scholarly journals Temperature Dependent Viral Tropism (TDVT): Understanding Viral Seasonality and Pathogenicity as Applied to the Avoidance and Treatment of Endemic Viral Respiratory Illnesses

2021 ◽  
Author(s):  
Patrick D. Shaw Stewart ◽  
Julia Bach
Keyword(s):  
Thermal Sensitivity ◽  
Respiratory Illness ◽  
Respiratory Viruses ◽  
Upper Respiratory Tract ◽  
Temperature Dependent ◽  
Viral Tropism ◽  
Local Climate ◽  
Respiratory Illnesses ◽  
The Tropics ◽  
Viral Respiratory

This review seeks to explain four features of viral respiratory illnesses that have perplexed generations of virologists: (1) the seasonal timing of respiratory illness; (2) the common viruses causing respiratory illness worldwide, including year-round disease in the Tropics; (3) the rapid response of outbreaks to weather, specifically temperature; (4) the rapid arrival and termination of epidemics caused by influenza and other viruses. The inadequacy of the popular explanations of seasonality is discussed, and a simple hypothesis is proposed, called Temperature Dependent Viral Tropism (TDVT), that is compatible with the above features of respiratory illness. TDVT notes that viruses can transmit themselves more effectively if they moderate their pathogenicity (thereby maintaining host mobility) and suggests that endemic respiratory viruses accomplish this by developing thermal sensitivity within a range that supports organ-specific viral tropism within the human body, whereby they replicate most rapidly at temperatures below body temperature. This allows them to confine themselves to the upper respiratory tract and to avoid infecting the lungs, heart, gut etc. Biochemical and tissue-culture studies show that “wild” respiratory viruses show such natural thermal sensitivity. The typical early autumn surge of colds and the existence of respiratory illness in the Tropics year-round at intermediate levels are explained by the tendency for strains to adapt their thermal sensitivity to their local climate and season. The TDVT hypothesis has important practical implications for preventing and treating respiratory illness including Covid-19. TVDT is testable with many options for experiments to increase our understanding of viral seasonality and pathogenicity.

scholarly journals Temperature Dependent Viral Tropism: An Explanation of the Seasonality and Pathogenicity of the Endemic Respiratory Viruses

2021 ◽  
Author(s):  
Patrick Shaw Stewart
Keyword(s):  
Thermal Sensitivity ◽  
Respiratory Illness ◽  
Respiratory Viruses ◽  
Upper Respiratory Tract ◽  
Temperature Dependent ◽  
Viral Tropism ◽  
Local Climate ◽  
Respiratory Illnesses ◽  
Organ Specific ◽  
Viral Respiratory

This review seeks to explain four features of viral respiratory illnesses that have perplexed many generations of microbiologists: (1) the seasonal occurrence of viral respiratory illness; (2) the occurrence of respiratory illness year-round in the Tropics; (3) the rapid response of illness to temperature drops in temperate regions; (4) the explosive arrival and rapid termination of epidemics caused by influenza and other respiratory viruses. I discuss the inadequacy of the popular explanations of seasonality, and propose a simple hypothesis, called Temperature Dependent Viral Tropism (TD-VT), that is compatible with the above and other features of respiratory illness. TD-VT notes that viruses can often transmit themselves more effectively if they moderate their pathogenicity (thereby maintaining the mobility of their hosts) and suggests that most endemic respiratory viruses accomplish this by developing thermal sensitivity, in the sense that they normally replicate rapidly only at temperatures below normal body temperature. This allows them to confine themselves to the upper respiratory tract and to avoid infecting the lungs, heart, gut etc. I review biochemical and tissue-culture studies that found that “wild” respiratory viruses often show natural thermal sensitivity within a range that supports organ-specific tropism within the human body, and I discuss the evident tendency for viral strains to adapt their thermal sensitivity to their local climate and season. I also explore the possible misinterpretation of early experiments where volunteers were inoculated nasally with viral samples and then chilled. Next, I discuss the practical implications of the TD-VT hypothesis for preventing and treating respiratory illness. Finally, I note that the hypothesis is very testable and make suggestions for the most important experiments to increase our understanding of the seasonality and pathogenicity of viral respiratory illness.

