induces long-lived humoral immunity in cotton rats

Human respiratory syncytial virus (RSV) is the leading cause of lower airway disease in infants worldwide and repeatedly infects immunocompetent individuals throughout life. Severe lower airway RSV infection during infancy can be life-threatening, but is also associated with important sequelae including development of asthma and recurrent wheezing in later childhood. The basis for the inadequate, short-lived adaptive immune response to RSV infection is poorly understood, but it is widely recognized that RSV actively antagonizes Type I interferon (IFN) production. In addition to the induction of the anti-viral state, IFN production during viral infection is critical for downstream development of robust, long-lived immunity. Based on the hypothesis that a vaccine that induced robust IFN production would be protective, we previously constructed a Newcastle disease virus-vectored vaccine that expresses the F glycoprotein of RSV (NDV-F) and demonstrated that vaccinated mice had reduced lung viral loads and an enhanced IFN-γ response after RSV challenge. Here we show that vaccination also protected cotton rats from RSV challenge and induced long-lived neutralizing antibody production, even in RSV immune animals. Finally, pulmonary eosinophilia induced by RSV infection of unvaccinated cotton rats was prevented by vaccination. Overall, these data demonstrate enhanced protective immunity to RSV F when this protein is presented in the context of an abortive NDV infection.

Case study-based time-course analysis of symptoms of respiratory syncytial virus infections followed by acute sinusitis in otherwise-healthy adults

Reports on respiratory syncytial virus (RSV) infections are abundant in pediatric and geriatric populations but not many in healthy adults, and particularly, those which demonstrated the illness throughout its time course are rare. We report two otherwise-healthy adult cases, showing a number of evidence essential for confirmation of exclusive infections with RSV, and document their clinical features from the onset of the disease to recovery, including secondary sinusitis with magnetic resonance (MR) and computed tomography (CT) images. The infection was proven by isolating RSV belonging to subgroup B and by observing elevated anti-RSV antibody titer in the paired sera. Possible contribution of other pathogens including almost all respiratory viruses and representative bacteria, was excluded by negative results in multiplex PCR examination. In the first case, illness initiated with pharyngeal pain, followed by symptoms of sneezing, severe rhinorrhea and coughing, which peaked at approximately 5-7 days and persisted for 12 days. The patient experienced a slight chill, but the body temperature did not exceed 37 °C during illness. The patient showed no significant finding but only a slight increase in serum C-reactive protein level in the routine clinical laboratory examinations. On the 9th day of illness, a dull headache started persisting for at least a week after which it gradually waned. Sinusitis was found by chance on MR images of maxillary sinus 8 days after the headache started, and the finding disappeared on CT images taken after 6 months. In the second case, the symptoms included severe rhinorrhea and dull facial pain around the upper nose; the pain also occurred on the 9th day of illness and the symptom was clinically diagnosed to be acute sinusitis during a visit to a physician.

Respiratory Syncytial Virus: Infection, Detection, and New Options for Prevention and Treatment

Respiratory syncytial virus (RSV) infection is a significant cause of hospitalization of children in North America and one of the leading causes of death of infants less than 1 year of age worldwide, second only to malaria. Despite its global impact on human health, there are relatively few therapeutic options available to prevent or treat RSV infection. Paradoxically, there is a very large volume of information that is constantly being refined on RSV replication, the mechanisms of RSV-induced pathology, and community transmission. Compounding the burden of acute RSV infections is the exacerbation of preexisting chronic airway diseases and the chronic sequelae of RSV infection. A mechanistic link is even starting to emerge between asthma and those who suffer severe RSV infection early in childhood. In this article, we discuss developments in the understanding of RSV replication, pathogenesis, diagnostics, and therapeutics. We attempt to reconcile the large body of information on RSV and why after many clinical trials there is still no efficacious RSV vaccine and few therapeutics.

