Giardia

Date of publication: September 2000

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Prevent this food and waterborne disease Giardia (pronounced gee-ah-dee-ah) is a parasite found in the gut of humans and animals such as cattle, sheep, cats, dogs, rats and possums. It is passed on in the faeces (poo, tutae) of infected animals and humans. Giardia is widespread in New Zealand and the parasites can live in the environment for long periods, especially in lake, river, stream and roof water. How does a person become infected? People become infected when they swallow the parasites. This may be from contaminated water and food, or from contact with infected animals or humans.

The signs and symptoms of the illness

Giardia may cause:

• foul smelling diarrhoea
  
• stomach cramps and abdominal pain
  
• nausea and vomiting
  
• weight loss
  
• bloating
  
• slight fever
  
• headache
  
• fatigue.
  

Symptoms appear between three and 25 days (usually seven to ten days) after becoming infected.

The person will usually be ill for three to four days and without treatment may remain infectious for months. During this time the person can spread the parasite to other people, even when there are no other symptoms.

Treatment of giardia infection

• For advice and testing you will need to visit your doctor.
  
• Take a faecal specimen with you, as a laboratory test will be needed.
  
• Your doctor will give you a course of drugs such as Flagyl or Dyzole.
  
• Drink plenty of safe fluids while the diarrhoea lasts, to prevent dehydration. Follow your doctor's instructions.
  
• Go back to your doctor if your child is not drinking.
  
• If you have giardia infection the doctor is required to report this to the Medical Officer of Health of the Public Health Service (PHS). The PHS may contact you to find out how you picked up the parasite. This helps to prevent more outbreaks of the illness.
  

Taking time off work or school

Usually people can go back to work and children can return to early childhood centres and school when the symptoms are gone.

However, as giardia infection is a notifiable disease you will need to check with your doctor or health protection officer first.

If you are working with food, or employed in a hospital, rest home, school or early childhood centre you may be required to stay away from work until you are tested free from giardia infection.


How to avoid getting giardia infection and passing it on to others

Washing hands

Wash your hands thoroughly by using plenty of soap, cleaning under fingernails, rinsing hands well and drying on a clean towel:

• before and after preparing food
  
• after going to the toilet or changing a baby’s nappy
  
• after caring for people with giardia
  
• after playing or working with animals.
  

It is best to avoid preparing food for other people if you have giardia infection but if you have to, wash your hands carefully.


Water in rural areas

• Drinking water taken from the roof, rivers, lakes etc. should be boiled for one minute or an approved filter (Standard AS/NZS4348:1995) should be used.
  
• When using roof water, spouting should be cleaned regularly and roofs kept clear of bird and animal droppings.
  
• Aoid placing TV aerials on the roof for birds to perch on and avoid planting trees close to the house to prevent animals from getting on to the roof.
  

When you visit a swiming pool:

• take your children to the toilet before they swim and then wash hands
  
• shower yourself and your children using soap (particularly in the area around the bottom) before entering the pool
  
• ensure babies swim in tight fitting togs, not nappies, to prevent faecal matter getting into the water. Wash your hands after changing the baby
  
• report any faecal accidents (poo in the water) to the pool attendant immediately.
  

No one should go swimming in a pool if they have diarrhoea. Wait until at least two weeks after the symptoms have gone.


Help keep the environment free of giardia when tramping and camping

• Use toilets when they are provided.

• When no toilets are provided bury toilet waste and paper. Make sure you bury it at least 50 metres away from any water source such as rivers and lakes.
  
• Do not wash your hands directly in the water. Collect water, wash your hands in it and then drain it into the ground away from the water source.
  

Washing hands in hot soapy water and drying them with a clean towel will help prevent the spread of giardia

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Document availability

You can also download the Giardia pamphlet in PDF format from the Ministry of Health's Health Education website.