“People can have it in the back of their throats, but it doesn’t cause meningitis until it invades the bloodstream,” DeMaria said. “It is chance whether or not that happens.”

In his e-mail last night, Pertile stressed that “there is no cause for unnecessary alarm.”

“We will take it in stride,” Pertile said in a phone conversation earlier in the evening.

“I think the dorm setting makes the likelihood of this happening less rare,” Pertile said. “This is a very rare occasion, but the likelihood of developing it seems to increase in dormitory and conditions in which people live in close proximity.”

For this reason, many colleges suggest that students get vaccines before moving into dormitories.

There will be a meeting in Eliot House Dining Hall today at 4:30 p.m. for students to talk about the situation.

A Harvard student was diagnosed with the less severe form of viral meningitis in April 1998.

—Staff writer Katharine A. Kaplan can be reached at kkaplan@fas.harvard.edu.

—Staff writer Rebecca D. O’Brien can be reached at robrien@fas.harvard.edu.