Dose-response models for selected respiratory infectious agents: Bordetella pertussis, group a Streptococcus, rhinovirus and respiratory syncytial virus

BACKGROUND

Dose-response assessment is one step in quantitative microbial risk assessment (QMRA). Four infectious microbes capable of causing respiratory diseases important to public health, and for which dose-response functions have not been available are: Bordetella pertussis (whooping cough), group A Streptococcus (pharyngitis), rhinovirus (common cold) and respiratory syncytial virus (common cold). The objective of this study was to fit dose-response functions for these microbes to published experimental data.

METHODS

Experimental infectivity data in human subjects and/or animal models were identified from the peer-reviewed literature. The exponential and beta-Poisson dose-response functions were fitted using the method of maximum likelihood, and models compared by Akaike's Information Criterion.

RESULTS

Dose-response functions were identified for each appropriate data set for the four infectious microbes. Statistical and graphical measures of fit are presented.

CONCLUSIONS

With the fitted dose-response functions it will be possible to perform QMRA for these microbes. The dose-response functions, however, have a number of limitations associated with the route of exposure, use of animal hosts, and quality of fit. As a result, thoughtfulness must be used in selecting one dose-response function for a QMRA, and the function should be recognized as a significant source of uncertainty. Nonetheless, QMRA offers a transparent, systematic framework within which to understand the mechanisms of disease transmission, and evaluate interventions.

Eustachian tube opening measured by sonotubometry is poorer in adults with a history of past middle ear disease

OBJECTIVE

Test the hypothesis that active Eustachian tube opening efficiency as measured by sonotubometry is higher in adults with no extant middle-ear disease and no history of previous otitis media (Group-1) when compared to adults with no middle-ear disease but a positive history for otitis media (Group-2).

METHODS

Eustachian tube function for 1 ear of 33 otherwise healthy adult subjects, 16 assigned to Group-1 and 17 to Group-2, was tested by sonotubometry using a standard protocol. For each test, the sound envelopes for 3 swallows were abstracted independently by 2 observers from the data stream and 7 descriptive parameters related to sound envelope "shape" were calculated. Inter-relatedness among the values for the parameters was explored using correlation analysis. The contributions of swallow, observer and group to the variance in each parameter were evaluated for significance using a General Linear Model.

RESULTS

The shape parameters reflecting envelope height, area and rise and fall rates were highly inter-correlated, but those reflecting envelope widths were not. There was no effect of "swallow" on any of the parameters; but there was a significant "observer" effect on all measures of envelope width, greater for observer-2, and a significant "group" effect for 5 of the 7 shape parameters, all greater in Group-1.

CONCLUSIONS

Quantifiable measures of the sound signal "shape" recorded by sonotubometry during swallowing were significantly different between the 2 groups of subjects. This is interpretable as evidencing a more efficient Eustachian tube opening-function in adults with healthy middle ears who do not have a previous history of otitis media when compared to similar adults with a history of prior otitis media. Inefficient Eustachian tube function as children may not be completely resolved by adulthood increasing adult otitis media risk when Eustachian tube function is down-graded by extant upper respiratory diseases that provoke nasopharyngeal inflammation.

High detection rates of nucleic acids of a wide range of respiratory viruses in the nasopharynx and the middle ear of children with a history of recurrent acute otitis media

Both bacteria and viruses play a role in the development of acute otitis media, however, the importance of specific viruses is unclear. In this study molecular methods were used to determine the presence of nucleic acids of human rhinoviruses (HRV; types A, B, and C), respiratory syncytial viruses (RSV; types A and B), bocavirus (HBoV), adenovirus, enterovirus, coronaviruses (229E, HKU1, NL63, and OC43), influenza viruses (types A, B, and C), parainfluenza viruses (types 1, 2, 3, 4A, and 4B), human metapneumovirus, and polyomaviruses (KI and WU) in the nasopharynx of children between 6 and 36 months of age either with (n = 180) or without (n = 66) a history of recurrent acute otitis media and in 238 middle ear effusion samples collected from 143 children with recurrent acute otitis media. The co‐detection of these viruses with Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis was analyzed. HRV (58.3% vs. 42.4%), HBoV (52.2% vs. 19.7%), polyomaviruses (36.1% vs. 15.2%), parainfluenza viruses (29.4% vs. 9.1%), adenovirus (25.0% vs. 6.1%), and RSV (27.8% vs. 9.1%) were detected significantly more often in the nasopharynx of children with a history of recurrent acute otitis media compared to healthy children. HRV was predominant in the middle ear and detected in middle ear effusion of 46% of children. Since respiratory viruses were detected frequently in the nasopharynx of both children with and without a history of recurrent acute otitis media, the etiological role of specific viruses in recurrent acute otitis media remains uncertain, however, anti‐viral therapies may be beneficial in future treatment and prevention strategies for acute otitis media. J. Med. Virol. 83:2008–2017, 2011. © 2011 Wiley‐Liss, Inc.

