RALEIGH, N.C. — Health officials said no new cases of bacterial meningitis have been reported in the Triangle since Thursday.

That is when a University of North Carolina at Chapel Hill freshman was diagnosed with the disease. Jonathan Davis, 18, is in fair condition at UNC Hospitals.

Culture results received by the Orange County Health Department on Monday confirm Neisseria meningitidis, serogroup B, as the bacterium responsible for Davis' illness.

Neisseria meningitidis is the second most common cause of bacterial meningitis in the United States. A vaccine for meningococcal disease protects against four serogroups, but not serogroup B. Davis received the vaccine last spring.

Health officials said students at UNC and North Carolina State University may have been exposed at two parties last week.

As many as 1,500 students have already taken a preventative antibiotic.

"Those who believe they may have been exposed, due to close and direct contact with Mr. Davis within the past two weeks, should seek treatment and monitor themselves for signs and symptoms of meningitis regardless of prior vaccination," said Orange County Health Director Dr. Rosemary Summers.

Symptoms may include: fever, nausea and vomiting, severe headache, sensitivity to light, purple-red body rash, a stiff neck, sleepiness or confusion.

Close contact means people who shared a household with the student or had direct contact with oral secretions. Examples of close contact include kissing, sharing a drink, sharing food from the same plate, sharing a cigarette, or being coughed or sneezed upon.

On average, Orange County experiences one bacterial meningitis case per year, according to the health department.