Atacora and Borgou in northern Benin are the most affected d partements and the Ministry of Health in these d partements is launching a mass vaccination campaign. The African meningitis belt is the area between Senegal and Ethiopia and includes all or part of at least 15 countries, with an estimated total population of approximately 300 million. The current epidemic is however of a larger extent, threatening to affect wide ranges of the population if mass vaccination campaigns are not carried out. There exist various forms of meningitis, but meningococcal meningitis is the only form of bacterial meningitis, which causes epidemics. Transmission is by direct contact, including respiratory droplets from nose and throat of infected persons.
Most infections are subclinical and many infected people become symptomless carriers.
Waning immunity among the population against a particular strain favours epidemics, as do overcrowding and climatic conditions such as dry season or prolonged drought and dust storms. Meningococcal meningitis is characterized by sudden onset of intense headache, fever, nausea, vomiting, photophobia, and stiff neck. Infants may have illness without sudden onset and stiff neck. The incubation period is between two and ten days, mostly three to four days. Texts and graphics may be reproduced freely, under the condition that their origin is clearly referred to, see Conditions .