Intestinal parasite

From ArticleWorld

An intestinal parasite is an organism that relies on the nutrition it derives from the intestinal tract of the host in order to survive. Parasites, in general, cannot live long outside of a host organism. Intestinal parasites often come from contaminated food via a route known as the “fecal-oral” route, meaning that the infection spreads when one doesn’t wash the hands and touches food or water that subsequently contaminate others.

Types

There are three main types of intestinal parasites. Protozoans such as Giardia consist of only one cell and are often passed via contaminated water supplies. Nematodes or “round worms” and cestodes (tapeworms) also are classified as intestinal parasites. Some parasites, such as Trichinella spiralis, have an intestinal phase followed by a systemic phase where the entire body is afflicted.

Symptoms

Symptoms of intestinal parasites vary with the type of infection. In some cases, the host has few or no symptoms at all. In Giardia infestations, symptoms include abdominal cramps, diarrhea and possibly abdominal bloating or bloody stools. Some individuals can be infected with Giardia for many months with mild symptoms before the condition is recognized.

Amoebiasis is a condition where the protozoan, Entamoeba histolytica, infects the gastrointestinal tract with symptoms very similar to those of Giardia. Other intestinal protozoa yield similar symptoms but are seen primarily in those who are immunosuppressed, such as those with HIV.

Intestinal tapeworms or cestodiasis is caused by swallowing the eggs of a tapeworm. Symptoms are not common but can include vomiting, fatigue and weight loss. Often the disease is not recognized until an individual passes a portion of the segmented worm and notices it in the stool.

Roundworm infections are not common. Perhaps the most commonly seen roundworm seen in developed countries is ascariasis, caused by the worm, Ascaris lumbricoides. Ascariasis affects 1.3 billion humans worldwide.

The infection begins when an individual swallows the eggs from a mature worm. The eggs mature into larvae that travel to the lungs and cause symptoms of coughing and shortness of breath. The larvae are then coughed up and swallowed where they mature to lengths of 12-14 inches and release eggs of their own. The entire process takes up to 75 days.