What Is a Virus?
A virus is the smallest type of infectious agent. It is anywhere from one-half to one-hundredth the size of the smallest bacteria. Viruses are responsible for a wide range of diseases, from the common cold and warts, to AIDS, chickenpox, and influenza.
2,500 Years Ago: Phlegm
Hippocrates of Cos (c. 460-c. 375 B.C.E.) was the ancient Greek physician often called the father of medicine. He believed that the body contained four primary fluids (“humors”): yellow bile, black bile, blood, and phlegm.
According to Hippocrates, sickness resulted when the bodily humors became unbalanced; the common cold, for example, resulted from an excess of the humor “phlegm.” Hippocratic physicians thought that mucus discharges from the nose were a sign of the body’s effort to heal itself by releasing the excess humor.
What Are the Different Types of Viruses That Cause Colds?
There are about 200 viruses that can cause the common cold. The ones that cause colds most frequently belong to two major groups—rhinoviruses and coronaviruses.
Who Is at Risk for Colds?
Some people will say they have never had a cold, but almost everyone is at risk for catching colds. School children and young children in day care get the most colds. Some children have as many as ten colds a year.
Young children have not yet been exposed to and had the time to build up immunity to cold viruses the way older people have. Since school children are so close to each other in large numbers, they pass cold viruses along to each other. As children grow older, they get fewer colds.
A young adult may only have two or three colds a year. Older people may have only one or no colds at all.
The winter months are times when most people catch their colds. One of the reasons that winter is a time for colds is that people crowd together indoors in warm places. They tend to go to the movies, parties, and the mall in cold weather, and pass the cold viruses around to other people.
How Are Cold Viruses Transmitted?
There are three main ways cold viruses spread from one person to another:
- When someone sneezes or coughs they spray little moisture droplets containing virus particles into the surrounding air. Others nearby may inhale these droplets and then become infected as well.
- A person with a cold rubs his nose and then shakes hands with someone. The virus can be passed on if the person touches his eyes or nose or touches food with his hands. This way of catching a cold is called “via hand contact.”
- When people handle objects that have recently been handled by someone with a cold, they may have contact with the viruses. For example, picking up a book that has been handled by someone with a cold or playing cards with someone who has a cold can result in a person catching a cold.
What Parts of the Body Do Cold Viruses Affect?
Cold viruses attack the mucous linings of the nose and throat, and sometimes the eye. The tissues in the nose and throat become inflamed from the infection. The nose is stuffy, and it is hard to breathe.
What Are Symptoms of a Cold?
Some of the other symptoms of colds are:
- A tickling sensation in the throat
- Sore throat
- Stuffy and/or runny nose
- Watery eyes
- Low grade fever, up to 101 degrees Fahrenheit
Influenza, or “flu,” shares many of the symptoms of the common cold, but with the flu the fever is usually higher, and the symptoms are worse.
What Are Some Complications That Can Follow a Cold?
Sometimes rather than starting to feel better after three or four days, a person gets worse or develops new symptoms such as an earache, a worsening cough with chest pains, or a very sore throat. This may be because a bacterial infection has occurred. Sinuses may become infected with bacteria. The middle ear is another site that can become infected by bacteria. Such infections are called secondary infections.
What Is the Treatment for a Cold?
It takes about a week for a cold to clear up on its own. If it lasts much longer than that, a doctor should be consulted. Other symptoms might have to be treated if an infection spreads beyond the usual areas affected by the cold. If there is pain in the chest as a result of the infection or in other places such as the ears, a secondary bacterial infection may be present. Unlike the cold, which should not be treated with antibiotics, the bacterial infection may require the use of them.
Antibiotics and colds
Some people think that using antibiotics for a cold will help them recover more quickly or reduce the discomfort of their symptoms. Colds are caused by viruses, not bacteria. Antibiotics are effective against bacteria, not against viruses!
Overuse of antibiotics has led to the development of bacteria that are resistant to them. These new strains of bacteria have developed the ability to inactivate antibiotics or to continue to grow in spite of the presence of the antibiotic. Therefore, antibiotics should be used only when a doctor is reasonably certain that the antibiotic will be effective and that the infection is likely caused by a bacterium and not a virus.
Can the Common Cold Be Prevented?
There are many beliefs people have about preventing colds. Two of the most common:
- Can colds be prevented by keeping away from damp places or chilly drafts? In the past, people thought that drafts that chilled the body caused colds. But Ben Franklin knew better. Over 200 years ago, he wrote that colds came from contact with other people, not from chills.
- Can a cold be prevented by taking lots of vitamin C supplements? While many people believe that vitamin supplements prevent colds, there is no clear scientific evidence proving this.
There are still common sense measures that can be taken, such as resting, drinking lots of liquids, and eating a healthy diet. Aspirin should not be given to children with viral infections, since this has been linked with the risk of Reye’s syndrome (a potentially fatal condition that affects the liver and brain).
Some people recommend over-the-counter cold medicines for nasal stuffiness and coughs. These medicines often have unpleasant side effects such as sleepiness and dry mouth. Cough medicine should be used only if coughing is interfering with sleep. Use of over-the-counter medicines will not affect the amount of time of time it takes for the cold to get better and the side effects of the medication may be worse than the symptoms of the cold itself.