MENINGITIS OUTBREAK IN SUBSAHARAN AFRICA; A SYNOPSIS
BY: IYOKE UYIOSE O. & ODERINDE IYANUOLUWA T.
AUTHORS AS AT TIME OF WRITING: 3RD YEAR CLINICAL STUDENTS, COLLEGE OF MEDICINE, UNIVERSITY OF IBADAN.
IYOKE UO, ODERINDE IT
Department of Medicine and Surgery
College of Medicine
University of Ibadan
In the Sub-Saharan African region, the meningitis belt which comprises of 26 countries has been plagued for over 100 years with recurrent outbreaks of meningitis superimposed on an established endemicity, resulting in significant health and economic burden on affected countries. This article seeks to review literature in an attempt to provide a historical perspective, explore relative risks and challenges across the countries within the belt and proffer possible strategies to improve control of epidemics and outbreaks in the belt.
Keywords: Meningitis, Outbreak, Sub-Saharan Africa, African Meningitis belt
Meningitis, an acute inflammatory condition of the meninges, is a debilitating disease characterized by symptoms such as fever, neck stiffness, photophobia, altered mental status. It is caused by various microorganisms (bacteria, viruses, fungi, parasites) with bacterial and viral meningitides being the most contagious1. Meningococcal disease, a contagious bacterial disease is the only known cause of epidemics1-2. Transmission occurs via direct contact with respiratory droplets and aerosols from nose and throats of infected individuals1.
Cases occur sporadically in the west including the US and Europe with incidences ranging from 3-100 per 100000 inhabitants annually2. It is however endemic in the African region particularly across the meningitis belt where incidence rates are as high as 1000 cases per 100000 inhabitants annually2.
THE AFRICAN MENINGITIS BELT
The African Meningitis Belt (AMB), with an estimated population exceeding 400 million people was originally described by Lapeysonnie in 1963 and redefined in 19871,3. The belt stretches from Senegal in the West to Ethiopia in the East of Africa and contains 26 countries; the WHO also refers to the region as the Extended Meningitis Belt1,4. This is because historically; looking at the past 100 years, high rates were present in about 16 countries but in recent times there has been an extension further south. Countries in the AMB include: Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Côte d’Ivoire, Democratic Republic of Congo, Eritrea, Ethiopia, The Gambia, Ghana, Guinea, Guinea Bissau, Kenya, Mali, Mauritania, Niger, Nigeria, Rwanda, Senegal, South Sudan, Sudan, Tanzania, Togo and Uganda1,4.
Figure 1: Countries within the meningitis belt 22
The AMB designation was sparked by the distinct epidemiological picture observed in bacterial meningitis outbreaks in the region. The region has the highest annual incidence of meningococcal meningitis in the world with superimposed frequent epidemics that constitute a major public health burden4-7.
The most affected countries include Niger, Ethiopia, Chad and Burkina Faso that together account for 65% of the cases in Africa1.
Epidemics within this region occur every 5-12 years with attack rates ranging from 100-800 people per 100,000 to as high as 1% in some communities with children having the highest attack rates during epidemics1,7. Case fatality rates vacillate around 10% despite adequate and appropriate interventions, and 10-15% of affected individuals suffer enduring neurological sequelae e.g. deafness, seizures etc 1,8. In recent times, the epidemics have been occurring sooner and more sporadically8.
Outbreaks within this region occur largely during the hot and dry season indicating that the characteristic climatic conditions of the belt are an important predisposing factor to meningitis epidemics1,4. Local and international travels also favour the spread of virulent strains of meningococci4. Other identified predisposing factors include poor living conditions, overcrowding, and increasing number of internally displaced persons from insurgencies and acts of terrorism4.
THE AFRICAN MENINGITIS BELT; MARKING TIME11-16
The earliest records of meningitis are neither linked to the AMB or Africa. Some notable ancient records dating before the 19th century are found in Greek manuscripts written by Hippocrates and other persons11,15. However, the first reported outbreak occurred in Geneva, Switzerland in 1805 and several epidemics in the United States and Europe followed11. The disease was first linked to a bacterial cause; Neisseria meningitidis in 188711,15, subsequently other causative organisms including streptococcus pnemoniae and Haemophilus influenzae were discovered.