scholarly journals Psychosocial Vulnerabilities to Upper Respiratory Infectious Illness: Implications for Susceptibility to Coronavirus Disease 2019 (COVID-19)

2020 ◽  
pp. 174569162094251 ◽  
Author(s):  
Sheldon Cohen
Keyword(s):  
Psychosocial Factors ◽  
Alcohol Intake ◽  
Respiratory Illness ◽  
Respiratory Viruses ◽  
Upper Respiratory Tract ◽  
Respiratory Illnesses ◽  
Virus Exposure ◽  
Upper Respiratory ◽  
Infectious Illness ◽  
Moderate Alcohol Intake

For 35 years, our laboratory has been involved in identifying psychosocial factors that predict who becomes ill when they are exposed to a virus affecting the upper respiratory tract. To pursue this question, we used a unique viral-challenge design in which we assessed behavioral, social, and psychological factors in healthy adults. We subsequently exposed these adults to a cold or influenza virus and then monitored them in quarantine for 5 to 6 days for onset of respiratory illness. Factors we found to be associated with greater risk of respiratory illnesses after virus exposure included smoking, ingesting an inadequate level of vitamin C, and chronic psychological stress. Those associated with decreased risk included social integration, social support, physical activity, adequate and efficient sleep, and moderate alcohol intake. We cautiously suggest that our findings could have implications for identifying who becomes ill when exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19). This argument is based on evidence that the associations we report are replicable across multiple respiratory viruses and that the pathways found to link psychosocial factors to colds and influenza may play similar roles in COVID-19.

scholarly journals ‘Stay home when sick’ advice: implications for sport and exercise

2021 ◽  
Vol 7 (4) ◽  
pp. e001227
Author(s):  
John W Orchard ◽  
Jessica J Orchard ◽  
Rajesh Puranik
Keyword(s):  
Public Health ◽  
Respiratory Illness ◽  
The Elderly ◽  
Chronic Fatigue ◽  
Respiratory Viruses ◽  
Respiratory Illnesses ◽  
Individual Strategy ◽  
Sport And Exercise ◽  
The Right ◽  
Key Events

The coronavirus pandemic has given everyone in society an education on the harms of spread of respiratory illness. Young healthy athletes are far less likely to suffer severe adverse consequences of viral illnesses than the elderly and frail, but they are not completely immune. Chronic fatigue (overtraining) is an uncommon outcome and myocarditis a rare one, but they both warrant due consideration. It is, therefore, a sensible individual strategy to ‘stay home when sick’ if only for these risks. Traditionally though, athletes have tended to push through (train and play when ill) because of competing concerns, such as key events/matches and ‘not wanting to let teammates down’. Data from both low COVID-19 and high COVID-19 countries show that the number of cardiovascular deaths in a society correlates with the number of respiratory deaths at the same time, further linking respiratory viruses to cardiovascular deaths. We are now more aware of public health obligations to prevent the spread of respiratory illnesses, in particular to protect the more vulnerable members the community. This hopefully will correspond with a change in the culture of sport to one where it is considered ‘the right thing to do’, to ‘stay home when sick’.

