Meningococcal meningitis


Meningococcal meningitis is an infection caused by a bacterium, which causes inflammation of the membranes covering the brain and spinal cord. Meningococcal disease is primarily an early childhood infection, but also affects adolescents and adults. Meningococcal infections occur worldwide. The causative organism, N. meningitidis bacteria (Meningococcus), is normally found in the nasopharnyx (throat) in about 5% of healthy individuals and does not cause disease. The Meningococcus continues to be a leading cause of bacterial meningitis and septicemia. It is cyclic, occuring yearly, with occasional localized outbreaks.


The way N. meningitidis bacteria enter the body is through the upper respiratory tract. People can acquire the disease by inhaling the bacteria (when an infected person coughs on them, for example), by direct mouth-to-mouth contact with an infected person, or by indirect contact (for example, by touching one's nose after touching an object or a hand that was recently contaminated with an infected person's nasal secretions).


Symptoms and disease course

The majority of persons who become infected develop very mild upper-respiratory symptoms or no symptoms at all. More serious cases occur when the bacteria succeed in invading through surface tissues and entering the bloodstream and/or other parts of the body. This most often takes 1 of 3 forms, which may or may not occur one after the other:

Subacute meningococcemia

Symptoms appear suddenly and include fever, chills, headache, body ache, nausea, vomiting, drowsiness, and a body rash that at first may look like faint pink "rose spots" or hives and later may develop into petechiae (tiny red dots that are pinprick to pinhead size).

Acute meningococcemia

Symptoms again appear suddenly, but are much more intense and can progress rapidly. The headache is severe and the chills shaking. In cases where the bloodstream is heavily invaded, very large, dark reddish-purple blotches appear as blood seeps out of damaged vessels into the skin; circulatory collapse can occur. In cases where the brain is invaded, the infected person may fall into a coma.


While this is not the most common form of meningococcal infection, it is the most classic. Meningitis occurs when the bacteria invade the membranes lining the spinal cord and brain. The neck and spine become rigid, and attempts to flex one's head backward and forward are painful. The inflammation causes increased pressure, which can result in severe headache, nausea, vomiting, dilated pupils and, in severely ill infants, a bulging of the fontanelles (although mildly ill infants may display only fever, vomiting, diarrhea and irritability). Progression of the disease may result in delirium, convulsions, coma and death.


Disease Risk

This disease is world-wide. It is most common in poor, overcrowded areas and seems to have a seasonal increase in winter and spring. It can occur at any age, but it is most common in children younger than 5 years; however, half of all cases occur in persons aged 2 years and older during epidemics. Older adults are also at increased risk.

Meningococcal meningitis is the only form of bacterial meningitis which causes epidemics. The largest epidemics of meningococcal meningitis have been reported in sub-Saharan African countries within the meningitis belt -- across the middle of Africa -- especially during the December-June dry season, but epidemic meningococcal disease can occur in any country regardless of climate.

Countries in sub-saharan Africa have experienced large outbreaks every 8-12 years in the past, but intervals between major epidemics have become shorter and more irregular since the beginning of the 1980s. The possibility of a new epidemic cycle in the mid-1990s, noted with outbreaks in 1995 (e.g. Cameroon, Niger), seems to be confirmed by the outbreaks now reported in Burkina Faso and Nigeria.

Epidemics have also occured on an irregular basis in Burundi, Kenya, Tanzania, northern India, Nepal and other countries. Large outbreaks have been reported in Ethiopia and Brazil.

Travelers to any of these areas are at increased risk, especially if they have prolonged or intimate contact with the local population. Persons without a working spleen are especially at risk, as are persons with a certain deficiency in their blood's immune system.


Primary Protection Measures

The only reasonable precaution travelers at risk may take to avoid contracting this disease (other than vaccination) is to stay away from crowded areas frequented by local inhabitants, to avoid other close physical contact, and to wash their hands after touching hands or objects that may possibly be contaminated with nasal secretions.



The vaccine for meningococcal meningitis is an injectable, inactivated-bacteria vaccine. Vaccination is recommended for some travelers to countries recognized as having epidemic meningococcal disease, especially if they will have prolonged or intimate contact with the local populace. You should consider the vaccine if you will be traveling to sub-Saharan Africa, especially during the dry season (December to June), and/or to Burundi, Kenya, Tanzania, Nepal or New Delhi (India) at any time during the year.



Because invasive meningococcal disease can progress rapidly into fatalities, early detection and prompt, intensive treatment with antibiotics are extremely important.

A person with meningococcal meningitis can transmit the disease as long as symptoms persist (or until 24 hours after effective treatment was begun), and carriers without symptoms can transmit the disease for about 6 months.

Antimicrobial therapy must be started immediately. Penicillin is prescribed and is given intravenously for this disease. Intravenous mannitol can be used to treat the complications arising from the increased intracerebral pressure. Sometimes systemic corticosteroids are used.

The death rate ranges from 5% to 15%; with young children and adults over 50 having the highest death rate.