Colds Overview

The cold is the most commonly occurring illness in the entire world, with more than 1 billion colds per year reported in the United States alone. The common cold is a self-limiting illness caused by any 1 of more than 200 viruses.

The common cold produces mild symptoms usually lasting only 5-10 days. In contrast, the "flu" (influenza), which is caused by a different class of virus, can have severe symptoms.

Causes of Colds

• Of the viruses that cause a cold, the most commonly occurring subtype is a group that lives in the nasal passages known as the "rhinovirus." Other less common cold viruses include coronavirus, adenovirus, and respiratory syncytial virus (RSV).
  
  
• Contrary to popular belief, the vast majority of cold viruses do not spread through the air and seldom are transmitted from airborne particles expelled when someone with a cold coughs or sneezes.
  
  
• The primary means of spreading a cold is through hand-to-hand contact or from objects that have been touched by someone with a cold.
  
  
  • The typical transmission occurs when a cold sufferer rubs his or her nose and then, shortly thereafter, shakes hands with someone who, in turn, touches his or her own nose or eyes.
    
    
  • Alternatively, virus transmission often occurs via doorknobs and other hard surfaces, such as subway handrails, grocery carts, office telephones, and computer keyboards.