Giardiasis
Giardiasis is a bowel infection caused by the parasite Giardia lamblia (also known as Giardia intestinatis).
How it spreads
Person to person spread occurs by eating food that has been contaminated by faeces from an infected person.
Spread may also occur by ingesting Giardia from:
- recreational water
- drinking water or
- food contaminated by animal or human faeces.
Giardia is not present in household drinking water in the Northern Territory.
Who is at risk
Children are infected more frequently than adults.
Those at risk of giardiasis include:
- children who attend childcare due to faecal contamination of toys or food
- people who drink unfiltered surface water (e.g. from creeks or billabongs)
- people who swim in bodies of freshwater
- travellers to developing countries or remote communities where sanitation and hygiene standards are poor.
Symptoms
The symptoms develop between 3 to 25 days or longer after infection, most commonly 7 to 10 days.
Symptoms of giardiasis include:
- sudden onset of diarrhoea
- foul smelling, pale, greasy stools (bowel action)
- stomach pains
- bloating
- loss of appetite
- nausea
- fatigue
- weight loss
- poor weight gain in infants.
Some infected people may have no symptoms at all.
Infectious period
While the Giardia parasite remains in their faeces, infected people can pass the infection on to others.
This can be for many months.
Some people may ‘carry’ the parasite in their bowel after the symptoms have resolved or they may not have had any symptoms at all.
Diagnosis
The diagnosis of Giardia is confirmed by testing stools in the laboratory.
Treatment
Anyone with symptoms of giardiasis should be seen by a doctor.
Antibiotics such as tinidazole or metronidazole may be prescribed for treatment.
If you are vomiting or have diarrhoea, you should drink extra fluids to avoid dehydration.
Rehydration therapy with oral glucose / electrolyte solution is particularly effective.
If children refuse this solution, diluted fruit juice may be given (1 part juice to 4 parts water).
Babies should continue to be offered their normal feeds plus extra fluids in between feeds.
Medicines to prevent vomiting or diarrhoea should not be given, especially to children, except when prescribed by a doctor.
When to see a doctor
Children who refuse extra fluids should see a doctor.
Additionally, anyone with the following should also see a doctor:
- prolonged (>3 days) or severe diarrhoea
- blood in their stools
- people concerned about their symptoms.
Control measures
People with vomiting or diarrhoea should not:
- prepare or handle food that will be eaten by others
- go back to work, school or childcare until 48 hours after diarrhoea and vomiting have ceased
- swim, wade or paddle in public pools.
Doctors and public health workers are interested in preventing outbreaks of diarrhoea.
If there are 2 or more cases in a group, these should be reported to the local Centre for Disease Control.
Prevention
Good hygiene practices are the best way to prevent giardiasis.
These practices include:
- washing hands thoroughly with warm soapy water:
- after going to the toilet
- before preparing or handling food
- after every nappy change
- after changing soiled linen
- never changing nappies on tables or counters where food is prepared or eaten
- cleaning change areas with warm soapy water and disinfectant after every nappy change
- not drinking untreated water
- cleaning books, toys, equipment, furnishings, floors and toilets regularly (including toilet door handles)
- washing and/or peeling fruit and vegetables before eating them
- frequently emptying of wading pools - they should be cleaned and left to dry and not be used by children who have diarrhoea.
Information for health professionals
To find out more, go to the NT Health website.
Contact
Contact your nearest Centre for Disease Control on the NT Health website.