The Mystery of Meningitis

Most everyone is familiar with the term ‘meningitis.’ We know it refers to an infection in the fluid and linings surrounding the brain and we know it can be deadly. We also know meningitis is potentially contagious. Beyond that, our understanding of meningitis is cloudy. And we generally tend to fear things we don’t understand, especially those things that are contagious and deadly, right? So let’s explore the mystery that is meningitis with the expectation we can turn fear into understanding.

Meningitis does indeed describe an infection of the fluid surrounding the brain and the spinal cord. Many types of bacteria, viruses, and fungi can be responsible for the infection. They all seem to cause a fever with severe headache and stiff neck. Fungal infections are rare and occur most commonly in people with impaired immune systems. Viral infections, while uncomfortable, tend to resolve on their own and without specific treatment. Bacterial causes of meningitis, on the other hand, are a big worry as they can cause major disability and death.

There are three main causes of bacterial meningitis and each will be explained below.

Pneumococcal meningitis is caused by the bacterium Streptococcus pneumoniae, also called ‘The Pneumococcus’. It is the most common cause of meningitis in newborns and in infants. Cases of meningitis due to pneumococcus, at one time quite common, have been drastically reduced through the use of a vaccine called Prevnar given to infants at 2, 4 and 6 months of age. Meningitis caused by S. pneumoniae is rarely contagious.

Hemophilus meningitis is caused by the bacterium Haemophilus infuenzae type b, also known as ‘Hib.’ Prior to the widespread use of Hib vaccine, H. influenzae was the most common cause of meningitis in children up to 5 years of age and used to be the most frequent cause of acquired deafness in children. Although extremely rare now, Hemophilus meningitis is contagious and is a significant risk to un-immunized children.

Meningococcal meningitis is caused by the bacterium Neisseria meningitidis, also referred to as the ‘The Meningococcus’ bacteria. N. meningitidis is a frequent cause of meningitis in infants and the main cause of meningitis in older children and young adults. It is often associated with outbreaks or clusters of meningitis illness in schools, camps, and large gatherings of people. Although meningococcal meningitis is quite rare, occurring at a rate of less than one case per 100,000 people per year, it causes severe disability and often death. The low rate of illness due to meningococcus is surprising, especially considering the fact that at any given time, 5 to 10 percent of the population may carry meningococcus in their nose and throat. Meningococcus is contagious, being spread from person to person by the exchange of saliva.

A vaccine is available for the prevention of disease due to most strains of N. meningitidis. It is routinely recommended for children in the 11-12 year old age range and for entering college students who have not previously been vaccinated. The vaccine is relatively ineffective for children under 2 years of age. The duration of immunity from the meningococcal vaccine, perhaps lasting only 3-5 years, is also fairly low compared to other vaccines.

Meningitis, from any cause, is rare in Whitman County. Unfortunately, in the last four months there have been two cases of illness due to N. meningitidis. Both cases occurred in first year Washington State University students and both were the same Type Y strain. It is unusual to have two cases of meningococcal disease in a year, let alone two cases of the same type over a 4 month period. But even more mysterious is that both students were vaccinated against meningococcal meningitis only three years ago.

The threshold for declaring an outbreak or epidemic of meningococcal illness is three cases occurring in three months in a well defined population like a school or a university. Two cases in four months falls short of meeting this definition, but it is cause for concern nonetheless.

In response to the recent cases of meningococcal disease, WSU has initiated a campaign to make students more aware of the signs and symptoms of meningitis. Students are asked to take steps to limit the transmission of bacteria from person to person through frequent hand washing and avoidance of sharing items like cups, water bottles, eating utensils and smoking materials. WSU officials, in concert with the Whitman County Health Department, are also encouraging students to consider vaccination as an additional measure to reduce the chance of infection. See the WSU Health and Wellness page for more information (http://hws.wsu.ed/default.asp?PageID=4927).

Meningitis may still be a mystery in some respects, but we can protect ourselves by getting the appropriate vaccination at the right time, knowing the signs and symptoms of meningitis, and adopting simple hygienic measures. For more information on meningitis, contact the Whitman County Health Department or visit these excellent web resources:

http://www.cdc.gov/meningitis/index.html

http://www.doh.wa.gov/cfh/immunize/diseases/meningitis/default.htm

http://www.meningitisfoundationofamerica.org/templates/