Tiny Tapeworms are Not New to Idaho

Recent concerns about a parasitic tapeworm have come up in letters to the editor and at Idaho Fish and Game Commission meetings. The tiny tapeworms - known as Echinococcus granulosus - are not new to Idaho. And health experts say incidents of human disease from this tapeworm are rare. The tapeworm, no more than one-quarter inch long, is endemic in most sheep raising areas of the world. Cysts formed by the tapeworm larva were found in domestic sheep from Idaho that were sent to California for slaughter in the late 1960s and early 1970s. Cysts were found in a mountain goat in 2006 and in mule deer and elk in subsequent years in several areas of central Idaho. Adult tapeworms were found in 39 of 63 - 62 percent - wolves collected from 2006 to 2008 in Idaho. Similar prevalence occurs in Montana. Coyotes and foxes have not been tested for the tapeworm, and the prevalence rate is unknown. All the wolves captured in Canada and relocated in Yellowstone National Park and central Idaho in 1995 and 1996 were sampled for disease in blood and feces and for external parasites. They also were treated twice for lice, roundworms and tapeworms before being released. This tapeworm requires two hosts to complete its life cycle. Tapeworm larvae form cysts in the body cavities of deer, elk, moose, domestic sheep and domestic cattle; dogs, wolves, coyotes and foxes pick up tapeworm larvae when they eat infected ungulates. The tapeworms mature and live in the small intestines of the canines. Adult tapeworms produce eggs that are expelled in feces. Ungulates, in turn, ingest the eggs while grazing. The eggs hatch and develop into larvae, and the cycle continues. Human infections with the tapeworm are rare, but have been found worldwide. In Idaho, at least three reports of human infections are known, with the earliest dating to 1938. Throughout the world, most human cases occur in indigenous people with close contact with infected dogs. Humans can be infected by ingesting eggs from feces, usually from a domestic dog. In humans, cysts usually develop in the liver or lungs. Symptoms depend on cyst location and size. The disease is treatable with drugs or surgery. Where the parasite is found in wolves and wild ungulates, most wildlife management and public health agencies consider the public health significance to be low. Normally the tapeworm is not harmful to carnivores. But heavy infections may be associated with diarrhea or poor body condition. In ungulates, the presence of large numbers of cysts can lead to respiratory difficulty. The presence of cysts in livestock at slaughter is generally not of concern, and if present, is trimmed from the edible product. For additional information see the Fish and Game Web site at: http://fishandgame.idaho.gov/cms/wildlife/manage_issues/echinococcus.cfm. Tips to Avoid Infection

• The potential for human exposure to the tapeworm eggs in wolf feces or fecal contaminated hides is relatively low.
• Human health and wildlife agencies encourage hunters to use latex or rubber gloves when handling dog or wolf feces and when skinning and field dressing wolves, coyotes and foxes.
• Idaho Fish and Game encourages all hunters to wear latex or rubber gloves when field dressing and skinning any wildlife carcass.
• All wild game meat should always be cooked thoroughly. Do not feed uncooked meat or organs of deer, elk, moose or sheep to dogs.
• Regular deworming of domestic dogs and good hygienic practices, such as wearing rubber or latex gloves when handling feces and washing hands after handling feces, by anyone in contact with dogs and dog feces are the best methods of control and prevention of the tapeworm in humans.