"I have nightmares every night about it,'' says her mother, Evelyn.
Her doctors diagnosed Creutzfeldt-Jakob disease, or CJD, a fatal disorder closely related to the human form of mad cow disease.
"It's horrible, just unbelievable," says her mother. "I said goodbye, but I don't think she heard me."
Doctors were certain her disease did not come from beef, but occurred randomly, so-called sporadic CJD. But, as CBS News Correspondent Wyatt Andrews reports, Carrie Mahan's good friend Janet Skarbek read about another local woman, Carol Olive, who was also diagnosed with CJD.
"And then it says Creutzfeldt-Jakob disease," says Skarbek. "I thought, 'Oh my gosh, I'm going to read farther,' and then it says she worked at the Garden State Racetrack."
And that's when the light bulb went on.
Both Olive and Carrie Mahan worked at the now closed racetrack and ate lunch there every day. When Skarbek found a third CJD victim, broadcaster John Weber, who had a season pass to the track, she dug more and eventually found seven CJD victims in the area. All had some connection to the track. That, she thought, can't be random, so she asked the Centers for Disease Control to investigate.
But, Skarbek says, they weren't interested in it because it was only sporadic CJD.
Skarbek suspected she'd found a disease cluster, but the CDC said no. Even seven deaths was within the norm of one in a million. It was sporadic CJD -- and thus there was no in depth investigation.
By contrast, British authorities track down every report of sporadic CJD: the very system of strict surveillance that led to the discovery of variant CJD, the type that is caused by mad cow.
"We don't know the cause of sporadic CJD so any change in the pattern of the condition would be cause for investigation to see if it may give us clues to the cause," says professor Peter Smith, a CJD investigator.
In the U.S., Dr Pierluigi Gambetti, the top CJD detective, is trying to learn if variant CJD reaches America. He does not think the New Jersey outbreak was mad cow disease, but he only saw tissue from two of the seven possible victims. Why? Only 26 states have to report CJD he says, and there are very few autopsies.
He worries that human mad cow could surface in the U.S. undetected.
"God forbid one of them could be a case of variant CJD - the form that we acquire by eating contaminated beef and we would never know," says Gambetti.
When told that not one case has been found to have a link to mad cow disease, Skarbek says, "Oh, it's easy to say there's not a link when you're not looking."
What Skarbek has truly discovered are the gaps in knowledge about CJD. A disease not always discovered -- and not always investigated -- by a government certain mad cow in humans isn't here.