Giardiasis is an infection of the small intestine caused by a parasite called Giardia lamblia. The parasite produces cysts (eggs) which are passed from the body in the bowel movements or stool.

Many people have no symptoms but when symptoms do occur, they usually start 1 to 4 weeks after the parasite has entered the body. Symptoms include:

• Watery, foul-smelling diarrhea
• Gas
• Lack of appetite
• Stomach cramps
• Sometimes also fever, nausea, vomiting and headache
• Episodes of diarrhea may alternate with constipation

• The parasite leaves the body through the stool of an infected person and enters another person when hands, food, or objects (toys, pens, etc.) contaminated with stool, are put in the mouth. Spread of Giardia lamblia can occur whether or not a person feels sick.
• The parasite can be found naturally in some water supplies (such as lakes and streams).  People who drink untreated water (water from streams, lakes, etc.) may swallow the parasite and become infected.
• Some animals can have giardiasis and can pass the illness on to humans by direct contact with the animal’s stool or when the animal’s stool has contaminated the water supply.

• The infection is diagnosed by examining a stool sample under a microscope.
• Sometimes several tests must be done before diagnosis can be made.
• Giardiasis often clears up without treatment.
• People who have symptoms can be treated with prescription medications such as Quinacrine hydrochloride (HCL), Metronidazole, or Furazolidone.

• Wash hands well after going to the bathroom, after changing diapers, and before eating or preparing food. Thorough hand-washing is the best way to prevent spread of infectious diseases of the intestinal tract.
• Keep bathrooms clean and supplied with soap and clean towels.
• Clean and disinfect areas such as potty chairs, toilets, diapering areas, which have been contaminated by stool, as follows:
  • Scrub clean with soap and water.
  • Spray surface with a commercial disinfectant or with a bleach solution (Use 1/4 cup of liquid household bleach to a gallon of water).
  • Let the surface air dry.
• Discourage children from putting objects in their mouths, especially when sharing toys with other children.
• Children who attend child care centers should be kept at home if they have diarrhea.
• The stool samples of other people who develop symptoms should be checked.