Giardiasis (gee-ar-dye-a-sis) is an infection of the digestive system caused by tiny parasites called Giardia intestinalis (also known as Giardia lamblia, or Giardia duodenalis).
Diarrhoea is the most common symptom of giardiasis.
Other symptoms can include:
abdominal cramps
foul-smelling flatulence and belching
nausea (feeling sick)
bloating
indigestion
fatigue (extreme tiredness)
dehydration
loss of appetite
weight loss caused by malnutrition
medicines called metronidazole or tinidazole are used.