UV Lights Effect on Animal Giardia

Several pathogenic (disease-causing) protozoa are particularly problematic in water supplies. One example is giardia, which is not an animal but a genus of the protista kingdom of the eukaryotic domain. The species of giardia that typically acts as a parasite in humans is giardia lambda. Fortunately, ultraviolet (UV) radiation has proven effective in destroying giardia that contaminate fresh water supplies around the world.

Uniqueness of Giardia

Giardia are present in certain fresh water sources

Although members of the eukaryotic domain of life, which is characterized by cells that contain membrane-bound organelles, giardia are one of a handful of eukaryotic genera that do not have mitochondria. This may or may not contribute to their vulnerability to UV light.

Lifecycle of Giardia

Diagnosis of Giardia infection require laboratory testing of stool samples

Normally, giardia exist as free cells in water. As is the case with many protists, when the environment becomes harsh, giardia cells can convert to a cyst form (oocysts). Oocysts are resistant to various water treatments including chlorination. When cysts are ingested, giardia can become parasites within humans, causing enteritis characterized by diarrhea and gas. Diagnosis can be confirmed with the detection of oocysts in stool samples.

Ultraviolet Light

Tap water supplies can be protected with equipment that treats the water with UV radiation

During the first decade of the 21st century, studies revealed that UV radiation of certain wavelengths was useful in killing oocysts of both giardia and another parasitic protist known as cryptosporidium. In 2010, researchers at Tel Aviv University announced the development of a device that integrates into tap water systems, treating the water with the optimal anti-parasitic UV wavelength.

References

• Red Orbit: Ultra-violet Light Can Purify Water
• W.A.M. HijnenCorresponding Author Contact Information, E-mail The Corresponding Author, E.F. Beerendonk and G.J. Medema. Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: A review. Water Research Volume 40, Issue 1, January 2006, Pages 3-22