Risk of developing meningitis is low
DEAR DOCTOR: One of the schools in my area has been the focus of news reports about a bacterial meningitis case. How contagious is this disease?
DEAR READER: Bacterial meningitis cases in school-age children, adolescents and college students are predominately caused by two organisms. Streptococcus pneumoniae causes nearly 50 percent of meningitis between the ages of 2 and 18, while people in their teens and college years face an increased risk of meningitis caused by Neisseria meningitidis.
The Streptococcus pneumoniae bacterium is spread by close contact with people who cough or sneeze. Upon inhalation, the bacteria adhere to the back of the nasal passage in an area called the nasopharynx, where they sit without causing any problems.
In most people with this colonization, the immune system keeps the bacteria from invading the cells of the body. However, when the immune system is weakened or when the body is fighting a viral infection, such as influenza, the bacteria can then invade the cells. From there, the bacteria can enter the bloodstream and cross
through the blood-brain barrier, replicating readily in the cerebrospinal fluid, leading to the symptoms of meningitis.
The Neisseria meningitidis bacterium is passed from one person to another by secretions from coughing or by saliva from kissing. It’s also passed easily among people in close contact. Like Streptococcus, Neisseria also settles in the nasopharynx, where the immune system similarly keeps the bacteria from invading into the cells of the body.
The bacteria that cause meningitis are quite contagious, but a person’s general risk of developing the illness is very low. In addition, children and adolescents are vaccinated for three types of bacteria that can lead to meningitis.
If your child has been exposed, watch for fever, neck stiffness and lethargy. If he or she begins to exhibit these symptoms, take him or her to a doctor as soon as possible.
Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.
Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA 90095.