Teen cheerleader's sudden death was caused by strep: 'We wouldn't wish this nightmare on anyone'

A 13-year-old Kentucky girl who died hours after falling ill at her cheer competition was suffering from strep, her family has learned, two months after the sudden loss.

"Apparently, an underlying Strep infection overwhelmed her immune system with little or no warning, and catastrophic results," the family of eighth-grader Lilliana Schalck said in a statement. "We wouldn't wish this nightmare on anyone."

But Lilliana's family said in the statement that speaking publicly about her autopsy report "might help prevent a similar outcome for someone else."

"Lilliana would surely help if she could, and this is just an extension of that spirit."

Lilliana was warming up at her All-Star competition on Feb. 23 when her hands went numb and feet started tingling, her father, Dan Schalck, told ABC News in February.

"I kind of took her aside, was maybe going to get her some fluids," Schalck said. "She was just getting kind of weaker, just not acting herself."

Lilliana was rushed to the emergency room at Nationwide Children's Hospital.

"In the ICU they were working on her," her father said, referring to the intensive care unit. "At some point I was able to get close, hold her hand. At that point they just couldn't do anymore."

Within hours of falling ill, the 13-year-old was dead.

Lilliana turned out to have had a widespread infection due to group A Streptococcus (GAS), the same bacteria that causes strep throat, according to the autopsy report obtained by ABC News on Friday. The coroner cultured the bacteria from her blood, spinal fluid, meninges and lungs.

Although GAS more commonly causes minor infections like strep throat and impetigo (a superficial skin infection), it can also cause serious and life-threatening infections like cellulitis (a deeper skin infection), necrotizing fasciitis (so-called "flesh-eating" disease), pneumonia and toxic shock syndrome.

About 11,000 to 13,000 cases of invasive GAS disease occur each year in the United States, compared to the millions of non-invasive GAS infections, according to the CDC (Centers for Disease Control and Prevention). Anywhere from 1,100 to 1,600 people who develop an invasive GAS disease will die each year.

Meanwhile, Lilliana's family said that they remain "in shock as we navigate through the most difficult time imaginable -- we find new 'Firsts' and 'Lasts' every day."

The family also expressed "appreciation for the outpouring of love and support from her friends, teachers, coaches, and administrators at Highlands Middle and High Schools, her extended family at Premier Athletics, plus the entire cheer community across this whole country, and most of all the good people of Fort Thomas."

"We are so thankful, and honestly overwhelmed, by those that have reached out and continue to find new ways to support Lilliana's memory on an almost daily basis," the family said.