Cold overview.

Today we'll talk about common cold. The common cold caused by a large number of viruses. As a result we feel different symptoms in the upper respiratory tract. The main virus is usually the rhinovirus. It is the reason of about one third of colds. The other major virus is coronaviruses. These two viruses cause half of all colds. The virus enters your body through your mouth or nose. When someone touches common objects the rhinovirus is easily spread.

So what causes a common cold? There are some factors that make you more vulnerable to cold virus. It's not enough to just get wet to catch cold. Probability to catch a common cold is higher when you are under emotional stress, very exhausted or have some type of allergie.

Now, that's how common cold starts. The virus is passed from infected person to you. It happens when you breathe in the air after someone has sneezed or you touch the same surface and then touch your nose. Your body starts to send white blood cells to fight cold germs. If your immune system has never met this type of virus it starts another attack. It requires a lot of energy, you feel very tired and your nose produces a lot of moisture.

In the United States, cold happens more often during the winter and fall, especially in the northern areas.