Internal parasitic diseases are not common in the U.S., but do exist. According to MedlinePlus, the parasites range from one celled protozoa to worms seen visible with the naked eye. Infection is caused by eating or drinking contaminated food, sexual intercourse or even bug bites.
Some internal parasites, such as tapeworms, may live in a person for up to 20 years while others survive several weeks or months. Most people suffering from internal parasites have no symptoms. Severe infections may show visible signs of the worms from the anus, mouth or nose, anal itching, weight loss or other signs, depending on the parasite.
Tapeworm
Tapeworm is treated by orally administering medication that is toxic to the tapeworm. The most commonly used medications include praziquantel, albendazole and nitazoxanide. According to MayoClinic.com, the specific medication prescribed depends on the location of the infection and type of tapeworm. Testing of stool is performed one to three months after taking the medications. Most people show no signs of tapeworms, eggs or larvae if medication was correctly administered, reports MayoClinic.com. Invasive tapeworm infections require addition medications and treatment. Anti-inflammatory and anti-epileptic drugs may be required. Surgery may be necessary to remove cysts in the body caused by the parasites.
Giardia
According to MayoClinic.com, giardiasis remains the most common waterborne illness in the U.S. Treatment of the microscopic parasite takes up to six weeks, but side effects may last much longer. Treatment is not necessary, unless there is risk of spreading the disease to others. Most people do not show symptoms and the condition clears up on is own in several weeks. Conditions that do not clear up require antibiotic therapy. Common antibiotics and antiprotozoal agents prescribed include metronidazole, tinidazole and nitazoxanide.
Ascariasis
Ascariasis, also known as roundworm infection, is one of the most common internal parasite infection in the world, according to the National Institute of Allergy and Infectious Diseases. Similar to other parasitic infection, no treatment is necessary if the infection is mild. More severe infections consisting of hundreds of worms in the body. Medications are the first line of treatments, reports MayoClinic.com. The most commonly prescribed medications for ascariasis include albendazole and ivermectin. The drugs are taken as a single dose and often cause mild stomach pain and diarrhea. Occasionally, heavy infestations cause intestinal and bile duct obstruction as well as other internal injury. Though rare, surgery may be required.
