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Meningococci: Bacteria with epidemic potential

Gudrun Heise | Julia Vergin
September 1, 2023

Meningococcus is the most common cause of bacterial meningitis worldwide. And as the recent outbreak in the United States shows, it can be life-threatening.

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Bakterien Neisseria meningitidis Meningokokken
Image: CAVALLINI JAMES/BSIP/picture alliance

Health authorities in the US state of Virginia have registered a "statewide meningococcal outbreak." Since June 2022, 30 people have fallen ill — three times more than normal within such a period, it said. Five people have died from complications of a "rare but serious illness," according to a statement from the Department of Health.

Meningococci are dangerous for immunocompromised persons

About one in 10 adults carries the meningococcal bacteria (Neisseria meningitidis). Meningococci are divided into at least 12 so-called serogroups, five of which are the cause of most diseases: A, B, C, W and Y. Serogroup "B" is the most frequently diagnosed, at 66%.

As long as the immune system is strong and the protection from childhood vaccinations is still working, the infection goes unnoticed. However, if the disease breaks out, it can result in damage to the brain, hearing loss or cognitive impairment.

How does the immune system work?

Meningitis is a frequent consequence of meningococcal infection

In two-thirds of all cases, the disease progresses as meningitis. According to the World Health Organization (WHO), meningococci are the most common cause of bacterial meningitis. Especially in sub-Saharan Africa,epidemics occur repeatedly with incidence rates of up to 1,000 cases per 100,000 inhabitants.

Sepsis, or blood poisoning, can also be the result of an infection. In some cases, it can require a limb amputation. Such serious consequences occur in about one in five of those infected.

And about 10% of meningococcal infections are fatal.

How to recognize sepsis

Spread of meningococci through droplets

Meningococci settle in the throat and nasal cavity. The incubation period is between three and four days, but in some cases between two and ten days. 

Just by coughing, sneezing or shaking hands, meningococci can be transmitted from one infected person to another via droplets. Kissing can also transmit it. Carriers are infectious and can pass on the bacteria even if they do not grow sick themselves.

The initial symptoms are usually non-specific. Often, they resemble a flu or a flu-like infection. Then comes high fever, sensitivity to light and neck stiffness. There may also be bleeding in the skin, usually starting on the legs.

The meningococcal vaccine protects people

Infants and young children are particularly at risk of contracting meningococcal disease because their immune system is not yet as robust as that of an adult.

People who live together in confined spaces, such as small apartments, mass shelters or refugee camps, are also at high risk because of the way the bacteria spread.

The WHO recommends following hygiene measures to help prevention efforts, including regular hand-washing, as well as getting vaccinated.

Edited by: Derrick Williams

This article has been translated from German.

DW journalist Julia Vergin
Julia Vergin Senior editor and team lead for Science online