Giardiasis
Giardiasis (also known as beaver fever) is a disease caused by the flagellate protozoan Giardia lamblia (also Giardia intestinalis). The giardia organism inhabits the digestive tract of a wide variety of domestic and wild animal species as well as humans. It is a common cause of gastroenteritis in humans, infecting approximately 200 million people worldwide.
Giardiasis is passed via the fecal-oral route. Primary routes are personal contact and contaminated water and food. People who spend time in institutional or day-care environments are more susceptible, as are travelers and those who consume improperly treated water. It is a particular danger to people hiking or backpacking in wilderness areas worldwide. Giardia is suspected to be zoonotic—communicable between animals and humans. Major reservoir hosts would include beavers, dogs, cats, horses, and cattle.