Minimum Infective Dose of the Major Human Respiratory and Enteric Viruses Transmitted Through Food and the Environment

Viruses are a significant cause of morbidity and mortality around the world. Determining the minimum dose of virus particles that can initiate infection, termed the minimum infective dose (MID), is important for the development of risk assessment models in the fields of food and water treatment and the implementation of appropriate infection control strategies in healthcare settings. Both respiratory and enteric viruses can be shed at high titers from infected individuals even when the infection is asymptomatic. Presence of pre-existing antibodies has been shown to affect the infectious dose and to be protective against reinfection for many, but not all viruses. Most respiratory viruses appear to be as infective in humans as in tissue culture. Doses of <1 TCID50 of influenza virus, rhinovirus, and adenovirus were reported to infect 50% of the tested population. Similarly, low doses of the enteric viruses, norovirus, rotavirus, echovirus, poliovirus, and hepatitis A virus, caused infection in at least some of the volunteers tested. A number of factors may influence viruses' infectivity in experimentally infected human volunteers. These include host and pathogen factors as well as the experimental methodology. As a result, the reported infective doses of human viruses have to be interpreted with caution.

Upper respiratory virus detection without parent-reported illness in children is virus-specific

Background

Viral upper respiratory tract infection (vURI) may or may not present with a cold/flu-like illness (CFLI).

Objectives

For common upper respiratory viruses that cause vURIs, to determine the relative frequencies of virus detection by PCR in subjects with and without CFLIs.

Study design

Prospective follow-up of 170 children aged 1–8.6 years through the CFLI season by daily parental diary for CFLI episodes and nasal secretion sampling using PCR assays for adenovirus, coronavirus (types 229E and OC43), influenza virus (types A and B), parainfluenza (types 1–3) virus, rhinovirus, and respiratory syncytial virus (RSV).

Results

Virus was detected in 415 of 956 independent assays: 425 CFLI episodes and 531 non-CFLI periods were sampled; samples from 270 (64%) CFLI episodes and 145 (27%) non-CFLI periods contained virus detected by PCR. Rhinovirus was most frequently detected at 64%, followed by mixed viruses at 12%, RSV at 7%, and the other viruses at 3–5% of all detections. About 85% of RSV, influenza A and adenovirus detections were associated with a CFLI, whereas less than 62% of other virus detections were associated with CFLI.

Conclusions

The frequency of PCR virus detection without CFLI was different among viruses. This introduces virus-specific biases to estimating the frequencies of specific complications attributable to a vURI when ascertained by CFLI identification.

Temporal relationships between colds, upper respiratory viruses detected by polymerase chain reaction, and otitis media in young children followed through a typical cold season

INTRODUCTION

Otitis media is a frequent complication of a viral upper respiratory tract infection, and the reported co-incidence of those diseases increases with assay sensitivity and sampling density. We determined the incidence of otitis-media complications in young children when referenced to cold-like illnesses and to concurrent virus recovery from the nasopharynx.

METHODS

A total of 60 children from 24 families were followed from October 2003 through April 30, 2004, by daily parental recording of illness signs, weekly pneumatic otoscopic examinations, and periodic polymerase chain reaction assay of collected nasal fluids for common viruses.

