Transmission
Giardiasis is passed via the fecal-oral route. Primary routes are personal contact and contaminated consumables. The more susceptible are institutional or day-care workers, travelers, those eating improperly treated food or drink, and people who have contact with individuals already infected.
It is a particular danger to people hiking or backpacking in wilderness areas worldwide, especially if they have no immediate access to medical supplies. Giardia is also suspected to be zoonotic—communicable between humans and other animals. Major reservoir hosts include beavers, dogs, cats, horses, humans, cattle and birds.
Read more about this topic: Giardiasis