STANLEY WOODS’ CRITTERS: Vancouver Courier
Wednesday, December 3, 1997

North American Raccoon
Procyon lotor cancrivorus

Intestinal parasite Baylisascaris attacks nervous tissue.
PHOTO: Vancouver Courier, December 3, 1997

p. 11.

Cute 'coons carry deadly disease

Gudrun Will

AVOID THAT CUTE RACCOON waddling through your back yard, warn biological scientists at Simon Fraser University's disease research group. The animal may carry an intestinal parasite that's transferable to humans.

Researcher Bruce Leighton said five of nine road-kill raccoons were found to be carrying the roundworm Baylisascaris. Its microscopic eggs are passed on through the ingestion of raccoon feces. In the last two decades there have been four fatal cases in U.S. children.

"We're interested in urban animals and what they're carrying, given the increasing incidence of raccoons in the Lower Mainland," said Leighton. "There's a disease potential in human-animal interactions."

When the parasite encounters a susceptible host (raccoons usually experience negative effects only when young or in bad condition), it migrates to nervous tissue such as the brain or eye, causing inflamation and tissue damage. Dogs and cats don't pick up the disease, said Leighton, but many other animals like chickens can.

"Kids are more susceptible through playing in the dirt," said Leighton. "Theoretically it can happen here, There have probably been cases that have gone undiagnosed."

Parks board wildlife co-ordinator Mike Mackintosh has been providing carcasses for a similar provincial veterinary project on disease potential of urban raccoons, coyotes, skunks and squirrels. Baylisascaris is the only disease of concern to humans here, he said. While difficult to catch, if it gets into the human system he said it can be extremely serious.

Numbers of raccoons vary naturally, he said, and parasites like the roundworm, or viral infections like distemper, kill off excess populations. Low food supplies and cold conditions allow the parasite to affect raccoons.

"We find large numbers of young raccoons [dead] at this time of year. Post-mortem exams reveal a large amount of Baylisascaris in their gut," said Mackintosh.

Mackintosh and Leighton agreed Vancouver has virtually no risk of other wildlife-borne diseases like rabies. Unlike Ontario, which has rabies-carrying raccoons, here the disease is found mainly in bats, said Leighton.

Squirrels in parts of the U.S. carry bubonic plague, notably in campsites around San Francisco. There's a concern the disease could transfer to urban rats.

Raccoons are actually clean animals that tend to defecate in one place, he pointed out. He and Mackintosh recommend minimizing contact with raccoons and other wild animals. Children or gardeners should wash their hands after playing or working outside.

People should not feed them and it's illegal to keep them as pets.

"You don't want to encourage them into your back yard," said Leighton.