At Princeton University, where eight cases of bacterial meningitis have surfaced this year , officials have put up posters and e-mailed students warning them to guard against spreading the potentially fatal disease. Federal officials have taken the rare step of allowing the university to vaccinate thousands of students beginning next week using a drug not yet approved in the United States.

At the University of California at Santa Barbara, where a fourth bacterial meningitis case was confirmed this week, a freshman lacrosse player had both feet amputated. Campus leaders have suspended fraternity parties and other social events and ramped up cleaning in residence halls and recreation facilities.

The threat of meningitis has long been a concern on college campuses, where the cramped living quarters, crowded classrooms and teeming party scene create an environment where it can spread more easily. The disease has largely vanished from colleges and universities in recent years, as dozens of states required students to be vaccinated against it before arriving on campus.

But officials who monitor the disease are troubled by the recent outbreaks in California and New Jersey, in part because of the number of cases but also because each involves the uncommon “serogroup B” type of bacterial meningitis, for which the country has no approved vaccine.