Protozoan

In the summer of 2007, 6 fatal cases of infection occurred in the United States, all young males (Medscape)

Giardiasis is not associated with mortality except in rare cases of extreme dehydration, primarily in infants or malnourished children (Medscape)

Case fatality rates associated with amebic colitis range from 1.9%-9.1% (Aristizábal et al, 1991)

Cryptosporidium parvum causes cryptosporidiosis, a parasitic infection. The symptoms of cryptosporidiosis are: watery diarrhea, stomach cramps, dehydration, nausea, vomiting, fever, and weight loss. In healthy people, the disease created by the parasite is self-limiting, but in immunosuppressed individuals, the disease may be chronic and severe.

C. hominis causes the disease, Cryptosporidiosis. The symptoms are: diarrhea, vomiting, anorexia, fever, and abdominal cramping. The respiratory system can be affected as well. It is usually self-limiting, but can be harmful to immunocompromised individuals.

This amoeba is rare, but it can cause severe infections of the eye, skin, and central nervous system. It can cause three major infections: acanthamoeba keratitis, GAE, and disseminated infection. Acanthamoeba keratitis is an infection in the eye that can cause permanent visual impairment in healthy people. GAE is a serious brain and spinal cord infection that occurs in immunocompromised individuals. Disseminated infection is a widespread infection that affects the skin, sinuses, lungs, and other organs, which is more common in immunocompromised individuals.