You've Got What?
How infectious diseases are spread and simple and practical advice for preventing the spread of infection in the home and community
Giardia infection is an infection of the bowel caused by the parasite Giardia duodenalis, also known as Giardia lamblia or Giardia intestinalis. This parasite is a single-celled organism and is found worldwide. Although it occurs in many animals including dogs, cats, sheep and cattle, there is still some uncertainty about the extent of disease transmission between people and animals.
Spread takes place when hands, objects or food become contaminated with faeces of infected people or animals, or by drinking contaminated water. The parasites must be taken in by mouth to cause infection. In institutions and preschool centres, person-to-person transmission may be a significant means of spreading the illness. Transmission can occur with some sexual practices where there is contact with faecal matter. Re-infection can occur.
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 or by detecting Giardia in a faecal specimen using a PCR (polymerase chain reaction) test in a pathology laboratory.
(time between becoming infected and developing symptoms)
3 to 25 days or longer (usually seven to 10 days).
(time during which an infected person can infect others)
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, but a person without symptoms is still potentially infectious to others.
Treatment of an ill person with appropriate antibiotic medication relieves symptoms and usually makes the person non-infectious within a few days.