Giardiasis and amebiasis: understanding the difference

Both infections can follow exposure to contaminated food or water and may cause diarrhoea, abdominal pain, bloating, nausea, tiredness, or reduced appetite. Giardia commonly affects digestion in the small intestine and may cause gas and greasy-smelling stools. Amebiasis can affect the bowel in a different way and may cause blood or mucus in stool and more marked abdominal symptoms. Symptoms overlap, and travel history alone cannot identify the organism. Laboratory examination of stool, sometimes using more than one sample, may be needed.

Arrange a GP consultation if diarrhoea persists, returns, or follows travel, untreated water, or a household exposure. Drink regularly and use oral rehydration solution when fluid loss is substantial. Wash hands with soap and water, clean shared bathroom surfaces, and avoid preparing food for others while diarrhoea continues. Do not use leftover antibiotics or someone else's medicine: treatment differs between parasites, and some medicines require a clinician to consider the bowel and any illness outside it.

Seek urgent medical care for blood in stool, severe or localised abdominal pain, repeated vomiting, fainting, confusion, very little urine, or profound weakness. Prompt assessment is also sensible for a child, older adult, pregnant person, or anyone with reduced immunity. Tell the clinician if symptoms began after travel or if more than one person became ill.

Ask which stool tests are appropriate, whether the result distinguishes giardia from amebiasis, whether household precautions are needed, and what treatment will target the identified parasite. Mention stool appearance, pain location, fever, medicines, travel, water sources, and symptom duration.