Type: Parasitic

Geography: Europe, United States, Sub-Saharan Africa

Cases Per Year: 45 million

Fatality Rate: 0.1%

First Discovered: 1907 by Ernest Edward Tyzzer in the United States

Cryptosporidiosis is caused by the microscopic parasite Cryptosporidium. Many species of the parasite infect animals and some also infect humans. It is one of the most common waterborne diseases worldwide.

Symptoms generally begin 2 to 10 days after becoming infected. The most common symptom is watery diarrhea, in addition to stomach cramps or pain, dehydration, nausea, vomiting, fever, and weight loss. Symptoms usually last for 1 to 2 weeks in people with healthy immune systems, though symptoms can be present for up to 30 days. The small intestine is the site most commonly affected but it can also affect other areas in the digestive or respiratory tract. People with weakened immune systems may develop serious, chronic, and sometimes fatal illness. It mainly affects children under 5 years old.

Photo: Cryptosporidium parvum – Micrograph.