Giardiasis

Disease Fact Sheet

What is giardiasis?

Giardiasis is a disease of the small intestine caused by the parasite Giardia lamblia.

What are the symptoms?

Typical symptoms are diarrhea or loose, foul-smelling, greasy stools, cramping, bloating, excessive gas production and fatigue. Fever and vomiting are rarely experienced. Weight loss may occur if symptoms are severe or long lasting. Because fats are not well absorbed, symptoms may become worse after eating fatty foods. Symptoms typically last 3-20 days. In some cases symptoms may occur intermittently for weeks to months.

Some persons and animals may be infected with Giardia, and able to transmit to others, without showing any signs of illness.

How soon do the symptoms appear?

The incubation period is usually 5-15 days, with an average of 7-10 days.

How do you get it?

Giardiasis is transmitted by fecal-->oral spread. The parasites are excreted in the feces (stools) of people and animals who are infected with Giardia. You get it by eating food or drinking water that has been contaminated with feces from infected people or animals. You can also get it if your hands become contaminated and you eat with your hands or put your hands in your mouth. Because of this, the parasite may be easily spread within the family unit and between small children.

The parasites are commonly present in surface water. People and pets can be infected by drinking untreated river or lake water. Giardia is also in the droppings of infected animals (dogs, cats, beaver, etc.).

Giardiasis is NOT spread by coughing, sneezing or sharing drinks and eating utensils.

How do you find out if you have it?

Your doctor or clinic can test a sample of your stool (called an Ova & Parasite exam) to see if you are infected. Because the parasite is excreted off and on, sometimes you may have to submit 2 or 3 stool samples before the laboratory can identify the parasite. Even if a laboratory is unable to find the parasite in your stool sample, you doctor may choose to treat you based on your symptoms.

How is it treated?

There are several prescription medicines which can be used to treat giardiasis. Children are usually treated with a different medicine than adults.

How can you keep from getting it?

• Don't drink untreated water (streams, lake, etc). Boiling the water is the safest way. Chlorine and iodine are not always adequate to kill Giardia in stream water. Water filters which remove extremely small particles can also eliminate Giardia, and can be purchased at stores which sell camping supplies.
• WASH YOUR HANDS: 
  • before eating and before preparing food.
  • after changing diapers.
  • after emptying the cat litter box.
• Keep children away from animal droppings.

How can you keep from spreading Giardia if you have it?

WASH YOUR HANDS--after going to the bathroom and before fixing food or wiping children's faces. Persons who are ill with diarrhea should not prepare food for others. People whose job involves food preparation outside the home should not return to work until their doctor tells them it's okay.

Produced by: Communicable Disease Epidemiology Program (303) 692-2700 Colorado Department of Public Health and Environment June, 2001