Some city dwellers don't want any animals in their homes or backyards. Others want only household pets. Still others enhance their landscapes to attract wildlife.

As more wild animals make their homes in cities, whether under a porch, in a wooded park or in a wildlife-friendly backyard, they bring with them the potential for diseases that can affect pets, people and other animals. This has created a need for veterinarians to know more about how these animals impact public health.

"In rural areas, people who work with agricultural and wild animals have learned that you can get diseases from animals. People in urban areas are less likely to have that awareness," said Laura Hungerford, epidemiologist at the University of Nebraska's Great Plains Veterinary Educa-tional Center at Clay Center.

The Institute of Agriculture and Natural Resources veterinary scientist teamed with colleagues from research foundations and laboratories across the country to study raccoons living in residential areas, wooded preserves and parks in Illinois. Scientists captured the masked critters, collected samples and fitted them with radio tracking collars to determine where they lived, the diseases they carried and the impact of these diseases on pets and their human owners. They used geographic information systems and statistical analyses to detect disease patterns.

"The whole idea of disease in wildlife in urban areas has not been looked at that closely," Hungerford said.

The researchers found that 50 percent of the raccoons tested positive for leptospirosis, a bacterial disease that can affect humans as well as animals, she said. Dogs can become carriers of these bacteria through contact with urine from infected animals. The disease can be severe or even fatal for livestock and pets. Humans also can get sick by working with infected animals or swimming in or drinking contaminated water.

A high percentage of the raccoons also tested positive for canine distemper, a disease that does not affect humans but can be fatal for unvaccinated dogs, Hungerford said.

Raccoons can carry rabies, and many baby raccoons carry roundworms and other non-life threatening diseases, she said.

"If the study were replicated in Nebraska, we'd expect similar results," she said.

Because humans have eliminated many of the raccoons' natural predators such as coyotes and wolves, raccoon populations have increased. Although it is not a natural setting for them, raccoons are very adaptable to life in the city and the suburbs, particularly when favorable habitats are created for them.

"In fact, raccoons reach their highest densities in places they can find extra food from humans or garbage," Hungerford said.

"All wildlife can carry similar diseases. Raccoons are of special concern in towns because we're more likely to have closer contact with this amusing and intriguing species."

Grants from Cook County, Ill., and the Max McGraw Wildlife Foundation helped fund this research.

– Linda Ulrich

IANR Veterinary Scientist Laura Hungerford demonstrates some of the gear used to track raccoons living in cities. The antenna and a computerized map help track raccoons equipped with radio collars. A research team tracked raccoons to learn more about the diseases carried by raccoons and other wildlife living in cities.