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HealthInfo Canterbury


Giardia is a parasite (living thing) found in the gut of people, and animals such as cattle, sheep, cats and dogs. It's also found in infected water such as lakes and streams.

You can get giardia (or giardiasis) if you swallow contaminated water. This can cause an infection called gastroenteritis.

Symptoms usually start seven to 10 days after being infected and usually last between three and four days.

The symptoms include diarrhoea, stomach pain or cramp, feeling sick and vomiting, and a slight fever. Many people don't get any symptoms.

How is giardia treated?

Giardia is treated by a course of antibiotics such as metronidazole. You should also rest and drink plenty of fluids to prevent dehydration.

When and where should I seek help?

If you think you have giardia you should visit your GP.

You should see your GP if you have bloody diarrhoea or a fever, or if your symptoms haven't gone away after seven days. You should also see your GP if you're very unwell or if you have a weakened immune system.

You should take your child to your GP if they aren't drinking.

How can I avoid spreading giardia?

To reduce the risk of spreading the infection, it's important to have good hand hygiene. This includes washing your hands with soap and water, especially after using the toilet.

Try to avoid preparing food if you have giardia. If you do prepare food, make sure you wash and dry your hands well first. Follow this food safety advice.

Stay away from work, community gatherings and school or preschool until you or your child have been free of symptoms for 24 to 48 hours. This includes the last time you had diarrhoea.

You should wait for at least two weeks after the last episode of diarrhoea before you go swimming in a pool.

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Written by HealthInfo clinical advisers. Last reviewed June 2018.


See also:

About diarrhoea & vomiting (gastroenteritis)

Diarrhoea & vomiting in children

Page reference: 49689

Review key: HIGTE-81185