Meningitis

What is Meningitis?

Meningitis (inflammation of the linings of the brain) can be caused by many types of organisms, such as bacteria and viruses.

Meningococcal meningitis is caused by a specific bacterium known as N. meningitides.  In addition to several types of N. meningitidis, another common bacterium that can cause meningitis is called Streptococcus pneumoniae.  There are 83 known types of Streptococcus pneumoniae.  Usually this streptococcus bacteria causes pneumonia in the lungs.  However, this organism may spread through the blood to infect the linings of the brain.

In countries where the disease is common, up to 5 to 10 percent of the general population will carry the N. meningitidis bacterium in their nose or throats.

Another form of meningitis is called aseptic meningitis. The most common cause of aseptic meningitis is a viral infection, and enteroviruses are common causes of viral meningitis, especially in children during the summer months. However, aseptic meningitis may be caused by other viruses, such as arboviruses, HIV, herpes simplex virus (HSV) types 1 and 2, some bacteria, fungi, and parasites. Most people who get infected with enteroviruses are asymptomatic or have only a general febrile illness.

How do you get Meningitis?

Person-to-person transmission occurs by inhaling respiratory droplets containing the bacteria or virus or by close contact with an infected person's respiratory secretions or saliva.

Enteroviruses are most often spread via the fecal-oral route from person to person through fecal contamination of water or food or contact with contaminated inanimate objects. Enteroviruses can also be spread through respiratory secretions (saliva, sputum, or nasal mucus) of an infected person

Susceptibility and Resistance

General susceptibility is low.  The disease is most common in very young children or young adults.  Excessive crowding contributes to the spread of bacterial meningitis.  Susceptibility generally decreases with age.

Incubation Period

The incubation period for Meningitis is 3-10 days.

What are the Symptoms?

The illness usually involves the sudden onset of fever, severe headache, a stiff neck, nausea with some vomiting, and may be accompanied by a small rash.  The patient may become confused and delirious and enter into a coma, sometimes very quickly after the onset of the illness.  Unless the illness is diagnosed early and treated rapidly and aggressively with antibiotics and other supportive measures, the fatality rate can be quite high.  With early and aggressive treatment with antibiotics for bacterial meningitis, the death rate has been reduced to between 5 and 15 percent.

Antibiotics are not effective for aseptic meningitis caused by viruses. However, most people who get infected with enteroviruses are asymptomatic or have only a general febrile illness.

Preventative Measures

Vaccination against meningitis caused by the bacteria, N. meningiditis, is recommended for people who travel or reside in the countries where epidemics occur, i.e. sub-Saharan Africa.  Vaccination may also be recommended when there are many cases or an outbreak of this bacteria in other areas.

For people who have been in direct contact with persons with bacterial meningitis, antibiotics (rifampin, ciprofloxacin, and ceftriaxone) are recommended for prevention of the disease for exposed persons.

Following general food and water precautions and maintaining careful personal hygiene will help prevent aseptic meningitis caused by enteroviruses.

Treatment

Early and aggressive treatment with a variety of commonly available antibiotics is generally effective. For aseptic meningitis, only general supportive measures are available.

Medications

Vaccinations

Where Does It Commonly Occur?

Meningococcal infections are found just about anywhere in the world and cases are generally sporadic. The sub-Saharan countries of Africa regularly experience epidemics of bacterial meningitis during the dry season, usually from December through April. These countries are known as the sub-Saharan meningitis belt and include The Gambia, Senegal, Mali, Burkina Faso, Ghana, Niger, Nigeria, Cameroon, Chad, Central African Republic, Sudan, Uganda, Kenya, Ethiopia, and Eritrea.

Enteroviruses that are the main cause of aseptic meningitis are found worldwide.