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What is it?

Giardiasis is an infection of the upper small intestine caused by an organism called Giardia lamblia that occurs as cysts in the feces. It occurs worldwide and it affects children more often than adults. It is more common in areas of poor sanitation and institutions where children are not toilet trained, including day care centres. In Canada and the USA, it occurs more frequently from July to October in children under five and adults 25 to 39.

How is it spread?

Giardia lamblia is mainly spread by hand-to-mouth transfer of cysts from the feces of an infected person, particularly in day cares and institutions. It is also spread by ingesting contaminated water that hasn’t gone through a filtering system. Chlorine treatment does not destroy the G. lamblia organism. Having anal intercourse, swimming in contaminated water, eating contaminated food and having a child in day care are others ways that G. lamblia is spread.

What are the symptoms and when do they occur?

Symptoms appear three to 25 days or more (usually seven to 10 days) from the time of contact with the organism. Symptoms can include acute to chronic diarrhea, abdominal cramps, bloating, frequent loose and pale greasy stools, feeling tired, inability to absorb fats and fat-soluble vitamins, and weight loss. Symptoms and the degree of symptoms vary and some people may not have any symptoms.

When is it infectious?

A person is infectious for the entire time of the infection, often months.

How can I protect myself and prevent the spread?

To prevent spread to yourself and others the following measures should be practiced:

  • Practice thorough hand washing with soap and warm water especially before handling food, before eating, after using the toilet and after handling diapers from an infected person.
  • Filter (less than five micron filter) public water supplies exposed to fecal contamination. Boil water rapidly for one minute for emergency water use.
  • Do not prepare food for others if you are infected with G.lamblia.

Recommended Absence

Persons who are food handlers, persons who work in hospitals and other institutions where people live, or persons who attend day care centres should be absent while symptoms are present.

G. lamblia must be reported to the Medical Officer of Health as required by the Health Protection and Promotion Act.

For more information, please contact a member of Haldimand-Norfolk Health Unit’s Infectious Disease Team.

Simcoe Office: 519.426.6170 / 905.318.6623
Caledonia Office: 905.318.5367

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