There are hundreds of viruses. And within each type of virus there might be nearly 100 mutations. Not all of these will affect humans. For example, tobacco plants are invaded by the tobacco mosaic virus. Other viruses affect one or two kinds of animals, but not humans.
Your first and best defense against viruses is to not allow them access to your body. And although you've heard it before, it's worth repeating: Wash your hands! It's the most effective way to keep viruses from spreading.
No matter how careful you are, you can't eliminate all contact with viruses. That's where your body's defense system comes in. Your body fights off viruses with protein-like substances called interferons, which make your cells more resistant. If that's not sufficient, your immune system kicks in and kills the virus and all infected cells.
Scientists have developed vaccines against some virus-caused illnesses. A person can become immune or resistant to a particular disease by becoming infected and recovering from the disease. This can occur by natural exposure, for example, catching chicken pox from a classmate. Or, you can develop immunity through artificial exposure. This is commonly referred to as vaccination or immunization.
Immunization is a method of working with nature to preserve health. It is a procedure in which weakened or killed forms of the disease-causing agent are put into your body by mouth, injection, or other methods, so your body can build immunity to the disease the virus causes.
Since the development of immunizations, many diseases have been nearly eliminated, such as small pox, mumps, and whooping cough. |
