AMHERST — A student at the University of Massachusetts has been diagnosed with a meningococcal illness, according to a University Health Services statement sent out Tuesday evening. The student is being treated at an area hospital, and the illness is described as “serious.”

The bacteria that caused the illness, Neisseria meningitidis, are contagious and transmitted through “close personal contact,” according to the statement, which names “coughing, sharing drinks and kissing” as possible routes of transmission.

“None of the bacteria are as contagious as the common cold or the flu, and they are not spread by casual contact or by simply breathing the air where a person with this illness has been,” the statement says.

Neisseria meningitidis can cause meningitis, an infection of brain and spinal cord tissue, or sepsis, an infection of the blood. These can be fatal if untreated, but there are “safe and effective antibiotics that can reduce the possibility of infection,” according to the statement.

According to UMass public health nurse Ann Becker, the student, who is suffering specifically from meningococcemia, a type of sepsis, is “improving” at a local hospital.

Becker, who helps track communicable diseases and possible outbreaks and runs vaccination campaigns, said meningococcal diseases are “rare and relatively random,” occurring sporadically on campus every several years.

The bacteria, Becker said, can exist in the nasopharynx of anywhere from 20 to 40 percent of the population, but usually don’t cause any illness; a weakened immune system will “trigger” the vaccine-preventable illness in some people, she said.

Symptoms of a meningococcal disease are different depending on the person, Becker said, but the most common symptoms are fever, nausea, vomiting, neck aches and body aches, and flu-like symptoms without respiratory problems. The rapid onset of such diseases can cause a severe illness within a few hours.

The student who contracted the illness originally went to University Health Services feeling ill. On Tuesday, shortly before the university statement was sent out, the student’s illness was identified as meningococcemia.

The university, local and state health officials are meeting and telephoning anyone who could have been in close contact with the infected student and have the “most significant risk of infection.”

“That’s been underway right from the beginning,” Becker said. “The reason we take such strong measures around it is because it is potentially fatal.”

The University Health Services statement advises the UMass community to be “health smart,” suggesting washing hands with soap and water or hand sanitizer, avoiding sharing drinks and personal items that contain saliva, covering coughs and sneezes with a sleeve and refraining from touching one’s eyes, nose or mouth, from which germs are easily spread.

The university highly recommends that students receive immunizations for meningococcal disease, and Massachusetts state law mandates that all incoming students who plan to live on campus receive at least one vaccine dose, with a second recommended.

As of Thursday afternoon, there were no known cases of the disease having spread via the infected student.