Pigeon fever isn’t related to birds but is named for the abscesses sometimes seen on infected horses’ chests (seen here). | Photo: Sharon Spier

—Gail, Australia

A. No. 1: Pigeon fever is not caused by birds. It’s a Gram-positive bacterial infection of Corynebacterium pseudotuberculosis, so it not a viral or parasitic disease. It does occur worldwide in horses.

Interestingly, in Australia, it’s very prevalent in sheep and goats, but not in horses. There are different strains of the bacteria that are seen in sheep and goats versus horses, and horses can’t catch it from sheep or goats. I would encourage you, if you’ve see suspected cases in horses, to do some cultures and see if it truly is this bacterium causing problems