Giardiasis

Giardiasis is an intestinal infection caused by the parasite Giardia, spread through contaminated water or food. It is one of the most common causes of parasitic diarrhoeal illness worldwide.

• Watery diarrhoea, often foul-smelling
• Abdominal cramps and bloating
• Excess gas
• Nausea
• Fatigue and, with prolonged infection, weight loss
• Some infections cause no symptoms at all

• Caused by the parasite Giardia, spread through the faecal-oral route via water or food contaminated with the parasite's cysts.
• Common sources include untreated drinking water, contaminated recreational water, and person-to-person spread in settings with close contact and limited sanitation.
• Risk is increased by unsafe water supply and poor sanitation.

• Diagnosed through stool microscopy identifying the parasite, sometimes requiring more than one stool sample as the parasite can be shed intermittently.
• Stool antigen testing, where available, improves diagnostic accuracy.

Treated with an oral antiparasitic medicine, commonly metronidazole or tinidazole, for a short course.

Adequate rehydration with oral fluids is important, particularly with significant diarrhoea.

Symptoms usually resolve within a few days of starting treatment, though some people experience prolonged digestive symptoms even after the infection has cleared.

Household members with similar symptoms should also be evaluated, as giardiasis can spread within households sharing water sources or close contact.

• Drink water from safe sources, or boil or treat water before drinking, especially when travelling or in areas with uncertain water quality.
• Wash hands thoroughly after using the toilet and before preparing or eating food.
• Avoid swallowing water while swimming in lakes, rivers, or pools.
• Wash fruits and vegetables thoroughly before eating.