Giardiasis (Giardia lamblia)

Clinical criteria
Any person with at least one of the following four:
- Diarrhoea
- Abdominal pain
- Bloating
- Signs of malabsorption (e.g. steatorrhoea, weight loss)

Laboratory criteria
At least one of the following two:
- Demonstration of Giardia lamblia cysts or trophozoites in stool, duodenal fluid or small-bowel biopsy
- Demonstration of Giardia lamblia antigen in stool, duodenal fluid or small-bowel biopsy
- Detection of Giardia lamblia nucleic acid in stool, duodenal fluid or small-bowel biopsy

Epidemiological criteria
At least one of the following two:
- Human to human transmission
- Exposure to a common source

Case classification
A. Possible case
NA
B. Probable case
Any person meeting the clinical criteria and with an epidemiological link
C. Confirmed case
Any person meeting the clinical and the laboratory criteria

Current as of: 22 January 2019

Historic Case Definitions