The Torris Plague was an epidemic on Alzarius.
At one point in Alzarius' history, some of the smaller continents were involved in skirmishes with each other. The Torris Plague was designed by one faction to affect small animals, like dogs and other pets. It eventually mutated and began killing Alzarians.
As a result of the plague, any remaining dog or other pet was hunted down and destroyed to prevent it from spreading the infection. (PROSE: A Boy's Tale)