The sudden death of a Slippery Rock High School teen-ager has been determined by UPMC Children's Hospital, Pittsburgh, to be post-infectious encephalitis, according to her physician.

The active 17-year-old Ashley Lynne Anderson died Feb. 8, stunning the already grieving school district which dealt with the deaths of four high school students after a Jan. 1 car accident. Last fall, a high school girl was struck by a car and killed.

Stacy Frederick of Forestville said it would have been harder if her friend Ashley had been the first to die. But her death was also scary in the beginning, she said.

Stacy's mother, Lorie Frederick, said the deaths from the automobile accidents were awful but "more understandable. With Ashley, they told us, 'She's doing so well. You can't die from it.' Then, a phone call saying she's dead. How can that happen?"

Dr. Ken Dunkle, Ashley's family doctor from Harrisville, informed parents at a meeting last Thursday about Children's Hospital's judgment to ease fears that her unexpected death came from something contagious.

"There were rumors that people were burning things of Ashley's but they weren't true," Stacy said.

With recent cases of meningitis in New Jersey and Pittsburgh, along with Ashley's preliminary diagnosis of viral meningitis, people were panicking because "they hear about meningitis all at the same time," said Slippery Rock school Superintendent Lee Beaton. "People were not hearing any differentiation, just (the word) 'meningitis.' "

Ashley's death was more mysterious than the preliminary diagnosis. Children's Hospital believes her bout with mononucleosis in January stirred up her immune system, Dunkle said. That led to the encephalitis; basically, the swelling of her brain and low blood pressure, he added.

Results of an autopsy of Ashley are not expected for six weeks, Hefner said.

However, fewer than 1 percent of children get post-infectious encephalitis from mononucleosis, he said. "It's so rare, no one really understands it."

And it's hard for people to understand how six active, well-liked and bright high school students could die so young.

"We have ongoing counseling and counseling services ... and we're trying to keep things as normal as possible because that seems to work best," Beaton said.

Ashley's death has also affected Slippery Rock Area Elementary School where she was a cheerleading coach, Beaton said. "And she has a sister in the middle school, so it affects the middle school, too."