Symptoms

Some people with giardia infection never develop signs or symptoms, but they still carry the parasite and can spread it to others through their stool. For those who do get sick, signs and symptoms usually appear one to three weeks after exposure and may include:

• Watery, sometimes foul-smelling diarrhea that may alternate with soft, greasy stools
• Fatigue
• Stomach cramps and bloating
• Gas
• Nausea
• Weight loss

Signs and symptoms of giardia infection may last two to six weeks, but in some people they last longer or recur.

When to see a doctor

Call your doctor if you have loose stools, stomach cramping and bloating, and nausea lasting more than a week, or if you become dehydrated. Be sure to tell your doctor if you're at risk of giardia infection — that is, you have a child in child care, you've recently traveled to an area where the infection is common, or you've swallowed water from a lake or stream.