Human infection spreading to some pets, veterinarians say

A week ago, Larry Davidson was freaked out when his dog's veterinarian -- decked out in a green gown, rubber gloves and a face mask -- announced that the dog at Mr. Davidson's feet had a highly contagious infection.

"It just knocked my socks off," said Mr. Davidson, who works in printing on Signal Mountain.

Mr. Davidson's 7-year-old German shepherd-malamute mix, Luna Lee, had contracted a drug-resistant staph infection called methicillin-resistant Staphylococcus aureus, or MRSA.

The infection, potentially fatal among vulnerable human and animal patients, is considered an "important emerging" disease in animals, according to the American Animal Hospital Association.

A skin infection occurred in an area where Luna had gotten a biopsy to check for lymphona. When the area swelled and Luna's health deteriorated, vets at River Emergency Veterinary Clinic on Amnicola Highway did a culture on the wound and diagnosed MRSA last week.

Although Mr. Davidson said no one in his family has been ill, most cases of MRSA in animals are contracted from pet owners, said Dr. Sallye Gregg, director of River. In the past couple of years, she's begun to see pathogens such as MRSA spreading between humans and their pets more often, Dr. Gregg said.

"In the veterinary world it's very unusual, but it's becoming more commonplace," she said.

River has seen 12 to 15 MRSA cases this year, Dr. Gregg said.

Human cases tracked

Human cases of invasive MRSA -- serious cases of the infection that make up only about 7 percent to 10 percent of all MRSA infections -- are tracked by the state Department of Health. The number of cases statewide has hovered close to 1,800 each year from 2005 to 2007, health officials have said. Infectious disease experts attribute the rise in antibiotic- resistant staph infections to inappropriate antibiotic use.

The vast majority of MRSA cases occur in hospitals, where patients with weakened immune systems are susceptible to infections and health care professionals can pass bacteria between patients, health experts say.

But in recent years, public health officials have noticed a growing number of human MRSA cases outside hospitals, in community settings such as schools or locker rooms, leading to concern that the disease is growing more virulent.

The spread may be the reason that pets now are more likely to be exposed to the disease, said Dr. Michael Moyer, vice president for the American Animal Hospital Association.

"I think awareness will drive more veterinarians to (take cultures on more wounds), and I would not be surprised to learn that there's more than we think there is," he said.

Prevention important

To prevent spreading the disease, pet owners also must be sure to wash their hands often, especially if they've been in a health care facility. People can be colonized with a MRSA infection even if they don't show symptoms.

After a week of antibiotic treatments and quarantine, Luna was discharged from the River clinic Thursday, said Mr. Davidson, who must give her antibiotics for another week.

"She's beaming. She looks bright-eyed and bushy-tailed," he said.