Horses coming down with pigeon fever

Symptoms of a contagious animal disease called pigeon fever have been found in dozens of horses in Eastern Oregon this fall.

Despite the name, the disease is not spread by the bird. Rather, the bacterial infection can cause abscesses that lead a horse's chest to swell like a pigeon's.

Dr. Fred Robinson of Riverside Veterinary Clinic in Pendleton said he has seen an increasing number of cases this fall, just as he did in 2005.

"There were 80 or so horses treated then, and at this point, with the season not over, we're approaching 50 horses."

Dr. Jason Down of the Hermiston Veterinary Clinic said he's only seen four potential cases this year, but he noted that Idaho veterinarians are noticing an uptick.

"This is the time of year that you see it, early fall, late fall," he said. "It's endemic in California. It's really common to that area."

Though pigeon fever gets it name from the swelling in the chest, the disease can cause swelling anywhere on the horse's body. The animal feels pain when touched on a swollen area, so owners and caretakers must look for the swelling because horses don't give any other clues.

"They don't usually go off their feed, and the horse's attitude doesn't change," Robinson said.

Down said a veterinarian can confirm the infection only with a bacterial culture. The infection is contagious among horses, so owners should isolate infected animals. Down said it's important to drain the abscess so it doesn't infect other horses — then clean up well.

"People don't get it, but they can carry it among horses on their clothing, boots, tools," he said.

The bacteria live in the soil and enter the animals' skin through routine abrasions. The incubation period can run from a few days to several weeks and it's generally not fatal.