Macracanthorhynchus ingens infection in a dog

A 4-month-old sexually intact female Siberian Husky was examined because of diarrhea and 4 flesh-colored annulated helminths that were recovered from the dog's feces. Infection with Macracanthorhynchus ingens was diagnosed on the basis of morphologic features of the adult parasites and ova. Spindle-shaped eggs (mean length, 91 microm; mean width; 54 microm) were obtained from the body cavity of a gravid female specimen. The dog was treated empirically with epsiprantel (5.5 mg/kg [2.5 mg/lb] of body weight) and ivermectin (250 to 500 microg/kg [114 to 227 microg/lb]), and the diarrhea resolved. Infection with this parasite has been reported in raccoons from the same geographic area. Macracanthorhynchus ingens is typically a parasite of raccoons, wolves, badgers, foxes, skunks, mink, and moles; transmission from wildlife to dogs may occur via ingestion of infected intermediate hosts (millipedes).