Tuesday, January 6, 2015

Rhinovirus Replicates Best in the Nasal Cavity

It's that time of year, eh?  Cold and flu season.  And this week we have news from researchers giving us a bit more insight into the rhinoviruses that cause the common cold.

The unsurprising new discovery is that rhinoviruses replicate more efficiently—and therefore cause colds more effectively—in the nasal cavity than in the lungs because of a temperature difference.  In mice, the animals used in the recent study, the immune mechanisms that fight off rhinoviruses work better in the warmer environment of the lung than in the cooler environment of the nasal cavity.

This phenomenon may be why a cold generally doesn't wreak the same havoc in lungs as do other respiratory viruses like influenza viruses.  Rhinoviruses, as their name implies, generally remain limited to the nose.

What can we use from this in teaching undergraduate A&P?

  • When discussing the nasal cavity's vascularity and air-warming functions, we may want to point out that understanding the temperature gradient between the nose and lower respiratory tract has practical clinical applications.  Such as why some pathogens are limited to the nose. And why cold weather may contribute to rhinvirus infection.

  • When discussing immunology, we may want to mention that body temperature—and sometimes organ temperature—can have an impact on how efficiently our immune mechanisms fight infection.

  • One could consider steering a conversation about "there is still no cure for the common cold" to a conversation about the fact that scientists are still working on understanding rhinoviruses—"and, oh, did you hear the latest .....?"

Want to know more?

Where Rhinovirus Replicates Best
  • Tracy Vence,  The Scientist.  Online. January 6, 2015.
  • Plain-English summary of the discovery.
  • my-ap.us/1FgWKr7

Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells
  • Ellen F. Foxman, et al.  Proceedings of the National Academy of Science. Online. January 5, 2015. doi: 10.1073/pnas.1411030112 
  • Original research paper.
  • my-ap.us/1xA4v6m
Photo credit: mcfarlandmo

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