Question: When you get a cold is it because a cold is a virus or is it because you didnt wear enough clothes so you have a cold? Im never really sure if its a virus or if its because of the weather and temperature.

Stephen Curry answered on 21 Jun 2010:

Colds are more associated with cold weather – as in winter – but it is possible to catch one in the summer because the disease is usually caused by a virus.

Several different viruses can all give you the symptoms that we would normally associate with a cold (mild fever, runny nose, sneezing) but the most common cause is human rhinovirus.

Strangely, this type of virus is closely related to foot-and-mouth disease virus (which I work on). They belong to the same family. It is a tiny particle (only about 0.00003 mm wide) that consists of a protein shell surrounding a single molecule of RNA. RNA is very like DNA and carries the virus genes.

The virus doesn’t ‘mean’ to cause any harm – it is only out to make copies of itself. But because it infects cells in your mouth, throat and nose, it ends up being rather unpleasant (though not nearly as serious as other viruses that you could catch).

On reason why transmission of the virus may be more common in winter is that people spend more time indoors with one another. It may also be that the colder temperature and dampness of the atmosphere allows the virus to survive longer when it is on the journey from one infected individual to another.