Last year I saw a patient who had returned from her Christmas vacation complaining of persistent dizziness and fatigue that had not improved for over a year.

Before visiting my office she had consulted three other doctors but no cause for the dizziness was found.

When I questioned her about the vacation, which took place at a Caribbean resort, I discovered that she had experienced a transient episode of diarrhea there and since returning home had been unusually constipated and gassy.

She had never mentioned these intestinal symptoms to a doctor before, because it was dizziness and fatigue that bothered her the most.

I've seen many patients with chronic fatigue caused by intestinal parasites, so I had this woman tested at a specialized laboratory. The test revealed infection with a parasite called Giardia lamblia, a condition called giardiasis.

Read