Sheila McDonald, a veterinarian in Kelowna, British Columbia, estimated 400 to 500 horses in that area had pigeon fever in 2010 but said she didn't hear of any cases last year. An outbreak in 1990 was followed by 20 years free of pigeon fever, she said.
McDonald said the outbreaks tend to be limited, and if flies carry the disease, they don't take it far.
"It seems to get on a farm and spread horse to horse, but not too far in the neighborhood," she said. "You may see it next door but not two blocks away."
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