Parasites live in or on another organism, known as the host, from which they receive nourishment and protection. Some pass successive stages of maturity in hosts of different species, including humans. Parasites are of different types, including protozoa (one-celled animals) and helminths (worms) ranging in size from microscopic eggs to adults up to several feet long. The illnesses they cause range from mild discomfort of short duration to chronic, debilitating disease and death.
People who live in areas where the disease is endemic (constantly present) suffer the devastation most keenly. Hardest hit are developing countries in the tropics, where poor sanitation fosters the parasites and the insects that transfer many of them from one host to another.
Parasite infection may cause many different symptoms, most of which are common to other diseases. Therefore, people with parasites may not suspect them as the culprit. Since parasites disturb the ecology of the intestine, many of their effects are seen in digestive problems, including constipation, diarrhea, gas and bloating, persistent bad breath, and irritable bowel syndrome. Other health problems that may result indirectly from a disturbance in intestinal ecology include joint and muscle aches and pains (fibromyalgia syndrome), anemia, allergies, skin problems, nervousness, depression, sleep disturbances, teeth grinding, persistent fatigue, immune dysfunction, and uncontrolable sugar cravings.
Of course, not every case of ill health can be blamed on parasites. If, however, symptoms persist after you've been treated for some other suspected ailment, or if the symptoms recur at regular intervals, then parasites should be suspected. It is a good idea to keep track of your symptoms and look into the possible cause of a parasite with the help of a qualified health-care provider. Diagnosis usually must be performed by a laboratory that specializes in parasite testing (see Resources).
If you learn you have parasites, you will want to follow a program aimed at eradicating the parasites instead of merely relieving the symptoms of infection. If the parasites are not eliminated, they will continue to reproduce and create problems. Parasites cause harm in part by overrunning the populations of beneficial microflora in the intestine that aid in maintaining proper digestive activity. They also produce toxic byproducts.
When symptoms are severe, as may occur with certain parasites such as Giardia, doctors generally will prescribe drugs like Flagyl, Atabrine, and Vermox, any of which will usually get rid of the parasites. Many individuals, however, experience adverse reactions to these medications, such as nausea or psychiatric disturbances. Therefore, for less serious infections, you may wish to discuss with your doctor a series of simple steps that change the environment in the intestine to make it less amenable to the parasites' survival.
