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What Is Giardia?

Giardia lamblia is a common waterborne parasite that causes the diarrheal illness giardiasis. Humans most often come into contact with Giardia in water by swimming in contaminated pools. However, it can also be transmitted through other sources that have been exposed to stool from an infected person or animal. The water parasite Giardia infects living things by being swallowed or transmitted through blood. Trace amounts of this pathogen can even be found in tap water, so it is crucial to implement prevention and mitigation strategies for Giardia in your water supply.

Understanding Giardiasis

Giardiasis is the illness caused by ingesting Giardia in drinking water or another source. More than 15,000 cases of this disease are reported in the United States every year. Although the symptoms are analogous to the stomach flu, they can last longer —from two to six weeks, depending on the severity of the infection. People diagnosed with giardiasis typically report cramping, diarrhea, nausea, and other gastrointestinal ailments.

Guarding Against Giardia

One of the most challenging things about protecting against Giardia is that the cysts can cause infection even at low concentrations within a water supply. This means it can require testing several gallons of water, and, even then, the cysts still may not be detected.

In most cases, testing for thermotolerant E. Coli is recommended because if it is not present, there is a high probability that Giardia will not be present, either. This, combined with the cysts’ resistance to chlorine, means that prevention is the best strategy overall.

Giardia water treatment is important because the parasite is highly resistant to chlorine and other common disinfectants used to treat water sources shared by large groups of people. Multiple safeguards are necessary to guard the public and employees from this danger when they’re on your property. LiquiTech is a leader in providing Giardia water tests and disinfection solutions that can be combined for near-total protection. With our point-of-entry filtration and ultraviolet lamp technologies, property owners can enjoy the security of multiple lines of defense.

LiquiTech’s SAFETGUARD®self-cleaning filter system removes sediment and corrosion as well as biofilm deposits at the source. This means biological pathogens are deprived of the nutrients and environment they need to flourish. SAFETGUARD® requires no consumables and works within seconds of installation. It provides a high-efficiency, low-waste barrier against infection.

SAFETGUARD® can be coupled with our advanced UV lamp systems to add an extra layer of security to your plumbing. Exposing water to high-intensity UV light damages the DNA and RNA of any bacteria, viruses, molds, or yeasts within it. These unwanted intruders will be rendered inert and unable to reproduce. The proprietary design of our lamps gives the most reliable and efficient performance possible. When our filter system and UV lamps are combined, they offer a superior level of protection against giardiasis and many other waterborne diseases.

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How is it Spread?

Giardia lamblia is a waterborne parasite that lives in the intestine of infected humans or animals. You can become infected after accidentally swallowing the parasite or via contact with blood.

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Over 15,000 Documented Cases Each Year in the U.S.

SYMPTOMS: Symptoms of giardiasis may last anywhere between two and six weeks and include diarrhea, stomach cramps, nausea, and other intestinal symptoms.

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Giardia Levels Range From 10,000 to 100,000 CYSTS/L in Untreated Sewage, 10 to 100 CYSTS in Treated Sewage, And 10 Or Fewer CYSTS/L in Tap Water

Giardia is passed in the stool of an infected person, and may also be present in soil, food, and water. It is commonly transmitted in swimming pools or from swallowing water that has come in contact with the feces of a person or animal infected with Giardia.

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Giardia have been proven to be extremely resistant to oxidant treatments such as chlorine.

States with Incidence Higher than 10 Cases per 100,000 Population of Giardiasis

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This map represents the rate of instance annually as reported to the National Notifiable Diseases Surveillance System.


The EPA recommends filtration and UV disinfection for controlling and preventing Giardia in water systems.

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