The first outbreak in Africa occurred in 18408, and then outbreaks became more common in the 1900s15.
The 19th Century
This marked a period when the dust of meningitis outbreaks was raised in Africa and it began to find a place to settle. It started with the 1840 outbreak in Algeria11.
The 1840 Outbreak
This occurred in Algeria amongst a French garrison after which it spread to civilians in nearby towns. French troops frequented the country due to colonization by France15. The disease was also found amongst many other French troops around the world. For about a decade before the outbreak, relatively little was heard about meningitis as the disease had calmed in the west since the outbreaks that followed the 1805 epidemic in Geneva8. The epidemic in Algeria would last till 1847 and cause many deaths among the indigenous population as well. Details on the outcome and interventions made are sparse11,13.
This event illustrates the significance of tourism, travel, social and political instability in the spread. This was a theme that recurred throughout the 20th century especially during the world war.
Following this, over 400 outbreaks occurred at subnational levels all over the continent in the following decades up to the 21st century. The outbreaks were not evenly distributed across the continent as they mainly occurred in the Sahel districts. Epidemics across the continent were similar with occurrences in the West although often with higher incidence and fatality rates15.
Scattered cases were reported in this period in South Africa. Mining compounds had favourable conditions for meningitis, with newly hired African workers forced to live in conditions similar to those of military recruits.
Figure 2: Pictorial depiction of events in the 19th and 20th century5
The 20th century
This period witnessed the hugest surges of meningitis in Africa and a polarize to the Sub-sahara and the AMB11-17.
The initial area for the epidemic CSM, however, was the savanna zone south of the Sahara Desert from Sudan to Senegal. This area was swept by a series of great epidemics during the century 15.
The 1905 Epidemic
The first of the great African epidemics began in Northern Nigeria in early 190515,16. It spread westward as far as Mali and northwest Ghana in 1906, enduring in those places until rains came in 1908. Total deaths were not known but have been guessed to reach 34,000 in Ghana; case mortality was estimated at 80 percent15. Although there are no clear records due to ill medical and political systems, there clearly was a major disaster in this period.
By 1910 it was established that the meningococcus was solely responsible for epidemics and that other bacteria rather cause sporadic cases13,15-16.
In the West, there was some success in vaccination against diphtheria during this time, hence numerous efforts were made to develop a therapeutic serum and active vaccines against meningococcal meningitis15. Four serotypes were discovered due to varied vaccination successes15.
Epidemiologists posit that pilgrims and/or soldiers infected in Sudan imported the disease to Northern Nigeria14. The month it would have taken soldiers and pilgrims to travel from Sudan to northern Nigeria by camel would likely have been within the time period that the microorganisms remained alive in the nasopharynx of the travelers. The disease was notorious for asymptomatic carriage11-15.
The Second CSM Cycle
After the 1905 outbreak, subsequent large and deadly outbreaks tended to occur every 5-10 years, usually during the winter months of the meningitis belt2,16. The second cycle started in northwest Ghana in 1919, spread to Burkina Faso in 1920, and swept northern Nigeria and Niger from 1921 to 19241. Weak political and medical infrastructures impeded accurate estimates of cases or deaths, nonetheless the death toll in one northern Nigerian province, Sokoto, was put at over 45,000 in 1921 alone, and it is assumed that over the 4-year period at least 15,000 persons died in Niger15.
Around this time there was development of the group A vaccine15.
Some challenges encountered was difficulty of the Europeans in introducing the vaccines to affected regions. Natives of affected regions rebelled against moves made by the colonial medical authorities as they had previously imposed harsh measures of isolation on communities and households. Households tended to hide their affected members to avoid the surveillance radar15.
The 3rd CSM cycle
This started in West Africa in 1935. Chad was attacked by an epidemic which was noticed to be to an outbreak that occurred during the previous year in some provinces in Central Sudan. This was the first time that a clear pattern of east-west spread from Sudan was demonstrated. Carriers brought infection westward during the rainy seasons to Chad, to northern Nigeria, and thence to Niger, with disastrous epidemics following. This contributed to the discovery of the important epidemiological role of asymptomatic carriers16.
