Giardiasis fact sheet

Giardiasis infection is not a notifiable disease.

Giardiasis is an infection of the bowel caused by the parasite, Giardia duodenalis.

What are the symptoms?

Symptoms include stomach cramps, excessive gas or bloating, frequent loose or pale, greasy stools, fatigue and weight loss. Fever and bloody diarrhoea are not usually seen with giardia infections. Many infected people have no symptoms.

The infection is diagnosed by examining the faeces under a microscope.

Incubation period: 3-25 days or longer (usually 7-10 days).

How is it spread?

Spread takes place when hands, objects or food become contaminated with the faeces of infected people or animals. The parasites are then taken in by mouth.

Infection may also result from drinking water contaminated by infected humans or animals. In institutions and preschool centres, person-to-person transmission may be a significant means of spreading the illness.

Infectious period:  For as long as the organism is present in the faeces (often months), whether or not the person is ill.

A person with diarrhoea is more likely to spread infection than a well person. However, a well person is still potentially infectious to others.

How is it prevented?

• Exclude from child care, preschool, school or work until diarrhoea has stopped.
• Follow good hand washing and keeping areas clean procedures.
• Water suspected of contamination should be boiled before drinking.
• Treatment of infected people reduces spread.

How is it treated?

Treatment of an ill person with appropriate antibiotic medication relieves symptoms and usually makes the person non-infectious within a few days.

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