The death of 16-year-old Courtney "Kay" Richard from viral meningitis was more than a little unusual. Several state epidemiologists and national researchers say they could not recall the last time a previously healthy person died from the disease.

Friends from Chantilly High School say the popular sophomore looked fit before she checked into the hospital June 13. What's more, she was an athlete who played volleyball for the school and in youth clubs.

That is largely why local health officials consider the death of the vigorous teenager so shocking. Viral meningitis usually does not kill unless it joins with another disease or attacks someone with a weak immune system, such as an infant.

Then there's this mystery: Infectious disease specialists working on her case have not been able to identify the virus that caused the condition in Courtney, her 16-year-old classmate and a schoolteacher at Armstrong Elementary in Reston. The classmate and teacher are recovering.

"Nobody could remember any cases like this," said Lucy Caldwell, spokeswoman for the Virginia Department of Health.

The last known fatality attributed to viral meningitis in Virginia was in 1993 in the Tidewater area, according to state records, but the case is so old that no information is available on whether other circumstances may have contributed to the death, said Leslie Branch, a veteran disease surveillance coordinator for the state Health Department.

National statistics on the illness are spotty, partly because the federal Centers for Disease Control and Prevention dropped it in 1999 from a list of illnesses that should be reported to the agency. Virginia did the same that year with its list. Since then, the disease has not drawn much attention, compared with the more deadly bacterial meningitis.

"Without this death, there would not have been so much attention paid to viral meningitis," Gloria Addo-Ayensu, Fairfax County's health director, said this week.

Meningitis is the inflammation of the tissues surrounding the brain and spinal cord. Those tissues are difficult for invading infections -- whether viral or bacterial -- to breach. Once they do, however, they can cause much damage, researchers said.

Viruses, which are less harmful, have many ways they can get into the body, he said. The most common, enteroviruses, can be passed by sharing food or coming into close contact with someone who has the disease. Other viruses can be spread by mosquitoes. Even such well-known viruses as herpes, measles and West Nile can cause meningitis. Doctors say spread of the illness can be limited by frequent hand-washing.

For viral meningitis patients, there's encouraging news and bad: Almost everyone recovers fully with a little rest; some exhibit such mild symptoms that they don't realize they are infected. But there is no cure if it turns serious.

Bacterial meningitis, on the other hand, is an infamous killer. The body has few effective defenses against bacteria, which multiply within a host. Without treatment, the disease often can lead to death.

Vaccinations exist for several types of bacterial meningitis and many colleges require them for incoming freshmen. In addition, the CDC and most states keep careful track of the disease.

Although no precise national statistics exist on viral meningitis, CDC epidemiologist Nino Khetsuriani headed a 12-year study of the disease beginning in 1988. During that time, 434,000 people were hospitalized with the illness, usually to make sure they did not have bacterial meningitis. Of those, 1,700 died. Most of the fatal cases affected infants or those whose immune systems had been compromised from another disease, the study said.

The number of fatalities was too small for follow-up research, she said.

In comparison with the viral meningitis figures, an average of 114,000 people are hospitalized a year for flu, the CDC reported, and 36,000 Americans die annually from complications of flu.

The fact that deaths from viral meningitis are rare, however, is of little comfort to the family and friends of its victims or to the medical specialists involved in the case.

"Anytime a young, healthy person dies, it's always upsetting and alarming," said Julia Murphy, an epidemiologist in Virginia's Department of Health.

Tiffany Aaron, 16, lights a candle in memory of Courtney "Kay" Richard, 16, at Chantilly High School a day after Richard died.