This CSM outbreak hit Burkina Faso, Mali and northern Ghana in 1938-1939. Local outbreaks continued through 1941. Mortality statistics are very unreliable, majorly due to poor health systems and households/communities avoiding the surveillance systems of colonial masters. There was a breakthrough against the disease with the advent of sulfa and penicillin drugs, the sulfa drugs reduced mortality from 50-80% to 20% but still several tens of thousands died. French efforts to protect Africans against serogroup A by vaccination had inconclusive results, and similar British trials in Sudan were unsuccessful11-13.
CSM remained epidemic for close to 10 years after across the belt. Major outbreaks where continually reported from Chad to Senegal. Burkina Faso, western Niger, and northwest Ghana were particularly afflicted.
The disease with the outbreaks had fairly settled in the region. More cycles of epidemics developed in 1949 from foci in northern Ghana, northern Nigeria, and Burkina Faso, spreading eastward as far as Sudan by 1952. Geographic patterns of spread became much less distinct.
Between 1905 and 1960, epidemiologists speculate that up to a million or more-people died of CSM in the belt, especially in West Africa.
In 1996, a large epidemic was recorded which killed 25000 in Africa2,5,7
RISK ACROSS COUNTRIES IN THE BELT
Dusty and dry environments are strong predictors of meningococcal epidemics. It is hypothesized that inhaled dust particles cause small cuts the mucous membranes, allowing N. meningitidis microbes residing in the throat get into the bloodstream and underlying tissues, causing infection9,10,20.
Meningococcal epidemics usually cease with the onset of wet/rainy season. They tend to occur in places that have a distinct wet season in addition to a dry season. Meningococcal epidemics are less likely in deserts and humid forests9. Seasonal hyperendemicity is common in the dry season between January and May13,20.
Poverty experienced by a lot of Sub-Saharan residents contributes to the severity and frequency of meningococcal meningitis [MNM]. Effective vaccines for the epidemic strains of MNM are accessible but significant proportion of the population in the belt lack the financial resources required for routine preventative vaccinations and this is the population usually affected. They depend on outside organizations such as the WHO for free or subsidized vaccinations9,11.
History has shown that the disease is importable and exportable.
Resources, infrastructure and access to primary care needed to prevent, detect and treat meningitis tends to be polarized to well-developed communities or individuals who can afford it.
High Population densities
Regarding annual incidences, population density has not been found significant but recurrences tend to occur in highly populated communities.
Immune system suppressing diseases are still significant problems in Sub-Saharan Africa. Amongst individuals, symptoms of upper respiratory tract infection were associated with asymptomatic carriage during epidemics in communities8,20. Furthermore, flu symptoms were associated with subsequent meningococcal meningitis; this relates to immune depression that results from viral infections like influenza and pneumococci. The importance of this was illustrated in 2012 by a monthly incidence of meningitis in Ghana which was associated with a simultaneous incidence of pneumonia20. Malnutrition, poverty as well as diseases like HIV serve as harbingers for immunosuppression that ravage a lot of countries in the region.
Malnutrition in children is a singular risk factor for immunosuppression which predisposes to the illness. Green foods in Burkina Faso were implicated in the disease. Green mangoes and green food laden with dust mostly consumed by children, during the hot season activated the disease in those who had predisposition20-21.
IMPACT ON THE COUNTRIES WITHIN THE MENINGITIS BELT
With over 400 million people at risk within the belt, the impact of these epidemics on the people as well as on the economy of affected countries is immense.
Families, communities, and indeed the country at large is left devastated and depleted of essential resources, further exacerbating the already pervasive poverty and preventing substantial development. On an individual level, caring for family members with meningitis is a huge financial burden. For instance, households in Ghana lose an average of 29 days of work per case and households in Burkina Faso  spend up to US$90 per case (34 percent of annual GDP per capita)2. For households struggling to make ends meet under normal circumstances, the costs are unmanageable.
