Giardia transmission is typically via which route?

• A. Through fleas
• B. By airborne transmission
• C. Through direct contact with soil
• D. Usually picked up from drinking contaminated water

Answer: (D)

Giardia infection is most often acquired by swallowing cysts that come from water contaminated with fecal material. The cysts shed by an infected host can persist in streams, lakes, wells, and even poorly treated drinking water, and they resist some disinfection methods, so people can contract the parasite by drinking untreated water or water that hasn’t been properly treated, or by swallowing water during recreational activities. Fleas aren’t a vector for Giardia, and airborne spread isn’t how it’s transmitted. While contaminated soil can carry cysts, infection occurs when those cysts are ingested, not merely from contact with soil. So the usual route is drinking contaminated water.