Traditional Summary of Meningitis Outbreaks across the World from 1905 to 2016

The review of the literature of meningitis outbreaks recorded throughout the world shows us that meningitis is present on all 5 continents. Meningococcal meningitis is a global public health problem. Its incidence is variable: low in Europe and North America (1 case for 100,000), but high in Africa (800 to 1000 cases per 100,000) during epidemic outbreaks [1]. The history of meningitis dates back to 1805 in Geneva, then to the nineteenth century through Europe and North America, reaching Africa in 1840. Since then, the African continent remains the most affected by epidemics of bacterial meningitis. It is probably by the military garrisons from Europe that the bacteria have arrived on the African continent [2]. French troops based in Algeria experienced two major outbreaks in 1840 and 1847, as British troops in Egypt in 1889 and in Sudan in 1899 [3]. The first widespread manifestations of East-West from 1905 (Sudan), 1906 (Ghana), from 1914 (Sudan), 1919 (Ghana), affecting Nigeria and Niger. The progression is towards the north, then to the west Kordofan is reached in 1934, Darfur in 1936, Chad in 1936, as many cases of meningitis on both sides of the (theoretical) border in 1936, Then it was the turn of Upper Volta and Ghana in 1939, Mali in 1940 and Dakar in 1941 [4]. Epidemics occur almost as annually, according to the WHO definition of an epidemic year. A cumulative incidence greater than 100 cases per 100,000 populations, nationally [5]. The chronology outbreaks of bacterial meningitis having occurred in the world in general and in particular in the African meningitis belt from 1905 to 2016 are summarized in Table 1 [4,6-10]. Between 1995 and 1997, epidemics were the most important epidemics that Africa has ever experienced: more than 250,000 cases have been reported. Due to meningococcal A ST-5 of clone complex 5 (cc5), they start in 1995 in Niger (26,738 cases). In 1996, an epidemic peak of exceptional amplitude, with more than 150,000 reported cases, affected Burkina Faso (42,129 cases), Mali (7,244 cases), Niger (16,050 cases) and Nigeria (75,069 cases). This epidemic will continue in 1997, Burkina Faso (21,504 cases) and Mali (10,960 cases), followed by Ghana (18,551 cases), Togo (2,845 cases) and The Gambia 913 cases), while in Niger the number of cases is clearly decreased (3,922 cases). Year after year, all countries in the belt will be affected by A meningococci belonging to this clone [4]. The bacteria involved in meningococcal meningitis are Neisseria meningitidis. It is recognized as the most responsible bacterium for meningitis epidemics in Africa. There are 13 serogroups of Neisseria meningitidis and most invasive infections are due to 6 serogroups: A, B, C, X, Y and W135. Serogroup A was considered until 2010 to be hyperendemic in the meningitis belt. It is now sharply reduced by the introduction of conjugate vaccine A [11]. Serogroup W135 is present in all countries in the meningitis belt and has been on the increase since vaccination against serogroup A [12]. Serougroup X was mainly responsible for the epidemics in Niger, Kenya and Uganda [13]. In 2015, an epidemic of serogroup C meningitis is observed in Niger and other countries in the meningitis belt [6].


Introduction
The review of the literature of meningitis outbreaks recorded throughout the world shows us that meningitis is present on all 5 continents. Meningococcal meningitis is a global public health problem. Its incidence is variable: low in Europe and North America (1 case for 100,000), but high in Africa (800 to 1000 cases per 100,000) during epidemic outbreaks [1]. The history of meningitis dates back to 1805 in Geneva, then to the nineteenth century through Europe and North America, reaching Africa in 1840. Since then, the African continent remains the most affected by epidemics of bacterial meningitis. It is probably by the military garrisons from Europe that the bacteria have arrived on the African continent [2]. French troops based in Algeria experienced two major outbreaks in 1840 and 1847, as British troops in Egypt in 1889 and in Sudan in 1899 [3]. The [4]. Epidemics occur almost as annually, according to the WHO definition of an epidemic year. A cumulative incidence greater than 100 cases per 100,000 populations, nationally [5]. The chronology outbreaks of bacterial meningitis having occurred in the world in general and in particular in the African meningitis belt from 1905 to 2016 are summarized in Table 1 [4,[6][7][8][9][10]. Between 1995 and 1997, epidemics were the most important epidemics that Africa has ever experienced: more than 250,000 cases have been reported. Due to meningococcal A ST-5 of clone complex 5 (cc5), they start in 1995 in Niger (26,738 cases). In 1996, an epidemic peak of exceptional amplitude, with more than 150,000 reported cases, affected Burkina Faso (42,129 cases), Mali (7,244 cases), Niger (16,050 cases) and Nigeria (75,069 cases). This epidemic will continue in 1997, Burkina Faso (21,504 cases) and Mali (10,960 cases), followed by Ghana (18,551 cases), Togo (2,845 cases) and The Gambia 913 cases), while in Niger the number of cases is clearly decreased (3,922 cases).
Year after year, all countries in the belt will be affected by A meningococci belonging to this clone [4]. The bacteria involved in meningococcal meningitis are Neisseria meningitidis. It is recognized as the most responsible bacterium for meningitis epidemics in Africa. There are 13 serogroups of Neisseria meningitidis and most invasive infections are due to 6 serogroups: A, B, C, X, Y and W135. Serogroup A was considered until 2010 to be hyperendemic in the meningitis belt. It is now sharply reduced by the introduction of conjugate vaccine A [11]. Serogroup W135 is present in all countries in the meningitis belt and has been on the increase since vaccination against serogroup A [12]. Serougroup X was mainly responsible for the epidemics in Niger, Kenya and Uganda [13]. In 2015, an epidemic of serogroup C meningitis is observed in Niger and other countries in the meningitis belt [6].
The evolution of meningococcal serogroups through the epidemics recorded from 1950 to 2016 is summarized in Table 2 [4,[6][7][8][9][10]13]. These data show that meningitis occurs almost everywhere in the world, but to varying degrees depending on the climate and period.
The American, Asian, European and Oceanic continents are less affected compared to the African continent [2,14,15]. In Africa, this is the so-called "African meningitis belt" where the majority of cases of meningitis are recorded. It extends from Senegal to Ethiopia and covers 26 countries [16]. Meningitis is one of the pathologies that have caused human suffering for centuries [14,15]. Since 1905, meningitis has become a public health problem in the world, especially epidemics of meningococcal meningitis A (Neisseria meningitidis A) until the introduction of conjugate vaccine A "MenAfriVac" in 2010 in the African meningitis belt [2,17]. In 1970 there was the appearance of new strains: The first was Neisseria meningitidis B in some countries of America, Europe, Asia and an African country, namely Algeria [2,14,15]; Second was the Neisseria meningitidis C in Africa, America, Asia and Europe [2,14]. It has been the cause of the recent epidemic in Niger

Conclusion
These results show the dynamics of the epidemiological monitoring in Mali in all its components with a major observation, the reduction of epidemics on a large scale substituted by sporadic or endemic forms at the pediatric level. The introduction of A-conjugate vaccine could be an alternative to Mali because NmA has almost disappeared but replaced by other serogroups including NmW135, NmC and NmX. We believe that the use of vaccines against S. pneumoniae and Hib under the Expanded Program for Immunization (EPI) would prevent significant endemic morbidity and many deaths due to meningitis. However, it would be necessary to improve some points: Control of emerging meningococcal serogroups; case-by-case monitoring at all levels of the health pyramid; the number of serotypes covered by vaccines. Sudan