Giardia [gee-are-dee-ah] is another of those unwanted visitors that may plague people as well as their pets.

This microscopic parasite, found throughout the U.S., infects the intestinal tract. Infections occur after a person or an animal ingests giardia-contaminated materials — such as untreated water consumed while camping.

The hallmark of a giardia infection is diarrhea with a very foul odor. It can be a stubborn infection to knock out, despite the variety of treatments that have been used. Dogs and cats should be shampooed during treatment, because giardia cysts from their stool can contaminate fur and be ingested during grooming.

Analyzing a stool sample for giardia is an important part of your pet’s annual exam. Even then, giardia infections can sometimes be tough to diagnose because cysts may be shed intermittently.