Horses in Southern Alberta Diagnosed with Pigeon Fever

More than 10 horses in southern Alberta have been diagnosed with pigeon fever this fall, an illness so-named for the common symptom of swellings in the chest.

Dr. Kelsey Brandon of Claresholm Veterinary Service said the clinic has treated several animals and it has also been diagnosed in horses from the Fort Macleod and Lethbridge areas.

Though not usually fatal, the fever results in abscesses that have to mature before they can be lanced, drained and regularly flushed while healing.

“We give (the horses) pain medications while they have the abscesses and they’re maturing,” said Brandon. Ultrasound tests reveal the proper time for lancing and treatment, which is done under sedation.

Pigeon fever is caused by a bacterium spread by flies. When the flies bite horses, they can transmit the illness.Horse to horse spread is possible but rare because it involves direct transfer of pus or exudate from one horse to an open sore of another.

Early swelling can be confused with results from bruising. Symptoms can appear on one or both sides of the chest, with swelling also common on the belly, neck and head.

“Some horses do get sick from it and some do get internal abscesses. About eight percent of the horses that get external abscesses get internal abscesses and of those eight percent that get internal abscesses, 30 to 40 percent of those are fatal,” Brandon said.

This year was considered a bad fly year for livestock. Brandon said she recalls a few cases in the region several years ago but the illness is far more common in the southern and western United States.

Prairie winters tend to limit survival of the bacteria and current risk has been reduced by cooler weather.”It’s usually a late summer, early fall thing when there’s lots of flies and its dryer out.”

Prevention involves fly control, use of fly spray, masks and sheets on horses, and wearing gloves when handling horses with draining abscesses.

For more information on new disease control guidelines, please read “Drought might have contributed to upswing in pigeon fever in horses in the United States” on the American Quarter Horse Association web site,

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