About... Giardiasis

What is giardiasis?

Giardiasis (gee-are-DYE-a-sis) is a contagious disease caused by a one-celled parasite, Giardia lamblia, which is found in the intestines of many animals. During the past two decades, Giardia infection has become recognized as one of the most common causes of waterborne disease (found in both drinking and recreational water) in the United States. Because the parasite is protected by an outer shell (cyst), it can survive outside the body and in the environment for long periods of time. Concentrations of chlorine used in routine water treatment do not kill Giardia cysts. From 1997-2000, there was an average of 665 cases of giardiasis reported in Indiana every year.

How is giardiasis spread?

Giardia is passed in the stool, and people become infected by ingesting feces from an infected animal or person (fecal-oral route).

There are several ways to become infected with Giardia:

• Having contact with an infected person’s stool:
  • Not washing hands after contact with stool from a contaminated surface or diaper/linen and ingesting the bacteria.
  • Having sex that involves contact with stool.
• Swallowing untreated water, e.g., from lakes or streams.
• Swallowing treated but unfiltered drinking or recreational water.
• Direct contact with the stool of infected cattle, livestock, and animals from petting zoos.

Giardiasis is more common in children than adults. Large community outbreaks have occurred from drinking treated but unfiltered water. Smaller outbreaks have resulted from contaminated food, person-to-person transmission in day care facilities, and contaminated recreational waters.

What are symptoms of giardiasis?

• Diarrhea
•  Gas
• Greasy stools that tend to float
• Bloating
• Stomach cramps
• Nausea
• Constipation

Symptoms usually begin within 7-10 days (range of 3-25 days) after exposure and last 2-6 weeks. These symptoms may lead to weight loss and dehydration, but some persons infected may have no symptoms. Infected people may carry Giardia in their bodies for weeks or months without symptoms and unknowingly infect others.

How do I know if I have giardiasis?

A person having diarrhea lasting more than 24 hours should consult a health care provider. The health care provider may collect several stool samples before the tests are positive for Giardia.

How is giardiasis treated?

While medications are available for giardiasis, they are not needed if the person does not have diarrhea. Over-the-counter drugs may relieve symptoms but will not get rid of the parasite.

Is giardiasis a reportable disease?

Yes. Health care providers or laboratories must report cases of giardiasis to the local health department (LHD) or the Indiana State Department of Health (ISDH) within 72 hours of diagnosis. The LHD will contact all cases diagnosed with Giardia to determine a possible exposure and help prevent others from becoming ill.

How can giardiasis be prevented?

In general, giardiasis can be prevented by strictly adhering to the following guidelines:

• Practice good hygiene:
  • Thoroughly wash hands with soap and water after using the restroom; after assisting someone with diarrhea and/or vomiting; after swimming; before, during, and after food preparation (please refer to Quick Facts about Hand Washing)..
  • Clean food preparation work surfaces, equipment, and utensils with soap and water before, during, and after food preparation.
• Separate raw and cooked foods:
  • Avoid cross-contamination by separating produce, ready-to-eat foods, and cooked foods.
  • Use separate equipment and utensils for handling raw foods.
• Eat safe foods and drink safe water (Remember: Contaminated foods may look and smell normal):
  • Do not consume unpasteurized dairy products or juices.
  • Wash all produce before eating raw or cooking.
  • Use treated water for washing, cooking, and drinking.
  • Avoid swallowing untreated water.
  • Test your well if:
    • Members of your family or others who use the same water are becoming ill,
    • The well is located at the bottom of a hill or it is considered shallow, or
    • The well is in a rural area where animals graze.
• Protect others:
  • Persons with diarrhea and/or vomiting should not prepare food or provide health care for others and should limit direct contact with others as much as possible.
  • Persons with diarrhea and/or vomiting should not attend a day care facility or school.
  • Persons with diarrhea and/or vomiting shall be excluded from employment involving food handling (Indiana Retail Food Establishment Sanitation Requirements, 410 IAC 7-24-122).
  • Do not change diapers near recreational water.
  • Do not go swimming or use hot tubs if you have diarrhea and for at least 2 weeks after diarrhea stops.
• Handle animals safely:
  • Wash hands after contact with livestock, petting zoos, pets, especially if they are suffering from diarrhea.
  • Have pets checked for parasites by your veterinarian, especially if they have diarrhea.
• Safe travel outside of the United States:
  • Drink bottled beverages and water, even when brushing teeth
  • Do not eat uncooked fruits or vegetables unless you peel them yourself.
  • Do not eat foods or beverages from street vendors.
  • Do not consume local water or ice.

Where can I learn more about giardiasis?

To search Indiana data and statistics:
www.in.gov/isdh/dataandstats/disease/diseases_index.htm

To search the Indiana Food Protection Program:
http://www.in.gov/isdh/regsvcs/foodprot/index.htm

To search disease information:
http://www.cdc.gov/ncidod/dpd/parasites/giardiasis/default.htm

http://www.cfsan.fda.gov/~mow/chap22.html

To search for national data, statistics, and outbreaks:
www.cdc.gov/mmwr/

 Updated on January 9, 2009