Between 1 November 2022 and 27 January 2023, a total of 559 cases of Meningitis (of which 111 have been laboratory confirmed), including 18 deaths (an overall fatality rate of 3.2%), have been reported from Zinder Region, southeast of Niger, according to a press release issued by the World Health Organization on 8 February 2023. This compares to 231 cases reported during the period 1 November 2021 to 31 January 2022. The majority of laboratory-confirmed cases are due to infections by the Bacterium Neisseria meningitidis serogroup C. Reactive vaccination campaigns with the trivalent ACW meningococcal polysaccharide vaccine have been implemented.
Niger is located largely in the African Meningitis Belt with seasonal outbreaks recurring every year. However, the ongoing outbreak shows both an increased number of cases and an increased growth rate compared to the previous seasons.
The Zinder Region shares an international border with Jigawa State in Nigeria where a Neisseria meningitidis serogroup C outbreak is also ongoing, confirming the risk of international spread. Moreover, the simultaneous occurrence of other epidemics, insecurity and population displacement, all in the context of a protracted humanitarian crisis, are likely to contribute to the spread of the outbreak in other countries of the West African subregion.
The World Health Organization assesses the risk posed by the current Meningitis outbreak in Niger as high at the national level, moderate at the regional level, and low at the global level. Being located in the African meningitis belt, Niger has been affected by repeated Meningitis epidemics resulting in 20 789 cases and 1369 deaths reported since 2015.
Epicurve of cases of Meningitis reported in Niger by month, 1 October 2021 - 27 January 2023. World Health Organization.
Two hundred and twenty eight samples collected from patients showing symptoms consistent with Meningitis, 154 (67.5%) of which have subsequently been analyzed bythe Center for Medical and Health Research in Niamy. Neisseria meningitidis serogroup C was identified in 93.7% of confirmed cases (104 individual cases), followed by Streptococcus pneumoniae (five cases, or 4.5% of the total) and Haemophilus influenzae (two cases or 1.8% of the total). The remaining 43 samples tested negative.
Fifty three percent of all the cases were male, with 96.3% of cases (or 538 individual cases) being under 20, with 202 cases (36.2%) reported in the 10-14 years age group, followed by the 5-9 years age group with 153 cases (27.4%), the 15-19 years age group with 107 cases (19.1%), and the 0-4 years age group with 76 cases (13.6%).
The most affected health district in Zinder Region is Dungass (342 cases, 6 deaths), followed by Matamèye (98 cases, 3 deaths), Mirriah (72 cases, 3 deaths), Magaria (38 cases, 5 deaths), Zinder ville (7 cases, 1 death) and Gouré (2 cases, 0 deaths).
Distribution of reported meningitis cases by health district, Zinder region, Niger, 1 November 2022-27 January 2023. World Health Organization.
Meningitis is a serious infection of the meninges, the membranes covering the brain and spinal cord. Several different Bacteria can cause Meningitis, however, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis (sometimes spelled Neisseria meningitis) are the most frequent ones, and are transmitted from person to person through droplets of respiratory or throat secretions from infected people.
Neisseria meningitides is a form of Betaproteobacteria. A total of 12 serogroups of Neisseria meningitides have been identified, six of which (A, B, C, W, X and Y) can cause Meningococcal Meningitis epidemics.
The average incubation period is 4 days but can range between 2 and 10 days. The most common symptoms of Meningitis are a stiff neck, high fever, sensitivity to light, confusion, headaches and vomiting. Even with early diagnosis and adequate treatment, 5% to 10% of patients die, typically within 24 to 48 hours after the onset of symptoms. Bacterial Meningitis may result in brain damage, hearing loss or a learning disability in 10% to 20% of survivors. A less common, but even more severe (and often fatal), form of Meningococcal Disease is Meningococcal Septicaemia, which is characterized by a haemorrhagic rash and rapid circulatory collapse.
