Reid began wondering whether there might be an exotic virus at work, such as the one responsible for African horse sickness (AHS), a disease carried by biting midges in sub-Saharan Africa. AHS virus affects mules, donkeys, and zebras as well as horses, but it hasn’t been reported in Australia, and it isn’t directly contagious from horse to horse. Furthermore, Queensland’s pestiferous midges don’t generally come biting in September, when the weather is cool.
