Giardia is a microscopic parasitic organism called giardia lamblia. This organism is found throughout the world, and is a common cause of water-borne illness. The CDC states that it’s one of the most common pathogenic parasitic infections of humans worldwide. In 2013, 280 million people were infected with symptomatic giardiasis (the clinical name for the illness) around the world, and many more were carrying the illness without having symptoms.
Giardia is carried in the intestinal tracts of warm-blooded animals, as well as by humans. There are two stages to the infection, The trophozite stage, which is fragile and dies if it’s excreted, and the cyst stage, when the parasite creates a protective coating in order to survive and move in the environment to it’s next host. This is when giardia is able to thrive in multiple environments, including soil and water, and can even live in cold water for up to three months. This coating protects the cyst from many environmental factors, and also gives it a high resistance to chlorine disinfection.
Just as with E.Coli and other well-water microbes, giardia in well water can come from heavy rains, flooding, or any type of event that overwhelms a well with surface water. Well construction plays a key role in preventing microbes such as giardia from entering your well, however, even the newest, best-constructed wells can allow giardia and other microbes to flourish in your well. For more information about giardia lamblia and how it works, please click here to visit the CDC website listing.