Occurrence of Dioctophyma renale in Louisiana, with Remarks on the Size of Infertile Eggs of This Species

Abstract

During a survey of parasites of south Louisiana fur-bearing mammals, carried out under a grant from the Louisiana Fisheries and Wildlife Commission, it was decided to include a study of the giant kidney worm (Dioctophyma renale) in the mink (Mustela vison). A cash reward was offered to the first trapper reporting and delivering a specimen of this helminth in the mink. Gross appearance of the worm and features of its pathogenesis were circulated through the Fur and Refuge Division of the Commission, and provisions were made for preservation of material in the field, as travel in the marshland during the trapping season is difficult. Ehrenford and Snodgrass (1955) reported a total of 121 cases of D. renale in North America, together with 5 new cases from dogs in Indiana. These authors, together with Meyer and Whitter (1950), found that this parasite occurred in the District of Columbia, Arkansas, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Michigan, Minnesota, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Virginia and Wisconsin and in Manitoba, Ontario and Quebec provinces of Canada. In the present study 4 female and 1 male D. renale were recovered from 3 mink. One solitary female worm was found in a hollowed-out kidney containing a bony spicule like that described by Hallberg (1953). Due to its disintegrating, friable state this specimen was not measured. The mink from which the worm was recovered was trapped February 14, 1955 in the Vermillion Bay region. Three other female specimens were obtained from the peritoneal cavity of a second mink captured January 8, 1955 on Marsh Island Refuge, Louisiana. These measured 32.2, 31.0, and 23.5 cm in length respectively by 4.0 to 5.0 mm in diameter. Examination of the parasitized carcass showed no evidence of recent or earlier penetration into either kidney. The last specimen obtained was a single male worm in the peritoneal cavity of a mink captured March 2 on Marsh Island. This specimen measured 17.5 cm in length by 2.5 to 3.0 mm in diameter and, again, no damage to the host was evident. In addition to the above specimens, one of us (E. C. F.) has in the Museum of Parasitic and Tropical Diseases of Tulane Medical School a single large female worm from the peritoneal cavity of a dog which he autopsied in New Orleans April 23, 1931. Length and width measurements were done on 35 eggs from one of the female worms from the mink taken on Marsh Island Refuge, and the same number from preserved material from the dog. Eggs of the mink parasite ranged from 60 to 81 microns by 39 to 46 microns, with a mean of 68.7 by 42.4 microns, and those from the dog similarly ranged from 60 to 72 by 38 to 45 microns with a mean of 67.2 by 41.3 microns. Due to the absence of accompanying male worms in the mink and dog, we concluded that these were infertile eggs. Morgan and Hawkins (1949) gave the size range for D. renale eggs as 71 to 84 microns by 46 to 52 mi-