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What signs and symptoms does giardiasis cause?
The most common manifestations of giardiasis are diarrhea and abdominal pain, particularly cramping; however, diarrhea is not invariable and occurs in 60% to 90% of patients. Other common manifestations include:
Fever is unusual. The severity of the symptoms may vary greatly from mild or no symptoms to severe symptoms. Stools may be foul smelling when the Giardia interferes with the absorption of fat from the intestine (malabsorption). The illness or the malabsorption may cause loss of weight.
Symptoms and signs of giardiasis do not begin for at least seven days following infection, but can occur as long as three or more weeks later. In most patients the illness is self-limiting and lasts 2-4 weeks. In many patients who are not treated, however, infection can last for several months to years with continuing symptoms. Children with chronic infection may fail to thrive. Some patients recover from their giardiasis, with or without treatment, but symptoms continue, perhaps because of a condition referred to as postinfectious irritable bowel syndrome. The cause of the continuing symptoms is not clear but may be due to bacterial overgrowth of the small intestine.