What is Giardiasis?

Giardia is a microscopic animal that lives in freshwater and feces. When people accidentally drink water with giardia living in it, the giardia makes a new home in the human intestine. This causes the medical condition known as giardiasis.

Killing the giardia is paramount to getting cured. Dogs and cats also get giardiasis but they need treatments that differ from human treatments. It is possible to contract giardiasis from an infected pet but unlikely. Babies that have been infected can pass on the parasites through their feces and diapers. Infected men may spread the parasite through unprotected anal sex. It is important to use condoms, drink only boiled water when tap or bottled water is unavailable and wash hands often to prevent many illnesses, including giardiasis.

What are the Symptoms of Giardiasis?

Common symptoms include diarrhea or stools that appear greasy, abdominal cramps or other pains, gas, bloating, constant fatigue, headaches, nausea with or without vomiting and loss of appetite. People who begin to show symptoms have been infected with the microscopic parasite for at least one week.

Unusual symptoms are swollen joints, swollen eyes, itchy skin and hives on the skin. Over time, the person loses weight no matter how much he or she eats.

People who are affected by excessive vomiting and diarrhea are at high risk of becoming dangerously dehydrated. If the person cannot keep down water and has trouble staying awake, they should call a doctor at once.

How is Giardiasis Treated?

Patients can kill off the parasites with anti-parasite drugs or antibiotics like metrodinazole or tinidazole (brand name Tindamax). Depending on how heavily the patient is infested, treatments may range from one dose to many days taking pills or liquid medications. Patients who cannot keep medication down may need medication given intravenously.

These medications can cause birth defects. Pregnant women or women who think they may be pregnant need to tell their doctors about their condition before taking any medication. Paromomycin is the gentlest antibiotic to give pregnant women.

Last Reviewed:
September 21, 2016
Last Updated:
August 09, 2017