If you’d like to get technical, a cold can be called nasopharyngitis, rhinopharyngitis or acute coryza. Often, it’s an infection with rhinovirus, but more than 200 other viruses can cause the coughing, sore throat, runny nose and sneezing that we call the common cold. Since colds have long been associated with the chilly, wet weather of winter, that’s likely where they picked up their easily recognized name.
More recently, humans have recognized that viruses are the true cause of colds and speculated that the close contact with others when we are forced indoors by the weather might be to blame for the cold-season association. But the old folk wisdom might have some truth: Researchers have just found a way to explain how getting cold might give you a cold.
Rhinoviruses, which are the most common cause for colds, are better able to reproduce at temperatures just below the body’s 98.6 degrees Fahrenheit. To find out why, a group of scientists studied how a mouse-adapted cold virus fared in rodent lungs and nasal cavities, reports Monte Morin for the Los Angeles Times. He writes:
What they discovered was that when a virus invaded warmer cells, the host cells produced significantly more interferons -- proteins that "interfere" with the spread of a virus by warning healthy cells of its presence and setting off an immune response.
In the cooler nasal cavity cells, this warning system was less efficient however, and allowed the virus to spread more easily.
Previously, researchers had discovered that cold viruses prefer the cooler temperatures of the nose, but the new study emphasizes the influence of the host’s response on the virus’s ability to replicate. The researchers published their findings in the Proceedings of the National Academy of Sciences.
The discovery "could explain why the rhinovirus causes colds and is less able to cause more serious lung infections, like influenza does," says Jonathan Bell, a virologist at the University of Nottingham and not involved in the study, told the BBC. But more immediately relevant for those about to venture outdoors, we now know that covering your nose might actually help it stay cold-free, in more than one way.