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Giardia infection

Giardia; G. duodenalis; G. intestinalis; Traveler's diarrhea - giardiasis

 

Giardia, or giardiasis, is an infection of the small intestine. A tiny parasite called Giardia lamblia causes it.

Causes

 

The giardia parasite lives in soil, food, and water. It may also be found on surfaces that have come into contact with animal or human waste.

You may become infected if you:

  • Are exposed to a family member with giardiasis
  • Drink water from lakes or streams where animals such as beavers and muskrats, or domestic animals such as sheep, have left their waste
  • Eat raw or undercooked food that has been contaminated with the parasite
  • Have direct person-to-person contact in daycare centers, long-term care homes, or nursing homes with people who are infected with the parasite
  • Have unprotected anal sex

Travelers are at risk for giardiasis throughout the world. Campers and hikers are at risk if they drink untreated water from streams and lakes.

 

Symptoms

 

The time between becoming infected and symptoms is 7 to 14 days.

Diarrhea is the main symptom. Other symptoms include:

  • Abdominal gas or bloating
  • Headache
  • Loss of appetite
  • Low-grade fever
  • Nausea
  • Weight loss and loss of body fluids

Some people who have had a giardia infection for a long time continue having symptoms, even after the infection is gone.

 

Exams and Tests

 

Tests that may be done include:

  • Stool antigen test to check for giardia
  • Stool ova and parasites exam
  • String test (rarely performed)

 

Treatment

 

If there are no symptoms or only mild symptoms, no treatment may be needed. Some infections go away on their own within a few weeks.

Medicines may be used for:

  • Severe symptoms or symptoms that do not go away
  • People who work in a daycare center or nursing home, to reduce the spread of disease

Antibiotic treatment is successful for most people. A change in the type of antibiotic will be tried if symptoms do not go away. Side effects from some of the medicines used to treat giardia are:

  • Metallic taste in the mouth
  • Nausea
  • Severe reaction to alcohol

In most pregnant women, treatment should not start until after delivery. Some drugs used to treat the infection can be harmful to the unborn baby.

 

Possible Complications

 

These complications can occur:

  • Dehydration (loss of water and other fluids in the body)
  • Malabsorption (inadequate absorption of nutrients from the intestinal tract)
  • Weight loss

 

When to Contact a Medical Professional

 

Call your health care provider if:

  • Diarrhea or other symptoms last for more than 14 days
  • You have blood in your stool
  • You are dehydrated

 

Prevention

 

Purify all stream, pond, river, lake, or well water before drinking it. Use methods such as boiling, filtration, or iodine treatment.

Workers in daycare centers or institutions should use good handwashing and hygiene techniques when going from child to child or person to person.

Safer sexual practices may decrease the risk for getting or spreading giardiasis. People practicing anal sex should be especially careful.

Peel or wash fresh fruits and vegetables before eating them.

 

 

References

DuPont HL. Approach to the patient with suspected enteric infection. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 283.

Haines CF, Sears CL. Infectious enteritis and proctocolitis and bacterial food poisoning. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 110.

Nash TE, Hill DR. Giardiasis. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 351.

Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 140.

 
  • Digestive system

    Digestive system - illustration

    The esophagus, stomach, large and small intestine, aided by the liver, gallbladder and pancreas convert the nutritive components of food into energy and break down the non-nutritive components into waste to be excreted.

    Digestive system

    illustration

  • Giardiasis

    Giardiasis - illustration

    Giardiasis is an intestinal infection caused by a protozoan and is spread by contaminated water or contact with an infected person. People who are travelling or hiking should assume water sources are contaminated and either purify drinking water or drink bottled water. Healthcare or daycare workers should practice good hygiene when going from person to person. Unprotected anal sex can also transmit Giardiasis from an infected person to the partner.

    Giardiasis

    illustration

  • Institutional hygiene

    Institutional hygiene - illustration

    Workers in daycare centers or institutions such as hospitals and eldercare should use good handwashing and hygienic techniques when going from child to child or patient to patient.

    Institutional hygiene

    illustration

  • Digestive system organs

    Digestive system organs - illustration

    The digestive system organs in the abdominal cavity include the liver, gallbladder, stomach, small intestine and large intestine.

    Digestive system organs

    illustration

    • Digestive system

      Digestive system - illustration

      The esophagus, stomach, large and small intestine, aided by the liver, gallbladder and pancreas convert the nutritive components of food into energy and break down the non-nutritive components into waste to be excreted.

      Digestive system

      illustration

    • Giardiasis

      Giardiasis - illustration

      Giardiasis is an intestinal infection caused by a protozoan and is spread by contaminated water or contact with an infected person. People who are travelling or hiking should assume water sources are contaminated and either purify drinking water or drink bottled water. Healthcare or daycare workers should practice good hygiene when going from person to person. Unprotected anal sex can also transmit Giardiasis from an infected person to the partner.

      Giardiasis

      illustration

    • Institutional hygiene

      Institutional hygiene - illustration

      Workers in daycare centers or institutions such as hospitals and eldercare should use good handwashing and hygienic techniques when going from child to child or patient to patient.

      Institutional hygiene

      illustration

    • Digestive system organs

      Digestive system organs - illustration

      The digestive system organs in the abdominal cavity include the liver, gallbladder, stomach, small intestine and large intestine.

      Digestive system organs

      illustration

    A Closer Look

     

      Talking to your MD

       

        Self Care

         

          Tests for Giardia infection

           

           

          Review Date: 3/13/2016

          Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

          The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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