RESULTS

One hundred ninety-nine cold-like illnesses were observed, but a sample for virus assay was not collected concurrent with 71 episodes. Of the remainder, 73% of cold-like illnesses were temporally related to recovery of 1 or a combination of the assayed viruses, with rhinovirus predominating. For non-cold-like illness periods, 54 (18%) of 297 assays were positive for virus, and the virus frequency distribution was similar to that for cold-like illnesses. There were 93 diagnosed otitis-media episodes; 65 (70%) of these occurred during a cold-like illness. For the 79 otitis-media episodes with available nasal samples, 61 (77%) were associated with a positive virus result. In this population, the otitis-media complication rate for a cold-like illness was 33%.

CONCLUSIONS

A cold-like illness was not a prerequisite for polymerase chain reaction detection of viruses in the nose and nasopharynx of young children. Viral detection by polymerase chain reaction in the absence of a cold-like illness is associated with complications in some subjects. Otitis media is a complication of viral infection both with and without concurrent cold-like illnesses, thus downwardly biasing coincidence estimates that use cold-based illnesses as the denominator.

Use of diagnostic algorithms and new technologies to study the incidence and prevalence of viral upper respiratory tract infections and their complications in high risk populations

PURPOSE OF REVIEW

Most studies on the natural history of viral upper respiratory tract infections and their complications rely for ascertainment on self-assessed cold/flu illness or the identification of presumed complications. The criteria for cold/flu definition, however, are variable within and between individuals and illness is not prerequisite for a viral upper respiratory tract infection. These factors bias estimates of the incidence and prevalence of viral upper respiratory tract infections and their complications. Here we review new methodologies that can be adapted for use in future studies to refine those estimates.

RECENT FINDINGS

We present a theoretical basis for standardized assignment of cold/flu episodes using a minimal algorithm template that operates on a structured set of symptoms/signs. We emphasize the greater accuracy of information derived from longitudinal studies that incorporate identification algorithms and assay of nasal secretions for causal virus by polymerase chain reaction and for proinflammatory chemicals to confirm nasal inflammation.

SUMMARY

The methodologies and sampling strategies that we describe hold promise for better characterizing the incidence of complications for symptomatic and asymptomatic expressions of a viral upper respiratory tract infection caused by specific viruses. These data can then be used to estimate the efficacy and efficiency in a specified target population of prophylactic or intercurrent treatments to prevent the complications.

Allergy skin test responses during experimental infection with respiratory syncytial virus

BACKGROUND

Allergy skin testing is one of the most frequently performed physician office procedures. Many factors can affect the results of those tests, including the well-defined suppressive effect of systemic antihistamines. False-positive allergen skin test results are known to occur; however, contributing factors are not well understood.

OBJECTIVE

To determine whether a viral upper respiratory tract infection affects allergy skin test responsiveness.

METHODS

We performed skin tests with histamine and a panel of geographically relevant inhalant allergens on 16 adults before and 3, 6, and 21 days after experimental exposure to respiratory syncytial virus (RSV), a virus that causes signs and symptoms of a cold.

RESULTS

The RSV exposure, with and without documented infection, caused increased wheal and flare areas to histamine and allergen and de novo positive allergen test responses in individuals with no measurable responses at baseline. These were noted as late as 21 days after RSV exposure and may be consistent with mediation by up-regulated neurogenic inflammation during RSV infection.

CONCLUSION

These results may have implications for explaining the cause of such well-known complications of RSV infection as otitis media, bronchiolitis, and asthmatic exacerbation.

Cytokine amplification by respiratory syncytial virus infection in human nasal epithelial cells

OBJECTIVES

Respiratory syncytial virus (RSV) is an important cause of upper respiratory infections and is known to play a causal role in the pathogenesis of rhinitis, sinusitis, acute otitis media, and pneumonia. RSV appears to prime the respiratory tract to secondary inciting events, such as bacterial or antigen challenges. To study the proinflammatory priming effects of RSV infection, cytokine expression was measured in well-differentiated human nasal epithelial cells (WD-NE) after RSV infection alone or after subsequent tumor necrosis factor (TNF)-alpha stimulation.

STUDY DESIGN

In vitro investigation.

