A carriage horse named Ryder collapsed Wednesday in New York City’s Hell’s Kitchen neighborhood. While initial reports suggested the medical emergency was due to heat exhaustion, a carriage driver who works at Ryder’s stable told the New York Post that the horse was examined by a veterinarian and diagnosed with a neurological disease caused by possum droppings: Equine Protozoal Myeloencephalitis. However, it is unclear whether that was the sole contributor to the horse’s scary collapse. In videos of the incident, members of the crowd can be heard chastising the horse’s driver for “letting it happen.” Animal activists are demanding an end to horse drawn carriages in the city. “Whether he collapsed from overwork and heat exhaustion, or, even worse, overwork, heat exhaustion and untreated EPM, there is no excuse to treat a horse like an expendable machine,” Dr. Jim Keen, director of Veterinary Sciences for Animal Wellness Action and the Center for a Humane Economy, told the Post.