The highest burden of disease is seen in a region of sub-Saharan Africa, known as the African Meningitis Belt, which is especially recognised to be at high risk of Meningococcal but also Pneumococcal Meningitis epidemics.
iger is located largely in the African Meningitis Belt, where Meningitis epidemics typically follow a seasonal pattern (usually from January to June), with a size that varies from year to year. In 2015, a large Meningitis outbreak attributed to Neisseria meningitidis serogroup C occurred, affecting nearly 10 000 people. In 2009 and 2006, meningitis outbreaks caused by Neisseria meningitidis serogroups A and X, respectively, were also reported. Haemophilus influenzae and Streptococcus pneumoniae are two other important pathogens that contribute significantly to the Bacterial Meningitis burden within Niger.
Licensed vaccines against Meningococcal, Pneumococcal and Haemophilus influenzae diseases have been available for many years. These Bacteria have several different strains (known as serotypes or serogroups) and vaccines are designed to protect against the most harmful strains. Over time, there have been major improvements in strain coverage and vaccine availability, but no universal vaccine against these infections exists.
In the African Meningitis Belt, Meningococcus serogroup A accounted for 80–85% of Meningitis epidemics before the introduction of a meningococcal A conjugate vaccine through mass preventive campaigns (since 2010) and into routine immunization programmes (since 2016). Among vaccinated populations, incidence of serogroup A Meningitis has declined by more than 99%, and no serogroup A case has been confirmed since 2017.
However, cases of Meningitis and outbreaks due to other Meningococcal serogroups, apart from serogroup B, continue to strike.
The ongoing outbreak shows both an increased number of cases and an increased growth rate compared to the previous seasons. Moreover, the Meningitis epidemic season (usually from January to June, marked by high temperatures and dry winds combined with heavy dust, a period known as the harmattan), the mixing of populations, the simultaneous occurrence of other epidemics in the same region (Measles, Diphtheria and COVID-19), insecurity and population displacement, all in the context of a protracted Humanitarian crisis, are likely to contribute to the spread of the outbreak.
The Zinder region borders Jigawa State in Nigeria, where a Neisseria meningitidis serogroup C outbreak is also ongoing, confirming the risk of international spread to other countries of the West African subregion. The World Health Organization assesses the risk posed by the current Meningitis outbreak in Niger as high at the national level, moderate at the regional level, and low at the global level.
Meningococcal Meningitis remains a public health concern with a high case fatality rate and leading to serious long-term complications.
Preventing Meningitis through vaccination is the most effective way to reduce the burden and impact of the disease by delivering long-lasting protection. The rollout of multivalent meningococcal conjugate vaccines is a public health priority to eliminate Bacterial Meningitis epidemics in the African Meningitis Belt. Introduction into routine immunization programmes and maintaining high coverage will be critical to avoid the resurgence of epidemics.
Antibiotics for close contacts of Meningococcal cases, when given promptly, decrease the risk of transmission. Outside the African Meningitis Belt, chemoprophylaxis is recommended for close contacts within the household. Within the Meningitis Belt, chemoprophylaxis for close contacts is recommended in non-epidemic situations. Ciprofloxacin is the antibiotic of choice, and ceftriaxone an alternative.
Admission to a hospital or health centre is necessary. Isolation of the patient is not usually advised after 24 hours of treatment.
Appropriate antibiotic treatment must be started as soon as possible. Ideally, lumbar puncture should be done first as antibiotics can make it more difficult to grow Bacteria from the spinal fluid. However, blood sampling can also help to identify the cause and the priority is to start treatment without delay. A range of antibiotics is used to treat Meningitis, including penicillin, ampicillin, and ceftriaxone. During epidemics of Meningococcal and Pneumococcal Meningitis, ceftriaxone is the drug of choice.
The response to epidemics consists of appropriate case management, active community-based case-finding and reactive mass vaccination of affected populations. Surveillance, from case detection to investigation and laboratory confirmation is essential to the control of Meningitis.
Reactive vaccination campaigns have been implemented in Zinder region, and monitoring the spread to new areas is crucial to guide further response activities, including considering further vaccine requests if appropriate. Timeliness of the reactive campaign is critical, ideally within four weeks of crossing the epidemic threshold.
The World Health Organization does not recommend any restriction on travel and trade to Niger on the basis of the information available on the current event.
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