Giardiasis: Risk, Symptoms, Treatment & Prevention

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You don’t want Giardiasis otherwise known as Beaver Fever ruining your hiking, kayaking, canoeing, or camping fun.

Giardiasis is a diarrheal disease caused by the Giardia parasite, a microscopic organism that feeds off its host. The parasite thrives in the intestines of the infected host and is passed in bowel movements. Once outside the host, it can spread by contact or ingestion of contaminated food or water.1

Let’s look at how you can avoid this diarrheal disease and what to do if you or someone you know become infected with the Giardia parasite.

How Is Giardiasis Spread?

Giardiasis is spread through the poop of an animal or human.

Let’s get totally real! The host with Giardiasis has some nasty squirts filled with millions of giardia parasites and if you come in contact with one of these parasites you can become infected too! Here’s how…

You can acquire Giardiasis by:

  • Swallowing water while swimming, playing, tubing, or boating in lakes, rivers, springs, ponds, or streams.
  • Getting water in your nasal passages while swimming, playing, or boating in lakes, ponds, rivers, springs, or streams.
  • Drinking water or using ice contaminated with Giardia.
  • Swallowing Giardia picked up from contact with bathroom surfaces.
  • Eating uncooked food contaminated with Giardia.

Symptoms of Giardiasis

A Giardia infection can cause great intestinal discomfort yet some people may have no symptoms at all.

Symptoms of Giardiasis normally begin 1 to 3 weeks after being infected and may include:1,2,3

  • Diarrhea
  • Nausea
  • Vomiting
  • Gas
  • Abdominal cramping
  • Greasy looking stools
  • Dehydration

If you’re experiencing these symptoms on a longer outdoor adventure like backpacking, trekking, or camping, it would be safer to cut your trip short. Discomfort and pain aside, the dehydration and weakness you’ll experience will make for unsafe situations if you continue.

If you think you have Giardia, visit your healthcare provider.

Who Is at Greatest Risk of Getting Giardiasis?

A man relaxing in a stagnant pool of water with giardia risks contracting giardiasis.

Some people are at greater risk of coming in contact with the Giardia parasite than others.

In the United States, Giardiasis is most often seen in those who enjoy outdoor adventures, daycare workers, and international travelers.4

  • Backpackers, hikers, kayakers, canoers, and campers who drink contaminated water.
  • Backpackers, hikers, kayakers, canoers, and campers who do not practice good hygiene like handwashing.
  • People who swim, play, tube, kayak, canoe, or boat in lakes, ponds, rivers, springs, or streams.
  • People living with someone who has giardiasis. This includes sharing a campground, campsite, tent, bathroom, outhouse, etc.
  • Any caregiver who looks after someone sick with Giardiasis.
  • Daycare workers and children in childcare, especially those in contact with diaper-aged children.
  • Travelers who go to a country where giardiasis is common.
  • People who have contact with animals with a Giardia infection… The risk of acquiring Giardia from a dog or cat is low. There are different types of Giardia. The type that infects humans is usually different than the type found in cats and dogs.
  • Anyone having sex, especially anal sex, with someone infected with Giardia.

Treatment of Giardiasis

Over-the-counter medication used to treat giardiasis symptoms.

To determine if you’re infected, your doctor will have your stool tested by a laboratory for parasites.

Symptoms of Giardiasis usually last 2 to 6 weeks in healthy adults though antibiotics may help reduce this timespan. Common antibiotics used for treatment are:3,5,6,7

  • Metronidazole (Flagyl)
  • Tinidazole (Tindamax)
  • Nitazoxanide (Alinia)

If your condition is persistent, stool tests may be used for monitoring the effectiveness of the medication being used to treat the infection.

Only use Imodium or Pepto-Bismol as and if directed by your doctor. You want to kill off the Giardia parasites with antibiotics and/or poop out not keep active parasites in your system.

Prevention of Giardiasis

Prevent it. Don’t get it.

To prevent Giardiasis and keep others from contracting Giardia…8,9

  • Practice good hygiene like washing your hands.
  • Avoid drinking water that may be contaminated.
  • Purify questionable water before drinking.
  • Avoid recreational activities in water that may be contaminated.
  • Don’t eat food that may be contaminated.
  • Cook food thoroughly.
  • If cooking with water, purify questionable water before use.
  • Wash or peel your raw fruits and vegetables before eating.
  • Don’t have sex (especially anal sex) with someone who has or is suspected of having Giardia.10

Water Purification

Common methods for purifying water are to bring water to a rolling boil for one minute, use a water filter, or treat it with iodine, chlorine, or ultraviolet (UV) light.8

Some purification methods are better than others and some are better for your particular outdoor adventure.


I love to canoe and kayak! I’ve been on some really nasty rivers and streams. On numerous occasions, I’ve accidentally swallowed water from these waterways and gotten it in my nasal cavities. I’ve yet to get sick, but it’s been disconcerting at times.

I figure it’s only a matter of time before I get sick from Giardia or some other parasite. It’s why I wanted to include this article. We all need to know about these dangers and especially what to do if we get sick.

This article in no way constitutes medical advice. See a doctor if you think you might have Giardia or another parasite.

Stay safe and have a blast out there!

Man diving into a lake. The text says... Giardiasis Parasitic Infection. Who is at Greatest Risk?


  1. Parasites – Giardia: General Information. Centers for Disease Control and Prevention.
  2. L.J. Robertson, K. Hanevik, A.A. Escobedo, K. Morch, and N. Langeland. Giardiasis–Why Wo the Symptoms Sometimes Never Stop? Trends Parasitol. 2010;26(2):75-82.
  3. A.A. Escobedo and S. Cimerman. Giardiasis: a Pharmacotherapy Review. Expert Opin Pharmacother. 2007;8(12):1885-1902.
  4. Noel Dunn and Andrew L. Juergens. Giardiasis. StatPearls.
  5. Mayo Clinic Staff. Giardia infection (Giardiasis). Mayo Clinic.
  6. Timothy B. Gardner and David R. Hill. Treatment of Giardiasis. American Society for Microbiology: Clinical Microbiology Reviews. January 2001, 14 (1) 114-128.
  7. Parasites – Giardia: Treatment. Centers for Disease Control and Prevention.
  8. M.C. Erickson and Y.R. Ortega. Inactivation of Protozoan Parasites in Food, Water, and Environmental SystemsJournal of Food Protection. 2006;69:2786–808.
  9. Parasites – Giardia: Prevention & Control: General Public. Centers for Disease Control and Prevention.
  10. M.J. Schmerin, T.C. Jones, and H. Klein. Giardiasis: Association with HomosexualityAnnals of Internal Medicine. 1978 June;88(6):801-3.

OtterBee Outdoors is for entertainment purposes only and should not be considered medical advice, diagnosis, or treatment recommendations. Statements regarding dietary supplements and other statements on the site have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition. Please consult a physician to determine your best plan for treatment.

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