Polycystic kidney disease can cause abdominal pain, headaches, and pain in the sides and back. Porphyria is a condition that can affect the nerves and skin, making the skin extremely sensitive to sunlight. Hydronephrosis is a condition of the kidneys and causes aching or pain, urinary symptoms, fever, and nausea.
Protozoan infections are parasitic diseases caused by organisms formerly classified in the Kingdom Protozoa. They include organisms classified in Amoebozoa, Excavata, and Chromalveolata. Examples include Entamoeba histolytica, Plasmodium (some of which cause malaria), and Giardia lamblia. Trypanosoma brucei, transmitted by the tsetse fly and the cause of African sleeping sickness, is another example.
Cyclospora cayetanensis. Cyclospora cayetanensis is a protozoan that causes disease in humans, and perhaps primates. It has been linked in the United States to fecally contaminated imported produce, and was virtually unknown before about 1990, but has been on the rise since.