Purdue News

April 3, 1992 Slowly Spreading Parasite Demands Caution WEST LAFAYETTE, IND. – A parasitic tapeworm found most often in foxes and coyotes may pose a health threat to people, especially those who trap or handle the animals, says a Purdue University authority. Echinococcus multilocularis (pronounced ee-KINE-o-cock-us mul-tie-LOCK-you-lair-iss) is the scientific name for the microscopic parasite that now has been found in Indiana. The first case was a coyote in Tippecanoe County in January 1991, says Dr. Kevin R. Kazacos (pronounced kuh-ZAK-us), a parasitologist in Purdue's School of Veterinary Medicine. So far, the parasite has been found in foxes and coyotes in mainly the northern half of Indiana but also as far south as Parke County. It appears to have spread into Indiana from the Dakotas and Minnesota, says Kazacos. "We are learning more about echinococcus in our area," says Kazacos, one of only three or four researchers in the country studying the parasite. "The parasite now has infected about 20 percent of our state's wild canid population in the north." Canids include foxes, coyotes, wolves and dogs. "It needs to be studied more," Kazacos says. "It's a potential veterinary and human health problem that we need to learn more about." In people, the parasite attacks the liver and can be fatal. The parasite's cycle also involves wild rodents, which become infected with the parasite's larvae by eating eggs excreted in an infected canid's feces. Uninfected canids then can become infected by eating those rodents. People can also become infected by accidentally ingesting the tiny eggs shed in the feces of infected animals. That's why wildlife biologists, hunters, trappers and others who come in direct contact with coyotes and foxes need to be especially careful, Kazacos says. "It's important to handle these animals with caution, avoiding their fecal material, and to wash thoroughly with hot water and soap afterward," Kazacos says. Once inside the human body, the parasite's eggs hatch in the intestine and the larvae travel to the liver. There, the larval parasite grows slowly but extensively, so that it can take years for physical symptoms such as jaundice to develop. Victims may be mistakenly diagnosed with liver cancer. "Treatment of the infection is difficult and relies mainly on surgery," Kazacos says. "You can stop it by surgically removing the affected parts of the liver. If it's deep or extensive in the liver, however, perhaps nothing can be done. Treated or untreated, the disease has a high fatality rate." Domestic dogs and cats that eat infected rodents also can become infected and bring the parasite into close contact with people. "The parasite doesn't develop as well in cats as in dogs, but cats are better mousers," Kazacos says. "In dogs, you could also come in contact with the eggs if your dog tends to roll in wild-animal feces. Then the eggs would be in the fur." It's too early to recommend that dog and cat owners, especially those in rural areas, have their pets immediately checked for the tapeworm by a veterinarian, says Kazacos. Besides, diagnosing echinococcus is very difficult, he adds. However, it's a good idea for rural pet owners to try to keep their pets from eating rodents. "If you do have a cat or dog that eats rodents, it might be a good idea to have your pet dewormed regularly with a drug that will kill any echinococcus, too," he says. The parasite slowly has been spreading during the last 30 years from lower Canada through the upper Midwest and is now found in 11 states. Kazacos says it likely will spread next to southern and southeastern states. "The most alarming thing at the moment is the translocation of wildlife, especially foxes, for hunting," he says. "A lot of foxes infected with the parasite are being exported from the upper Midwest to states such as Texas, Georgia and the Carolinas. Both federal and state authorities are very concerned about this." Kazacos and his graduate student, Scott Storandt, are the only two in Indiana researching the parasite. They're working in cooperation with the Indiana Department of Natural Resources to track the disease. "The first step is to find out where and how extensive the parasite is in wild canids," Kazacos says. "Then we'll look at the wild rodent population. In about another year, we'll look at how prevalent it is in domestic dogs and cats." They also are examining effective treatments for the parasite that could be used in pets. Purdue News Service: (765) 494-2096; purduenews@purdue.edu