Influence of Life Events and Family Routines on Childhood Respiratory Tract Illness

PEDIATRICS ◽  
1977 ◽  
Vol 60 (4) ◽  
pp. 609-615 ◽  
Author(s):  
W. Thomas Boyce ◽  
Eric W. Jensen ◽  
John C. Cassel ◽  
Albert M. Collier ◽  
Allan H. Smith ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Life Events ◽  
Psychosocial Problems ◽  
Strong Relationship ◽  
Respiratory Illness ◽  
Etiologic Agent ◽  
Upper Respiratory Tract ◽  
Family Routines ◽  
Respiratory Illnesses ◽  
Group A

Respiratory illnesses account for nearly two thirds of the total illness in a community,1 account for as much as 40% of the problems seen in a pediatric practice,2,3 and are responsible for over one third of school absences.4 Despite major advances in the microbiology of respiratory disease, why and how a child becomes ill remain poorly understood. In over half of respiratory illnesses, complete cultures fail to yield an etiologic agent.5 Conversely, 30% of a school-age population can harbor group A streptococci without developing symptoms,6 three quarters of preschool children infected with Mycoplasma pneumoniae remain asymptomatic,7 and as many as 42% of upper respiratory tract cultures from well children yield pneumococci.8 Furthermore, there is no satisfactory explanation for the observation that certain children are predisposed to more frequent or more severe respiratory illnesses.9 The limited ability of microbiologic data to account for clinical experience has increased interest in studying the influence of social factors upon childhood disease. The family is undoubtedly the most important social context in which illness occurs, and many studies have documented the link between pediatric disease and family dynamics.10-18 Meyer and Haggerty reported a strong relationship between patterns of streptococcal illness and the degree of chronic family stress.19 Another group of observers found an accumulation of major family life events in the year preceding general pediatric hospitalizations.20 Others have demonstrated the prevalence of psychosocial problems in the families of children with repeated accidents and ingestions of poisons.21,22 There has, however, been little study of the general relationship between social environment and respiratory illness in children.

Impact of influenza vaccination on respiratory illness rates in children attending private boarding schools in England, 2013–2014: a cohort study

2015 ◽  
Vol 143 (16) ◽  
pp. 3405-3415 ◽  
Author(s):  
N. BROUSSEAU ◽  
H. K. GREEN ◽  
N. ANDREWS ◽  
R. PRYSE ◽  
M. BAGUELIN ◽  
...  
Keyword(s):  
Secondary School ◽  
Influenza Vaccination ◽  
Negative Binomial ◽  
Disease Incidence ◽  
Respiratory Illness ◽  
Boarding Schools ◽  
Upper Respiratory Tract ◽  
Respiratory Illnesses ◽  
Tract Infections ◽  
The Impact

SUMMARYSeveral private boarding schools in England have established universal influenza vaccination programmes for their pupils. We evaluated the impact of these programmes on the burden of respiratory illnesses in boarders. Between November 2013 and May 2014, age-specific respiratory disease incidence rates in boarders were compared between schools offering and not offering influenza vaccine to healthy boarders. We adjusted for age, sex, school size and week using negative binomial regression. Forty-three schools comprising 14 776 boarders participated. Almost all boarders (99%) were aged 11–17 years. Nineteen (44%) schools vaccinated healthy boarders against influenza, with a mean uptake of 48·5% (range 14·2–88·5%). Over the study period, 1468 respiratory illnesses were reported in boarders (5·66/1000 boarder-weeks); of these, 33 were influenza-like illnesses (ILIs, 0·26/1000 boarder-weeks) in vaccinating schools and 95 were ILIs (0·74/1000 boarder-weeks) in non-vaccinating schools. The impact of vaccinating healthy boarders was a 54% reduction in ILI in all boarders [rate ratio (RR) 0·46, 95% confidence interval (CI) 0·28–0·76]. Disease rates were also reduced for upper respiratory tract infections (RR 0·72, 95% CI 0·61–0·85) and chest infections (RR 0·18, 95% CI 0·09–0·36). These findings demonstrate a significant impact of influenza vaccination on ILI and other clinical endpoints in secondary-school boarders. Additional research is needed to investigate the impact of influenza vaccination in non-boarding secondary-school settings.

scholarly journals Elderberry for prevention and treatment of viral respiratory illnesses: a systematic review

