Besides vaccination, there are other measures that can be used to help the body's natural defenses fight off infectious diseases. Bacterial infections can often be conquered by medications called antibiotics. These are substances derived from living microorganisms that kill other microorganisms.
Penicillin, for example, comes from a living mold called Penicillium. Penicillin is one of the most commonly used antibiotics, along with cephalosporins, tetracycline, and erythromycin. Each of these is effective against specific diseases. Antibiotics work either by destroying bacteria or by preventing their reproduction. Sulfonamides, or sulfa drugs, are synthetic antibiotic drugs that also are effective against infections. This type of drug is often prescribed for localized infections in the urinary tract.
Unfortunately, these medications do not attack viruses. Viruses, therefore, are responsible for many of the serious or fatal infectious illnesses today because no generally effective cures have been developed. The virus that causes acquired immunodeficiency syndrome (AIDS) is an example of a virus for which there is no cure or vaccine.
Researchers are continually searching for new ways to help the body combat infectious diseases. Medical advances against these diseases have already been dramatic; not too many years ago, infectious diseases were uncontrollable and thus a constant danger. The control of many infections has been one of medicine's greatest accomplishments.