Dioctophyme renale, commonly referred to as the giant kidney worm, is a parasitic nematode (roundworm) whose mature form is found in the kidneys of mammals. D. renale is distributed worldwide, but is less common in Africa and Oceania. It affects fish eating mammals, particularly mink and dogs. Human infestation is rare, but results in kidney destruction, usually of one kidney and hence not fatal. A 2019 review listed a total of 37 known human cases of dioctophymiasis in 10 countries with the highest number (22) in China. Upon diagnosis through tissue sampling, the only treatment is surgical excision. Synonyms Dioctophymosis, dioctophymiasis, giant kidney worm, kidney worm infection, Dioctophyme renale infection History of discovery Dioctophyme renale was discovered in 1583. Almost two centuries later, in 1782, Johann Goeze first described D. renale upon discovering the worms in a dog kidney. The family Dioctophymidae has only one genus (Dioctophyme), and the name of the genus was in contention (with the possibility of being Dioctophyma) for two hundred years. The issue was finally resolved by the International Commission on Zoological Nomenclature in 1989. In 2003, D. renale eggs were discovered in six human coprolites in the neolithic site Arbon-Bleiche 3, Switzerland. This location is near a lake, which likely provided early humans with access to freshwater fish and frogs. The samples were dated from 3384 to 3370 BC, and is evidence that the prevalence of this infection was higher in early human history (before full understanding of proper cooking techniques). Eggs were also found in 2019 in a well-preserved largely fish-eating settlement in England dating to 900 BC.'[]Dioctophymosis Clinical presentation in humans Individuals with Dioctophyme renale infection (known as dioctophymosis) typically present with unspecific symptoms including hematuria (blood in urine), nephritis, loin pain, renal enlargement, and/or renal colic (intermittent pain in the kidney area), which may result from the rare migration of worms through ureters. In some cases the fibrosis occurring after parasite infection is an incidental finding in ultrasound or CT scan, mimicking renal cancer, leading to radical nephrectomy. Adult worms typically only infect one kidney. The kidney is destroyed because of fibrosis, the development of excess fibrous connective tissue. Global renal dysfunction is typically limited because the non-infected kidney is usually capable of assuming the increased work. However, parenchymal inflammation can lead to death in extreme circumstances. Transmission and life cycle Adult Dioctophyme renale inhabit the kidney (typically the right kidney).