An infection of the intestines that is caused by a parasite.
Giardia infection is caused by a parasite that is found worldwide and is too small to be seen. The most common way to become infected is to swallow contaminated water.
Giardia symptoms can include stomach cramps, bloating, upset stomach, fatigue, weight loss, gas and bouts of watery diarrhea. But some people infected with giardia never get symptoms.
Severe or long-lasting giardia infection is treated with antibiotic medicine. Often people get better on their own without any medicine.