What Are the Treatments for Intestinal Parasites in Humans?

Intestinal parasites are more prevalent in third-world countries, where they contribute significantly to mortality rates. However, there are parasitic infections endemic to the United States, some of which are very common.

Common Intestinal Parasites

• In the U.S., the most common parasites include pinworms (Enterobius vermicularis); giardia (Giardia lamblia); two types of hookworms (Ancylostoma duodenale and Necator americanus); and amebas (Entamoeba histolytica). Hookworm infections were quite prevelant in the southern region of the U.S. until the early 1900s, when modern plumbing began to become the norm. However, pinworms and giardia are still very common today.

Pinworms

• Pinworms, which are the least harmful of intestinal parasites, are spread by oral-fecal contact and are the most common parasite in the U.S. Without treatment, infection lasts 4 to 6 weeks. Because pinworms often don't show up in a stool sample, an infected individual might only show signs of itching in the perianal region. Medications used to treat pinworms include Mebendazole, Pyrantel pamoate, and Albendazole. Of note is that only humans can act as a host for pinworms.

Giardia

• Giardia is the second most common intestinal parasite and is also spread by oral-fecal contact and contamination. Because it is a water-borne protozoan that survives in cold streams, giardia typically infects campers, hikers, hunters and other outdoors afficionados. Symptoms of giardiasis typically show up after one or two weeks and include nausea, vomiting, gas, stomach cramps and diarrhea. Giardiasis can become chronic if it is not treated. Medications used to treat giardiasis may include Metronidazole, Paramomycin (for pregnant women), or Albendazole.

Hookworms

• Ancylostoma duodenale and Necator americanus (hookworms) are also found only in human hosts. Hookworms enter through hair follicles and pores of the skin, where they make their way from the circulatory system to the wall of the small intestine. There, they begin to reproduce. Intestinal distress may last briefly. However, in addition to anemia, edema, and pica, the most grave risk to hookworm infection is blood loss. Hookworms may "drink" 0.25 ML of blood per day. Hookworm infections are treated with Albendazole, Mebendazole, or Pyrantel pamoate.

Amebiasis

• Ambiasis is also spread when fecal matter is inadvertantly ingested, usually when improper hygiene is used during the preparation of food, although it can also be spread through oral-anal sex. E. histolytica has two stages: Cysts, which are ingested; and trophozoites, which hatch in the small intestine and continue along the digestive tract. Amebiasis is sometimes misdiagnosed as inflammatory bowel disease because the symptoms mimic each other: Abdominal pain, bloody diahrrea, weight loss, and fever. Ambiasis can be treated with a number of medications, including Iodoquinol, Paromomycin, Diloxanide furoate, Metronidazole or Chloroquine.

How to Avoid Intestinal Parasites

• The best way to avoid intestinal parasites is to eschew places where there is poor sewage disposal and lack of water treatment. Campers should either drink bottled water or boil water for at least one minute. Other preventive measures include washing hands frequently, keeping bed linens and contact surfaces in the home clean, and not eating unpeeled, unwashed fruits and vegetables.