Giardia food poisoning is caused by a parasite known as Giardia lamblia or Giardia intestinalis. Giardia is also a common cause of waterborne disease in the United States.
Symptoms of Giardia infection, or Giardiasis, may include stomach cramps, diarrhea, gas, belching, bloating, greasy stools, nausea or upset stomach. Symptoms may occur 1 to 2 weeks after infection, and usually last from 1 to 3 weeks. Weight loss and dehydration may also occur as a result of these symptoms. Some individuals with Giardiasis are asymptomatic, meaning that they do not exhibit symptoms.
Giardia infection occurs when an individual eats food, drinks water, or comes into contact with surfaces or objects contaminated by the parasite or its cysts (a dormant stage in which the parasite is resistant to many adverse environmental conditions allowing it to survive outside the body).