Giardia Infections Summary Giardiasis is an illness caused by a parasite called Giardia intestinalis. It lives in soil, food, and water. It may also be on surfaces that have been contaminated with waste. You can become infected if you swallow the parasite. You can also get it if you’re exposed to human feces (poop) through sexual contact. The risk of getting giardia is higher for travelers to countries where it is common, people in child care settings, and those who drink untreated water. Diarrhea is the main symptom of giardia infection. Others include Passing gas Greasy stools Stomach cramps Upset stomach or nausea These symptoms may lead to weight loss and loss of body fluids. Some people have no symptoms at all. Symptoms of infection often last two to six weeks. Stool sample tests can diagnose it. You often need to collect several samples to test. Doctors use several drugs to treat it. The best way to prevent giardia infection is to practice good hygiene, including frequent hand washing. You should not drink water that may be contaminated. You should also peel or wash fresh fruit and vegetables before eating. Centers for Disease Control and Prevention National Institute of Allergy and Infectious Diseases Find an Expert Centers for Disease Control and Prevention Centers for Disease Control and Prevention National Institute of Allergy and Infectious Diseases National Institute of Allergy and Infectious Diseases Clinical Trials ClinicalTrials.gov: Giardiasis National Institutes of Health Diagnosis and Tests Diagnosis of Parasitic Diseases Centers for Disease Control and Prevention Giardia: Illness & Symptoms Centers for Disease Control and Prevention O&P (Ova and Parasite) Test American Association for Clinical Chemistry Related Issues Giardia & Pets Centers for Disease Control and Prevention Giardia and Drinking Water from Private Wells Centers for Disease Control and Prevention Travelers’ Health: Giardiasis Centers for Disease Control and Prevention Travelers’ Health: Water Disinfection for Travelers Centers for Disease Control and Prevention Start Here Giardia Infection (Giardiasis) Mayo Foundation for Medical Education and Research Giardia: General Information Centers for Disease Control and Prevention Giardiasis American Academy of Family Physicians Treatments and Therapies Giardia Infection Treatment Centers for Disease Control and Prevention Prevention and Risk Factors Giardia Prevention and Control: General Public Centers for Disease Control and Prevention Array Giardiasis Stool ova and parasites exam Children Giardiasis (For Parents) Nemours Foundation Journal Articles Giardia Infections