"The genetics of strep have changed," he said. "We don't see these outbreaks as frequently as we used to. But every once in a while one runs into a strain of a particular strep group A that has the capacity to cause serious invasive disease."
According to the Centers for Disease Control and Prevention, about 9,000 to 11,500 cases of the invasive strep infection occur each year, resulting in about somewhere between 1,000 to 1,800 deaths annually. In contrast, several million cases of the less serious strain known as strep throat are reported each year.
Schaffner says that the amputations Katy underwent are not uncommon for individuals suffering from the invasive infection.
"One of the ways to try to stop it is to try to get ahead of it and cut off the piece of the body where the infection is so it doesn't keep advancing," said Schaffner.
Schaffner also said that there is no way to know whether Katy's home birth made her more susceptible to the disease.
"It's like asking why did that person get hit by the truck, it's just that this is the strain of strep [Katy] happened to run into," he said.
Enough of Katy's arms and legs exist that prosthetics will be an option in the future, said Hayes. But for now, Hayes is focusing on stabilizing his wife. Katy has moved to Parkland Hospital in Dallas, which has a burn-trauma unit that can treat her flesh wounds. She is also going through intensive physical therapy.
Hayes says that he hopes to take Katy home soon to their newborn, their 6-year-old son and her 16-year-old daughter. He knows it will still be a long road to recovery.
Asked why he decided to share his wife's story so publicly, Hayes said that he did to show others that patients sometimes need help advocating for themselves.
"I want people to know they have rights, and if you have a loved one in a hospital you can't afford to sit and just gieve and do nothing," he said. "You have to be active participants and educate yourself."
"My wife is an incredible woman," he said, "She's worked on the set of the 'Teenage Mutant Ninja Turtle' movies, has hiked the Alps and has been a massage therapist for 17 years."
"You took a woman with that much life and saw her wake up as a quadruple amputee," he said. "But it will be worth it. She's alive and we won't let her forever be just a torso."
"It's hard for me to accept praise what I've done for Katy," said Hayes. "I don't feel like there is any option, I'm just doing what anyone would do for someone they love."