Giardia Lamblia is Inactivated by Germicidal UV-C Light

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.

Where is it Found?

A bowl of spinach contaminated with Giardia — Contaminated Food

Diaper changing table — Contaminated Surfaces

Glass of water being filled from tap — Contaminated Water

What Does it Infect?

Woman in pain from gastrointestinal tract, showing through skin — Intestines

How Does it Spread?

Woman eating clams contaminated with Giardia — Eating Food

Hands changing a baby's diaper — Touching Surfaces

Woman drinking a glass of water — Drinking Water

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 sanitationopen_in_new
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 wellsopen_in_new can be a source of 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 foodopen_in_new — 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 thoroughlyopen_in_new.

Get More Protection with UV Disinfection

In addition to the above preventative measures, Germicidal Ultraviolet (UV-C) water disinfection can inactivate Giardia in well water, swimming pools and hot tubs, drinking water, and food prep water.

UV-C disinfection will also inactivate this parasite on surfaces that could be contaminated. UV water purifiers give the ability to operate normally during a boil water alert. Shop our products at AtlanticUltraviolet.comopen_in_new.

Learn about these applications:

View all UV-C Application Pages.

Our germicidal lamps produce ultraviolet wavelengths at 254 nanometers, the region of maximum germicidal effectiveness. Read our FAQ blog post to learn more. See dosage data below.

UV applications for water and surface disinfection of Giardia

Giardia: Classification & Germicidal UV Dose for Inactivation

Organism:	Alternate Name:	Type:	Disease:	*UV Dose:**
Giardia Lamblia	Giardia	Parasite	Giardiasis	100 mJ/cm²

* Nominal germicidal UV dosage necessary to inactivate better than 99% of microorganism.

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 sanitationopen_in_new
People who have contact with poop during sexual activity
Backpackers or campers who drink untreated water from springs, lakes, or riversopen_in_new
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.

Dosage Source

Sensitivity of Bacteria, Protozoa, Viruses, and Other Microorganisms to Ultraviolet Radiation. Journal of Research of the National Institute of Standards and Technology, Volume 126, Article No. 126021. August 20, 2021.

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Since 1963, we’ve been engineering and manufacturing germicidal ultraviolet equipment to neutralize harmful microorganisms in water, in air, and on surfaces. Visit these helpful pages:

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Giardia Lamblia is Inactivated by UV-C Light