SummaryDioctophymosis is a parasitic disease occasioned by the so-called "giant kidney worm", Dioctophyme renale, a nematode with an indirect life cycle. This parasite's definitive host is the mink, Mustela vison, though numerous wild and domestic mammals as well 1 as man can serve as final hosts. The worms also can be in ectopic locations in the body.We surveyed 692 canines by ecography, urine sampling, surgery, necropsy, and clinical examination and diagnosed 244 cases of dioctophymosis (35.3%). Of the cases of dioctophymosis identified, 30.7% were obtained by ecography, 45.9% by urinalysis, and 17.6% by both those techniques -in addition to positive findings through surgery (2.5%), necropsy (2.5%), and the spontaneous elimination of the parasites (0.8%). Cases of dioctophymosis were observed in animals as young as 4 months of age up to 15 years.The frequency of D. renale diagnosis throughout the sampling period varied significantly. There was a statistically significant association between risk factors (swimming in the river, eating frogs, fish or eels, drinking ditch water) and the prevalence of infection. It was discussed the period missing after infection in canines.

Dioctophymosis is an helminthiasis with an indirect life cycle caused by Dioctophyma renale. It may affect both humans and other mammals. The purpose of this study was to determine the prevalence of the parasite in male canines of different ages, living in a wild riverside area of La Plata River with favourable characteristics for the development of eggs, intermediate or paratenic hosts and completionof the life cycle of D. renale. 171 animals were surveyed and samples were collected through urethral catheterization. The samples were processed by means of centrifugation at a relative centrifugal force of 700 g and microscopic observation of sediments. 42.1% of canines exhibited patent Dioctophymosis in their kidneys. Male canines between the ages of 2 and 5 showed the highest frequency of positive results. Several epidemiological risk factors are discussed that, when associated, might favour the high prevalence of this parasite in the area. The need for equipment for the indirect diagnosis of the disease in canines and other animals prone to infection is clearly demonstrated.