Dawn Manteufel said her husband was perfectly healthy just a month ago and especially loved riding his Harley-Davidson motorcycle.
But then he became ill. And what they initially thought was the flu landed him in the emergency room.
"It hit him with a vengeance," Dawn said. "Bruising all over him. Looked like someone beat him up with a baseball bat."
She said life as they knew it changed forever.
Blood tests revealed an infection caused by the bacteria -- capnocytophaga.
"It took a week, and they were taking his legs," Dawn said.
The infection very likely entered Greg's system by something so common: getting licked by a dog, probably his own.
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"This type of bacteria comes from the saliva of dogs," said Dr. Silvia Munoz-Price of Froedtert Hospital and the Medical College of Wisconsin. "This infection in his blood triggered a very severe response in his body."
That response caused Greg's blood pressure to drop and the circulation in his limbs to decrease rapidly.
"Sometimes it decreases so much that the arms and legs just die," Munoz-Price said.
Dawn is still trying to process all that has happened.
"We can't wrap our heads around it that all of the sudden, he's 48 years old and been around dogs all of his life and this happens," she said.
Still, the couple is looking at what wasn't taken away.
"He kept just saying, 'Take what you need, but keep me alive.' And they did," Dawn said. "Surprisingly enough, they did do it."
Doctors said Greg's case is simply a fluke.
"More than 99 percent of the people that have dogs will never have this issue," Munoz-Price said. "It's just chance."
CNN contributed to this report.