scholarly journals Temperature dependent viral tropism: 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 L. Bach
Keyword(s):  
Temperature Dependent ◽  
Viral Tropism ◽  
Respiratory Illnesses ◽  
Viral Respiratory

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 The relationships among immunoglobulin levels, allergic sensitization, and viral respiratory illnesses in early childhood

2010 ◽  
Vol 21 (6) ◽  
pp. 990-996 ◽  
Author(s):  
Michael E. Possin ◽  
Stephanie Morgan ◽  
Douglas F. DaSilva ◽  
Christopher Tisler ◽  
Tressa E. Pappas ◽  
...  
Keyword(s):  
Early Childhood ◽  
Allergic Sensitization ◽  
Respiratory Illnesses ◽  
Immunoglobulin Levels ◽  
Viral Respiratory

scholarly journals Stroke Following Positive Biomarker for Viral Respiratory Illnesses

2020 ◽  
Author(s):  
A. Subramanian ◽  
M.K. McGraw ◽  
J. Carlin ◽  
K. Zolfaghari ◽  
J. Ettlinger ◽  
...  
Keyword(s):  
Respiratory Illnesses ◽  
Viral Respiratory

scholarly journals Role of Probiotics in Stimulating the Immune System in Viral Respiratory Tract Infections: A Narrative Review

Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3163
Author(s):  
Liisa Lehtoranta ◽  
Sinikka Latvala ◽  
Markus J. Lehtinen
Keyword(s):  
Immune System ◽  
Respiratory Tract ◽  
Clinical Studies ◽  
Viral Infections ◽  
Narrative Review ◽  
Virus Infections ◽  
Respiratory Illnesses ◽  
Upper Respiratory ◽  
Tract Infections ◽  
Viral Respiratory

Viral respiratory tract infection (RTI) is the most frequent cause of infectious illnesses including the common cold. Pharmacological solutions for treating or preventing viral RTIs are so far limited and thus several self-care products are available in the market. Some dietary supplements such as probiotics have been shown to modulate immune system function and their role in reducing the risk and the course of RTIs has been investigated extensively within the past decade. However, the mechanism of action and the efficacy of probiotics against viral RTIs remains unclear. We searched PubMed, Google Scholar, and Web of Knowledge for pre-clinical and clinical studies investigating the effect of probiotics on respiratory virus infections, immune response, and the course of upper and lower respiratory tract illness. The literature summarized in this narrative review points out that specific probiotic strains seem effective in pre-clinical models, through stimulating the immune system and inhibiting viral replication. Clinical studies indicate variable efficacy on upper respiratory illnesses and lack proof of diagnosed viral infections. However, meta-analyses of clinical studies indicate that probiotics could be beneficial in upper respiratory illnesses without specific etiology. Further studies aiming at discovering the mechanisms of action of probiotics and clinical efficacy are warranted.

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