Fluffy and Fido are getting a bum rap.

Cats and dogs are often accused of spreading a variety of diseases to humans. But don't be too quick to blame them.

"Disease transmission by pets is blown out of proportion," said Craig Greene, a UGA professor of small animal medicine. "The risk from animals is relatively low; people contract infectious diseases easier from other people than from animals. A person usually gets the disease from the same place pets do."

Cats especially have gained a bad reputation for spreading diseases. Take, for example, toxoplasmosis, which can be fatal to unborn babies if contracted by their pregnant mothers. Although cats can spread the disease, most people get it from handling raw meat, Greene said.

Fluffy and Fido are actually lending a paw in the battle to halt the spread of such diseases. Because most pet-transmitted illnesses cause similar reactions in both animals and humans, scientists study how diseases affect animals to understand how they also affect humans.

Greene uses techniques from molecular biology as well as antigens, which produce antibodies, and immunoglobulin concentrations (blood serum proteins that act like antibodies) to develop diagnostic tests for these diseases. After developing a test, he produces the infection in dogs and cats to test its reliability. Next, he applies the test to naturally diseased animals and studies the results. A reliable test is then used to determine geographic distribution of the disease and individual animal infection.

Worldwide, Greene's tests have helped save lives through early diagnosis of diseases that previously were hard to differentiate. "These diseases may be treatable, but they have to be recognized first," he said.

Greene also has helped take the bite out of tick-borne diseases, like Rocky Mountain spotted fever and Lyme disease, by developing diagnostic tests for both.

Most deaths from Rocky Mountain spotted fever occur because of delayed recognition, and consequently, delayed initiation of antimicrobial therapy. "Rocky Mountain spotted fever is very confusing to diagnose, and can be fatal if not diagnosed and treated in time," he said. With Greene's diagnostic test for the disease, veterinary recognition of the illness has increased, which in turn has decreased the number of human and animal fatalities.

He also has helped put the minds of dog owners at ease by showing that direct transmission of Lyme disease from dogs to people is unlikely.

Also helping veterinary and human clinicians with diagnosis is the textbook Infectious Diseases of the Dog and Cat. Edited by Greene and published in 1990, it has become the primary reference worldwide for these diseases.

Although his tests may help save lives, Greene said common sense remains the best weapon in the fight against these diseases. "People have to be cautious when removing ticks or handling feces," he said. After all, an ounce of prevention is still worth a pound of cure.