Sometimes the symptoms of giardiasis go away without treatment. But many people who have symptoms will choose treatment to relieve their discomfort and avoid the spread of the illness. Doctors recommend that people infected with Giardia get treated even if they don’t have symptoms. This prevents spread of the disease and reduces your risk of developing a chronic infection with the parasite.

Giardiasis is treated with antiprotozoal medicines (such as metronidazole or tinidazole) that kill the parasite. The medicine you take will depend on your age, whether you have been treated for giardiasis before, and whether you are pregnant.

If you have giardiasis, you should be treated if:

• You work in a nursing home or child care center.
• Your job involves food preparation, handling, or serving.
• You have health problems in addition to giardiasis. Even a short episode of diarrhea may cause dehydration or poor absorption of nutrients from the intestine, which may make other health problems worse.
• You have bouts of diarrhea that occur off and on for several months or more (chronic giardiasis). Many cases do get better eventually, but treatment can relieve the discomfort of symptoms and may reduce the risk of spreading the infection to others.

What To Think About

If you do not have symptoms, the decision to get tested or treated depends on your risk of spreading the parasite. It is not necessary to treat an infection that is not causing symptoms, though most doctors do recommend treatment. The medicines may not be effective for everyone. You may want to consider the cost of treatment, as well as the potential negative side effects of a medicine, when deciding whether to treat a giardiasis infection.

• If the risk of infecting others is high (such as for people who work in food services) or the likelihood of shared exposure is high (such as among family members who drink untreated water from the same source), testing and treatment should be done.
• If the risk of infecting others is low, you may want to wait and see whether symptoms develop.
• If you become reinfected with giardia after receiving treatment, you may be getting infected by others who are spreading the parasite or you may have a persistent infection.