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
L. Susan Wieland ◽  
Vanessa Piechotta ◽  
Termeh Feinberg ◽  
Emilie Ludeman ◽  
Brian Hutton ◽  
...  
Keyword(s):  
Systematic Review ◽  
Immune System ◽  
Respiratory Infections ◽  
Ex Vivo ◽  
Respiratory Illness ◽  
Respiratory Illnesses ◽  
Respiratory Problems ◽  
Prevention And Treatment ◽  
Viral Respiratory Infections ◽  
Viral Respiratory

Abstract Background Elderberry has traditionally been used to prevent and treat respiratory problems. During the COVID-19 pandemic, there has been interest in elderberry supplements to treat or prevent illness, but also concern that elderberry might overstimulate the immune system and increase the risk of ‘cytokine storm’. We aimed to determine benefits and harms of elderberry for the prevention and treatment of viral respiratory infections, and to assess the relationship between elderberry supplements and negative health impacts associated with overproduction of pro-inflammatory cytokines. Methods We conducted a systematic review and searched six databases, four research registers, and two preprint sites for studies. Two reviewers independently assessed studies for inclusion, extracted data from studies, assessed risk of bias using Cochrane tools, and evaluated certainty of estimates using GRADE. Outcomes included new illnesses and the severity and duration of illness. Results We screened 1187 records and included five randomized trials on elderberry for the treatment or prevention of viral respiratory illness. We did not find any studies linking elderberry to clinical inflammatory outcomes. However, we found three studies measuring production of cytokines ex vivo after ingestion of elderberry. Elderberry may not reduce the risk of developing the common cold; it may reduce the duration and severity of colds, but the evidence is uncertain. Elderberry may reduce the duration of influenza but the evidence is uncertain. Compared to oseltamivir, an elderberry-containing product may be associated with a lower risk of influenza complications and adverse events. We did not find evidence on elderberry and clinical outcomes related to inflammation. However, we found evidence that elderberry has some effect on inflammatory markers, although this effect may decline with ongoing supplementation. One small study compared elderberry to diclofenac (a nonsteroidal anti-inflammatory drug) and provided some evidence that elderberry is as effective or less effective than diclofenac in cytokine reduction over time. Conclusions Elderberry may be a safe option for treating viral respiratory illness, and there is no evidence that it overstimulates the immune system. However, the evidence on both benefits and harms is uncertain and information from recent and ongoing studies is necessary to make firm conclusions.

Mortality Following Isolation of Various Respiratory Viruses in Nursing Home Residents

1999 ◽  
Vol 20 (12) ◽  
pp. 812-815 ◽  
Author(s):  
Paul J. Drinka ◽  
Stefan Gravenstein ◽  
Elizabeth Langer ◽  
Peggy Krause ◽  
Peter Shult
Keyword(s):  
Nursing Home ◽  
Influenza A ◽  
Skilled Nursing Facility ◽  
Nursing Home Residents ◽  
Respiratory Illness ◽  
Respiratory Viruses ◽  
Influenza B ◽  
Respiratory Pathogens ◽  
Syncytial Virus ◽  
Viral Respiratory

AbstractObjective:To compare mortality following isolation of influenza A to mortality following isolation of other respiratory viruses in a nursing home.Setting:The Wisconsin Veterans Home, a 688-bed skilled nursing facility for veterans and their spouses.Participants:All residents with respiratory viral isolates obtained between 1988 and 1999.Design:Thirty-day mortality was determined following each culture-proven illness.Results:Thirty-day mortality following isolation of viral respiratory pathogens was 4.7% (15/322) for influenza A 5.4% (7/129) for influenza B; 6.1% (3/49) for parainfluenza type 1; 0% (0/26) for parainfluenza types 2,3, and 4; 0% (0/26) for respiratory syncytial virus (RSV); and 1.6% (1/61) for rhinovirus.Conclusions:Mortality following isolation of certain other respiratory viruses may be comparable to that following influenza A (although influenza A mortality might be higher without vaccination and antiviral agents). The use of uniform secretion precautions for all viral respiratory illness deserves consideration in nursing homes.

