Horses develop wounds in many ways. One is by infection with a water-loving microbe.

Pythium [PITH-ee-uhm] insidiosum [in-sid-ee-OH-sum] is an aquatic mold that thrives in warm climates, like the Gulf coast. But now, in the face of global warming, it’s spreading farther afield. Horses can develop pythium infections from exposure to swamps, standing water — any water body that doesn’t freeze over.

Wounds from pythiosis often affect a horse’s lower limbs, but they can crop up anywhere. These wounds grow dramatically over hours, turning into painful, draining lesions that don’t respond to common medications. Without timely surgical intervention, pythiosis can be deadly.

If you see suspicious signs, there’s no time to waste.