Wasting Disease Associated with Cutaneous and Renal Nematodes, in Commercially Obtained Xenopus laevis

Xenopus laevis, the South African clawed frog or toad, is a member of the family Pipidae. Now in high demand for research purposes, they are available commercially. Its reported lifespan is up to fifteen years. Investigators and caretakers are frustrated when commercially obtained, young frogs (four years or younger), not subjected to any studies, "waste" and die. The wasting syndrome is characterized by anorexia, color change, and "flaky skin." Often the first sign of this syndrome is the presence of large fragments of "flakes" of desquamated epithelium in the water. At necropsy, these frogs are thin and have rough skin instead of smooth slimy skin. Histologic examination reveals tortuous intraepithelial cavities or tunnels that contain nematodes, and associated mild to moderate granulomatous inflammation. Nematodes are also found in the kidneys of some of these frogs, usually in Bowman's space, wrapped around the glomerulus. The cutaneous capillarid nematode is identified as Pseudocapillaroides xenopi. Successful treatment with ivermectin and thiabendizole has been reported. The renal glomerular nematode has not been identified.