scholarly journals High burden of viral respiratory co-infections in a cohort of children with suspected pulmonary tuberculosis

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
M. M. van der Zalm ◽  
E. Walters ◽  
M. Claassen ◽  
M. Palmer ◽  
J. A. Seddon ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Respiratory Viruses ◽  
Respiratory Illnesses ◽  
Viral Aetiology ◽  
High Prevalence ◽  
Observational Cohort ◽  
Future Work ◽  
Viral Respiratory

Abstract Background The presentation of pulmonary tuberculosis (PTB) in young children is often clinically indistinguishable from other common respiratory illnesses, which are frequently infections of viral aetiology. As little is known about the role of viruses in children with PTB, we investigated the prevalence of respiratory viruses in children with suspected PTB at presentation and follow-up. Methods In an observational cohort study, children < 13 years were routinely investigated for suspected PTB in Cape Town, South Africa between December 2015 and September 2017 and followed up for 24 weeks. Nasopharyngeal aspirates (NPAs) were tested for respiratory viruses using multiplex PCR at enrolment, week 4 and 8. Results Seventy-three children were enrolled [median age 22.0 months; (interquartile range 10.0–48.0); 56.2% male and 17.8% HIV-infected. Anti-tuberculosis treatment was initiated in 54.8%; of these 50.0% had bacteriologically confirmed TB. At enrolment, ≥1 virus were detected in 95.9% (70/73) children; most commonly human rhinovirus (HRV) (74.0%). HRV was more frequently detected in TB cases (85%) compared to ill controls (60.6%) (p = 0.02). Multiple viruses were detected in 71.2% of all children; 80% of TB cases and 60.6% of ill controls (p = 0.07). At follow-up, ≥1 respiratory virus was detected in 92.2% (47/51) at week 4, and 94.2% (49/52) at week 8. Conclusions We found a high prevalence of viral respiratory co-infections in children investigated for PTB, irrespective of final PTB diagnosis, which remained high during follow up. Future work should include investigating the whole respiratory ecosystem in combination with pathogen- specific immune responses.

scholarly journals Impact of Rapid Molecular Detection of Respiratory Viruses on Clinical Outcomes and Patient Management

2019 ◽  
Vol 57 (4) ◽  
Author(s):  
Jane Kuypers
Keyword(s):  
Influenza A ◽  
Rapid Test ◽  
Respiratory Illness ◽  
Respiratory Viruses ◽  
Complex Nature ◽  
Influenza B ◽  
Molecular Testing ◽  
Respiratory Illnesses ◽  
Molecular Tests ◽  
The Impact

ABSTRACT To determine if rapid molecular testing for respiratory viruses in patients with respiratory illnesses can provide advantages to patients and hospitals, rigorous investigations on the impacts of using these assays are required. Well-conducted studies are needed to inform decisions about implementation of new rapid assays to replace standard molecular testing or to initiate testing in laboratories that are currently not doing molecular tests for respiratory viruses due to the complex nature of standard panels. In this issue of the Journal of Clinical Microbiology, N. Wabe et al. (J Clin Microbiol 57:e01727-18, 2019, https://doi.org/10.1128/JCM.01727-18) report the results of their evaluation of the impact of using a rapid molecular test for influenza A/influenza B and RSV on outcomes for adults hospitalized with respiratory illness. The median time from admission to test result of the rapid test was 7.5 h compared to 40.3 h for the standard PCR assay. Compared to the use of the standard molecular assay, use of a rapid test significantly shortened time in the hospital and reduced the number of other microbiology tests performed. The authors concluded that rapid PCR testing of adults hospitalized with respiratory illnesses could provide benefits to both the patients and the hospital. Patients were able to leave the hospital earlier and a greater proportion of them had received their test results before discharge, which would allow appropriate treatment to be provided more quickly.

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