Giardiasis: Symptoms, Transmission & Prevention for Canadians

Giardiasis is an intestinal infection caused by a microscopic parasite called Giardia intestinalis (also known as Giardia lamblia). The most common symptom is diarrhea, often accompanied by digestive discomfort. Although unpleasant, giardiasis is usually treatable and rarely dangerous with proper care.

Common Symptoms

Symptoms can include:

• Diarrhea

• Abdominal cramping

• Bloating or gas

• Nausea or upset stomach

• Fatigue or low energy

• Loss of appetite

• Weight loss (due to reduced nutrient absorption)

• Dehydration

Less common symptoms include vomiting and low-grade fever (37°C–38°C).

When to Seek Medical Assessment

A healthcare provider should be consulted if:

• Digestive symptoms last longer than one week

• There was recent international travel

• Symptoms interfere with eating, drinking, or routines

• There are signs of dehydration (dry mouth, dizziness, reduced urination)

For infants and young children, medical advice is recommended if diarrhea continues for more than 2–3 days, or if there are 6+ episodes in 24 hours.

Diagnosis often involves stool testing. Because detection can vary, several samples may be collected on different days.

Treatment

Giardiasis is typically treated with prescription medication, commonly an antibiotic such as metronidazole. Possible side effects may include nausea or mild dizziness.

Important considerations:

• Avoid alcohol during treatment and for 48 hours afterward, as interactions may worsen side effects

• Family members may be treated as a precaution if there is concern about household transmission

• Children and childcare settings may require clearance guidance depending on symptoms and local policies

How Giardiasis Spreads

Giardia can spread through:

• Drinking water contaminated with the parasite

• Direct contact with an infected person

• Handling diapers or assisting with toileting

• Food prepared without proper handwashing

• Foods rinsed in contaminated water

While giardiasis exists worldwide, risk is higher where water quality and sanitation are limited.

Who Is at Higher Risk?

Anyone can become infected, but the following groups may have greater exposure:

• Young children in childcare settings

• Parents and caregivers changing diapers

• International travellers

• Campers or hikers drinking untreated surface water

• Individuals in areas with limited sanitation

Prevention & Hygiene Measures

Helpful strategies include:

• Regular handwashing with soap and water

• Proper diaper changing practices

• Avoiding untreated drinking water during travel, camping, or hiking

• Ensuring food is washed with safe, potable water

Good hygiene remains an effective tool for protecting families and communities.

First Aid & Public Health Awareness in Canada

While giardiasis is not a first aid emergency, dehydration from diarrhea can become a concern — especially for young children, older adults, and travellers. First aid training through St. Mark James Training supports Canadians in recognizing signs of dehydration and knowing when to seek medical care. Many workplaces, camps, and childcare environments pair first aid with CPR/AED training to strengthen health and safety readiness.

Educational Disclaimer

This article provides general education for Canadians and is not a diagnostic tool. Consult your healthcare provider for persistent or worsening digestive symptoms, especially after travel. Seek medical attention for signs of dehydration.