Outbreaks are usually associated with food or water contaminated with feces.
It can be asymptomatic in people with healthy immune systems, or symptoms can include watery diarrhea, nausea, cramps, and fever. Cryptosporidium parvum is transmitted in water. Cryptosporidium parvum is often transmitted by contact with human feces that contain infectious cysts, for example through poor handwashing.Multiple stool samples are often necessary for diagnosis. It can also produce watery diarrhea, foul-smelling stools, nausea, stomach cramps, bloating, gas, fatigue, and weight loss.
Giardia can result in asymptomatic intestinal infection. It can take up to three weeks before symptoms of giardia appear. It is transmitted through water, food, and contact with feces, often due to poor hygiene and handwashing.