METHODS

Human nasal epithelial cells were obtained from surgical specimens and allowed to differentiate in air-liquid interface cultures until ciliation and mucus production were evident. Two experimental paradigms were used. First, accumulation of cytokines in the media was measured by real-time, quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay after RSV infection alone. In the second set of experiments, cytokines were also measured after TNF-alpha stimulation in both RSV-infected and uninfected cultures.

RESULTS

RSV infection of WD-NE resulted in significant accumulations of interleukin (IL)-6, IL-8, and RANTES when compared with findings in control samples. Real-time, quantitative RT-PCR demonstrated significant increases in IL-8 gene expression following RSV infection when compared to controls. Secondary TNF-alpha stimulation following well-established (i.e., 72 h) RSV infection induced marked increases in IL-6, IL-8, and RANTES when compared with both RSV infection alone and TNF-alpha stimulation alone.

CONCLUSIONS

These findings suggest that RSV infection primes nasal epithelial cells to secondary proinflammatory challenge, resulting in a hyperimmune response. RSV-induced priming of a hyperimmune response may be important in the pathogenesis of sinusitis, acute otitis media, and pneumonia.

Studies in otitis media: Children's Hospital of Pittsburgh-University of Pittsburgh progress report--2004

OBJECTIVES/HYPOTHESIS

The present Progress Report has summarized the key otitis media clinical trials and laboratory studies conducted since 1969 by investigators at the Children's Hospital of Pittsburgh-University of Pittsburgh (Pittsburgh, PA).

STUDY DESIGN

Review.

METHODS

Included in the discussion are the following: 1) studies of the epidemiology and risk factors; 2) anatomy and pathology of the eustachian tube-middle ear from human temporal bone histopathological specimens; 3) physiology and pathophysiology of the eustachian tube-middle ear in humans and animal models; 4) pathogenesis; 5) otitis media in special populations (e.g., patients with cleft palate, Native Americans, patients with Down syndrome); 6) microbiology; 7) diagnosis; 8) outcomes of randomized clinical trials that evaluated efficacy of nonsurgical and surgical methods of treatment and prevention; 9) studies of certain complications and sequelae (e.g., effect of middle-ear effusion on hearing, early child development, and the vestibular system; chronic suppurative otitis media). Also included are relevant summary tables and 256 references.

Cytokine levels during symptomatic viral upper respiratory tract infection

BACKGROUND

Previous studies suggest a role for locally produced proinflammatory cytokines in the development and expression of illness during experimental infection with a variety of respiratory viruses. However, most of these studies fail to make comparisons between symptomatic and asymptomatic infected subjects.

OBJECTIVE

To compare the pattern of nasal cytokine elaboration in asymptomatic and symptomatic subjects experimentally infected with rhinovirus-39 (RV-39).

METHODS

Healthy adults underwent experimental intranasal inoculation with a safety-tested clinical isolate of RV-39. Nasal lavages were collected, nasal symptoms were recorded, and expelled nasal secretions were weighed before and then daily for 6 days after challenge. Nasal lavages were submitted for viral culture and assayed for cytokine protein levels by enzyme-linked immunosorbent assay.

RESULTS

Twenty-nine subjects were enrolled in the study. All subjects were infected as evidenced by viral shedding and/or seroconversion. Sixteen subjects were symptomatic and 13 were asymptomatic as evaluated by subject self-report. During infection, significant increases in mean levels of nasal interleukin 6 (IL-6) (P = .01) and IL-1 (P = .02) were observed in symptomatic but not asymptomatic subjects. In symptomatic subjects, these increases were temporally related to the development of nasal symptoms and production of secretions. Mean levels of IL-8, IL-10, and tumor necrosis factor a were not increased in either group during infection.

CONCLUSIONS

The results of this study demonstrate elevations in certain locally produced cytokines during symptomatic but not asymptomatic respiratory infection with RV-39. Future studies using selected anticytokine therapies may help elucidate the precise role of cytokines in mediating disease expression.

