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Why is there a "flu season"? - (Mar/29/2006 )

Does anyone know why there is a "flu season"? Why does the flu get to more people at a certain times of year? Also in the term "flu season" does "flu" refer to influenza?


Season simply refers to the fact that many people are getting sick at one point in time.

The flu get's more people in colder weather. Cold weather does not cause infections. Yes, most colds occur in winter, but that's because we stay indoors, exposed to others who are sick. Plus, typically dry cold weather removes moisture from our airways, making them more susceptible to infection.

Flu should refer to influenza, but in everday-speak it actually means fever, chills, dry cough, muscle aches, extreme fatigue, sore throat, headache, and stuffed noses.
Usually people say cold or flu without really thinking too mcuh about it, but they are two different conditions. A flu is from one family of virus, and a cold is another virus family.



Someone else may have more details on this, but I was under the impression that the flu season was a direct result of the life cycle of the influenza virus' natural home - in some species native to China. I don't recall the details and may be way off base but it is a really interesting concept.


The basic life cycle is: Genome enters host cell. Genome appropriates host metabolic equipment and causes it to replicate viral nucleic acid and to transcribe the viral genome thereby making new viral genomes (replication) and capsids (transcription and translation) using host amino acids, nucleotides, enzymes, and ribosomes. The two are assembled and released as infective viral particles. There are MANY variations and elaborations of this basic pattern. With the flu, this usually takes 3 days.

According to "Seasonal Variation in Host Susceptibility and Cycles of Certain Infectious Diseases", Seasonal cycles of infectious diseases have been variously attributed to changes in atmospheric conditions, the prevalence or virulence of the pathogen, or the behavior of the host. If you have the time, really check out this article.

You can actually catch the flu at any time. It's just more common to catch it when the weather turns cold.



Oh, I see. Thanks for answering my post.