Cold, Common. The common cold results from any of a number of viral infections of the upper respiratory tract. It is the most widespread and common of all diseases. Although many people consider colds to be minor illnesses, colds are a major cause of absence from school and work. Every year, colds cost billions of dollars in lost working hours.
Common-cold infections vary in severity from a mild cold without fever to extensive, fatal pneumonia. Scientists have identified the more than 100 viruses that cause these illnesses. The majority of viruses that cause colds are classified into two large groups called rhinoviruses and coronaviruses. The different varieties of these viruses can cause similar illnesses. However, one cold virus does not give immunity against another.
People of all ages are susceptible to colds. But children—and adults living with children—seem to be most susceptible.
Symptoms.
Colds are viral infections of the mucous membranes of the nose, throat, and, sometimes, of the air passages and lungs. A person with a cold usually has a stuffy nose and may have difficulty breathing. The infection may spread to the ears, sinuses, and eyes. In many cases, it spreads to the throat, causing soreness and hoarseness. When colds spread to the air passages and lungs, they may cause bronchitis and pneumonia.
The simplest kind of cold lasts a few days. More severe colds may last longer, often causing fever and aches and pains throughout the body. Occasionally, the patient also has chills and a loss of appetite.
Colds can be dangerous because they make people more susceptible to other infections, particularly bacterial infections of the ears, sinuses, and lungs. Colds are especially dangerous to the elderly and to people who have lung ailments or are weakened by poor health.
Treatment.
Some studies suggest that taking a mineral called zinc as soon as symptoms begin may make colds shorter and less severe. Pain-relieving drugs may lessen muscle aches and pains. Nasal sprays and drops may be used for a limited time to shrink mucous membranes and make breathing easier. Vaporizers may also provide relief. A patient who has a fever should stay in bed. Staying in bed provides rest and isolates the patient from other people.
People with colds should eat nourishing foods and drink plenty of fluids, such as fruit juices, tea, or water. If the cold persists or seems to get worse, a doctor should be called. If complications begin to develop, the doctor can treat them early.
Spread.
Experts do not know all the ways in which cold germs spread. But doctors believe that a person can get a cold by breathing in the germs. Whenever a person with a cold coughs or sneezes, tiny droplets of moisture that contain cold germs spray out into the air. For this reason, colds seem to spread most rapidly in places where many people gather together, such as in schools, offices, theaters, or buses. A person should always cover the mouth and nose when coughing or sneezing. Then the germs cannot spray out into the air. Doctors also believe that cold germs can spread by direct contact, especially when the hands touch the mouth or nose.
Prevention.
Colds are transmitted by people who have them. Therefore, isolating people who have colds is one of the best ways to prevent colds from spreading. Simple hygiene practices, such as frequent hand washing, can help control the spread of colds.
Although scientists have developed several vaccines for cold viruses, none has proved effective against all types of colds. The virus that causes influenza causes some colds. People who get a flu vaccination each year may get some additional protection from colds.
The cells of human beings produce chemicals called interferons that help fight some cold viruses. Scientists have found ways of obtaining interferons by laboratory processes. See Interferon.
See also Respiratory syncytial virus (RSV).
