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.
Causes. Infectious diseases can be caused by: Bacteria. These one-cell organisms are responsible for illnesses such as strep throat, urinary tract infections and tuberculosis. Viruses. Even smaller than bacteria, viruses cause a multitude of diseases â ranging from the common cold to AIDS. Fungi. Many skin diseases, such as ringworm and athlete's foot, are caused by fungi. Other types of fungi can infect your lungs or nervous system. Parasites. Malaria is caused by a tiny parasite that is transmitted by a mosquito bite.