In 1995, infectious diseases like meningitis contributed to approximately 42.5% of lost DALY’s. As reported by the WHO in 2002, an estimated 891 DALYs were reported to be due to meningitis, indicative of the fact that valuable productive years of the lives affected individuals are lost22. Colombini et al in a study conducted in Burkina Faso in 200822, a country at the heart of meningitis outbreaks, reported that students affected by meningitis lost 12 days of school due to the disease. The study also revealed that employed adults lost an average of 21 days of work due to meningitis. Lost days of work, reduced productivity, and the cost associated with the disease all contribute to reduced quantity and quality of the labour force and consequently minimal economic growth. These countries were therefore in a vicious, unrelenting cycle of unproductivity and lack of development. Disease results in lack of economic growth which in turn prevents development which could potentially reduce disease burden.
Control and prevention of epidemics require massive amount of vaccines, medicines, and logistic support from national health authorities of affected countries resulting in diversion of funds, material and human resources necessary for maintenance and improvement of routine health service delivery of affected countries22.
THE WAY FORWARD21
The majority of countries burdened by recurrent outbreaks of meningitis are not adequately prepared to cope with such emergencies, the need to reinforce national capacity for preparedness, detection and control of epidemic meningitis has been recognized internationally.
To respond to this challenging situation and to the expected spread of the disease, WHO, in collaboration with its member states and various governmental and non-governmental agencies, has developed a sustainable plan of action for preparedness and control of meningococcal disease in the African and Eastern Mediterranean Regions. This initiative focuses on strengthening national and regional health systems in the following key areas:
- Surveillance of communicable diseases for timely detection of outbreaks;
- Laboratory capacity for diagnosis of communicable diseases and rapid confirmation of outbreaks;
- Creation of a contingency stock of vaccine, antibiotics and injection materials and establishment of a revolving fund to ensure immediate availability of these materials in emergencies;
- Production of guidelines for the use of vaccine and protocols for appropriate case management.
While this international initiative was triggered in response to a crisis in vaccine supply for the control of severe epidemics of meningitis in Africa, it now ensures advance preparation for epidemics, with better surveillance to detect outbreaks promptly, and supplies ready for immediate dispatch to affected countries.
As part of the WHO initiative for preparedness and control of epidemics in Africa, the International Coordinating Group on Vaccine Provision for Epidemic Meningitis Control (ICG) was set up to coordinate the best use of the limited amount of vaccine available, to ensure that the meningitis vaccine was used where it was needed most and that wastage was avoided. The ICG is composed of representatives of UNICEF, the International Federation of the Red Cross and Red Crescent Societies (IFRC), Medecins Sans Frontières (MSF) and WHO, as well as technical partners from WHO Collaborating Centres and manufacturers of meningitis vaccine, antibiotics and autodestruct syringes.
The objectives of the ICG are:
- To ensure the availability and rational distribution of emergency supplies of meningococcal serogroup A and C vaccine to countries experiencing epidemic meningococcal meningitis;
- To ensure timely availability of vaccine in countries experiencing epidemics;
- To coordinate international efforts in preparing for, and responding to, epidemic meningitis.
Other WHO meningococcal meningitis programmes.
Ongoing activities include:
- Operational research to determine best strategies for deploying meningitis vaccine;
- Development of treatment, laboratory and epidemic control guidelines;
- Laboratory strengthening to ensure prompt and accurate diagnosis;
- Surveillance to gain more information on the occurrence of meningococcal disease and give a rapid alert for epidemics.
Considering the massive socioeconomic impact of meningitis epidemics over the past several decades, the importance of improved surveillance, notification, and adequate preparedness as well as improved funding and provision of vaccines cannot be overemphasized. Health education and community participation is also essential in the fight against the meningitis in sub-Saharan Africa.
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- Editorial: 100 years of epidemic meningitis in West Africa – has anything changed? Brian Greenwood Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Chalmers AJ, O’FARRELL WR. Preliminary Remarks upon Epidemic Cerebrospinal Meningitis as seen in the Anglo-Egyptian Sudan. Journal of Tropical Medicine and Hygiene. 1916;19(9).
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