Prevention of otitis media caused by viral upper respiratory tract infection: vaccines, antivirals, and other approaches

Otitis media (OM) imposes significant morbidity on the pediatric age group and a large financial burden on the general population. Because standard medical treatments are not highly efficacious in resolving the accompanying middle ear (ME) inflammation, a goal of current research is OM prevention. Past studies show that new episodes of OM are usually a complication of viral upper respiratory infection (vURI), and therefore, a rational approach to achieving that goal is to develop intervention strategies that target vURI-associated OM. However, past experiences with antibiotics show that, in the absence of well-defined treatment protocols that maximize expected efficacy, the adoption of prophylactic or active treatments for OM can have negative consequences for the patient and for the general population. In this review, we discuss the hypothesized mechanisms by which a vURI is translated into an acute OM episode and describe different strategies for aborting that process. Limitations to deployment of each strategy are outlined.

Importance of respiratory viruses in acute otitis media

Acute otitis media is usually considered a simple bacterial infection that is treated with antibiotics. However, ample evidence derived from studies ranging from animal experiments to extensive clinical trials supports a crucial role for respiratory viruses in the etiology and pathogenesis of acute otitis media. Viral infection of the upper respiratory mucosa initiates the whole cascade of events that finally leads to the development of acute otitis media as a complication. The pathogenesis of acute otitis media involves a complex interplay between viruses, bacteria, and the host's inflammatory response. In a substantial number of children, viruses can be found in the middle-ear fluid either alone or together with bacteria, and recent studies indicate that at least some viruses actively invade the middle ear. Viruses appear to enhance the inflammatory process in the middle ear, and they may significantly impair the resolution of otitis media. Prevention of the predisposing viral infection by vaccination against the major viruses would probably be the most effective way to prevent acute otitis media. Alternatively, early treatment of the viral infection with specific antiviral agents would also be effective in reducing the occurrence of acute otitis media.

Cytokine gene polymorphisms moderate responses to respiratory syncytial virus in adults

Immune responses and illness severity during viral upper respiratory infections may be influenced by the local elaboration of cytokines. Cytokine gene polymorphisms moderate immune responses and severity of illness in various inflammatory and infectious diseases. We performed cytokine genotyping on 29 adults experimentally inoculated with respiratory syncytial virus (RSV) to determine whether specific cytokine gene polymorphisms are associated with immune responses or illness severity. DNA was extracted from leukocytes and assayed for TNF-alpha, IFN-gamma, IL-6, IL-10 and TGF-beta1 genotypes using polymerase chain reaction-sequence-specific primer technology. Outcomes consisted of baseline and convalescent RSV-specific serum IgG and nasal IgA titers, nasal secretion weights, nasal, throat and general symptom scores, and nasal cytokine protein levels. IFN-gamma genotype was directly related with the frequency of subjects having at least a four-fold increase in RSV-specific serum IgG and TNF-alpha genotype was inversely associated with the frequency of subjects having at least a twofold increase in RSV-specific nasal IgA. Additionally, IL-6 genotype was predictive of certain measures of illness expression, while IFN-gamma genotype predicted IL-1 protein levels, and TNF-alpha genotype predicted IL-6 and IL-8 protein levels in nasal lavage fluids. There were no associations between IL-10 or TGF-beta1 and any of the outcome parameters. These results suggest that certain cytokine gene polymorphisms moderate immune responses and illness severity in adults experimentally exposed to RSV.

Viral otitis media

Acute otitis media (AOM) and viral upper respiratory tract infections (URIs) represent the two most common diseases affecting the human population, and account for substantial patient morbidity and health care costs. Epidemiologic and experimental studies suggest that URIs play a causal role in the pathogenesis of AOM. Specifically, viruses can either invade the middle ear (ME) space and invoke an inflammatory response that culminates in ME effusion formation and consequent symptoms, or URIs might cause eustachian-tube dysfunction, resulting in negative ME pressures and subsequent ME effusion (hydrops ex vacuo theory). The events responsible for the inflammatory response of the human ME following viral exposure have not been well characterized. Although many prophylactic and therapeutic interventions have been evaluated for the treatment of AOM, the information on virus-specific interventions is sparse. In this article, the epidemiology, pathogenesis, diagnosis, and management of viral otitis media are reviewed.