Last Updated on January 5, 2024
What is Giardia?
Giardia lamblia is a parasite that can be found in contaminated water, contaminated food, and surfaces contaminated with feces from an infected person. It causes the diarrheal disease known as giardiasis. Giardia can be found in every region around the world.
Preventing the Spread of Giardia
Giardia can spread by the following means 
:
- Swallowing food or water contaminated with Giardia
- Having close contact with someone who is infected, particularly in childcare settings
- Traveling to areas with poor sanitation
- Exposure to poop through sexual contact with someone sick with Giardia
- Transferring Giardia germs from contaminated surfaces into your mouth (from bathroom handles, changing tables, diaper pails, or toys)
- Having contact with infected animals or animal environments contaminated with poop
Regular hand hygiene and surface disinfection are important preventative measures. Since this parasite can be found in contaminated water, proper water purification is a vital component in preventing the spread of Giardia. Since household wells can be a source of Giardia infection, they should be tested regularly and properly maintained. Pools and other recreational water sources should be properly disinfected. This parasite can also be spread through food — either due to poor hand hygiene of food handlers or because raw produce is irrigated or washed with contaminated water. Wash all fruits and vegetables well under running water and cook meat thoroughly .
Get Additional Protection with Germicidal UV Disinfection
In addition to the above preventative measures, Germicidal Ultraviolet (UV-C) surface disinfection (at the dosage listed below) can inactivate the Giardia in many applications. Our products use STER-L-RAY® Germicidal UV-C Lamps producing ultraviolet wavelengths at 254 nanometers, the region of germicidal effectiveness most destructive to harmful microorganisms including Giardia.
Germicidal Ultraviolet (UV-C) Water Purification can inactivate Giardia in drinking water or water used for food preparation. View our application page on Well Water Contamination for more information on how UV purification can help protect your well water against Giardia and many other harmful microorganisms. Germicidal UV Disinfection can be used to protect pools and other recreational water sources from various pathogens . UV-C disinfection will also inactivate this parasite on surfaces that could be contaminated. Another benefit of installing UV water purifiers is the ability to operate as usual during a boil water alert.
Giardia: Classification & Germicidal UV Dose for Inactivation
| Organism: | Alternate Name: | Type: | Disease: | UV Dose*: |
|---|---|---|---|---|
| Giardia Lamblia | Giardia | Parasite | Giardiasis | 100 mJ/cm2 |
Where is it found?
What can it infect?
How does it spread?
People at High Risk for Contracting an Infection
While anyone can contract a Giardia infection, certain people are at high risk :
- People in childcare settings
- People who are in close contact with someone who is infected
- Travelers to areas with poor sanitation
- People who have contact with poop during sexual activity
- Backpackers or campers who drink untreated water from springs, lakes, or rivers
- Swimmers who swallow water from swimming pools, hot tubs, splash pads, or untreated recreational water from springs, lakes, or rivers
- People who get their household water from a shallow well
- People with weakened immune systems
- People who have contact with infected animals or animal environments contaminated with poop
Giardia Symptoms:
Giardiasis is an intestinal disease that can show itself with the following short-term symptoms that can last from 2 to 6 weeks:
- Diarrhea
- Gas
- Foul-smelling, greasy poop that tends to float
- Stomach cramps or pain
- Upset stomach or nausea
- Vomiting
- Dehydration (loss of fluids)
Other, less common symptoms include fever, itchy skin, hives, and swelling of the eyes and joints. Occasionally, Giardia can cause long-term complications such as reactive arthritis, irritable bowel syndrome, and recurring diarrhea that can last for years. Among children in particular, severe giardiasis may delay physical and mental growth, slow development, and cause malnutrition.
Sources on Giardia:
The above information can be found on the following pages. Please read complete articles to learn more.
- CDC: Parasites – Giardia
- Mayo Clinic: Giardia Infection (Giardiasis)
- CDC Yellow Book, Chapter 2: Preparing International Travelers
- CDC: Four Steps to Food Safety: Clean, Separate, Cook, Chill
- CDC: Stay Safe and Healthy in Your Backyard Pool
* Nominal germicidal UV dosage necessary to inactivate better than 99% of microorganism.
- James E. Cruver, Ph.D., “Spotlight on Ultraviolet Disinfection”, Water Technology, June 1984
Learn More & Shop Our Products to Inactivate Giardia
Made in the USA from U.S. and imported parts, the UV Air & Surface Disinfection and UV Water Purification product lines from Atlantic Ultraviolet Corporation® are constructed of the highest quality materials and use germicidal UV-C lamps to disinfect air, surfaces, and water, inactivating microorganisms like Giardia.
Learn Here! Ultraviolet.com
- Download UV-C Air & Surface Documents from our PDF Library
- View all our Blog Posts for UV-C Air & Surface Disinfection
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- View all the applications that can benefit from Germicidal UV-C
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View our Infographic on Giardia
