The Flu: Why Winter? An Age-old Question Answered Accidentally

Posted by Sara Carpenter on Nov 30, 2020 1:49:00 PM
Sara Carpenter
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A cough here. A sneeze there. Body aches.

These symptoms typically signaled influenza before 2020, but amid the COVID-19 global pandemic, patients with these symptoms may jump to conclusions. Before fearing the worst or making an assumptive diagnosis, it’s important to know that many fall and winter respiratory illnesses – influenza, COVID-19, the common cold rhinovirus, respiratory syncytial virus (RSV) and other seasonal illnesses – share common symptoms but are caused by different viruses.


It’s That Time Again

This time every year, influenza is on the American radar. Temperatures have dropped, the air is dry, flu infections are counted across the country and people share a common wonder: why winter?

To answer the age-old question why influenza spreads primarily in winter months, the microbiology department at Mount Sinai School of Medicine in New York stumbled upon a cue in a paper published in 1919 in the “Journal of the American Medical Association” following the 1918 Spanish flu epidemic. The paper noted that very soon after the influenza reached Camp Cody in New Mexico, its laboratory guinea pigs began to die, and a necropsy revealed unmistakable signs of pneumonia.


The Impact of Temperature and Humidity

Based on that one cue, the Mount Sinai research team exposed several of their research guinea pigs to the flu virus, which spread quickly among the laboratory’s guinea pig population. The team experimented with temperature and humidity variations in the guinea pigs’ quarters, revealing rapid virus transmission at 41 degrees and at humidity below 20 percent, declining transmission as temperatures and humidity increased, and no transmission at 86 degrees and 80 percent humidity. These research findings were published in October 2007 in “PLoS Pathogens,” pinpointing the virus itself as the reason for the spread: Influenza is more stable in cold air and lingers in low humidity.

Interestingly, the very name ‘influenza’ is an Italian word rooted in what historians believe originated in the mid-18th century term ‘influenza di freddo,’ which translates to ‘influence of the cold.’ That name certainly ties to the coldest months that mark flu season from November to March in northern latitudes and May to September for southern latitudes. It also explains why there is no real flu season in the tropics.


The Two Words of 2020: Virus and Testing

If there are two words we’ve heard countless time during 2020, it’s ‘virus’ and ‘testing.’ With flu season and other viruses now ramping up during the colder, lower-humidity months, it’s more important than ever to test and identify a patient’s specific respiratory virus and to develop a treatment plan, stop the spread and protect the population.

Diax LabsTM offers molecular testing that is ordered frequently by family doctors, internal medicine physicians and pediatricians. Only performed elsewhere in a hospital setting, our distinguishable molecular testing:

√ Uses target gene assays for 18 respiratory bacteria viruses

√ Identifies bacteria and viruses associated with upper and lower respiratory infections

√ Diagnoses upper respiratory issues via highly advanced respiratory pathogens and molecular bacteriology

√ Is inordinately more sensitive and more specific than rapid assays commonly performed in healthcare clinics

√ Provides robust 24-hour validation


Removing all doubt and ensuring a specific accurate diagnosis is particularly crucial amid the potential for multiple strains of influenza that are simultaneous with reported second and third waves of COVID-19 in certain states, as well as other seasonal illnesses and 14 viruses associated with acute respiratory disease, including Coronavirus HKU, Coronavirus NL63, Coronavirus 229E and Coronavirus OC43.

Molecular Diagnostics:  Key Benefits

  • Comprehensive, expeditious results
  • Implementation of infection-control measures, if necessary, to prevent further transmission in the population
  • Improved patient outcomes
  • Antibiotic de-escalation
  • Fewer secondary complications
  • Accurate target therapy decisions
  • Lower healthcare costs

Based on reverse transcription polymerase chain reaction, Diax LabsTM molecular testing accurately diagnoses respiratory syncytial virus (RSV), which can be severe in young children and deadly for seniors. And as a result of our techniques and transcription for specific, more sensitive systems of pathogen detection, pneumonia also has a highly improved diagnosis rate.


Here to Assist You

Are you an independent family physician, internal medicine doctor, pediatrician or laboratory marketing professional who sells to these independent physicians?

We welcome the opportunity to talk with you about the industry-leading molecular diagnostic testing available from Diax LabsTM. For more information or to schedule a virtual presentation, please click Learn More below.


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Topics: Blog