The kidney is subject to parasitic affections as well as other parts, although less liable to be thus affected than the liver. The most common parasite of the kidney is the echinococcus. It is the undeveloped embryo of the tapeworm. The sac in which the parasite is contained frequently attains the size of a child's head. Another parasite of the kidney is the strongylus gigas, a worm which somewhat resembles the round worm found in the intestines. It grows from six inches to three feet long.

The symptoms of parasites in the kidneys and their causes are both very obscure.