15,595 meningitis cases this season in Africa

Mar 19 2007

Two months into the dry season in the African "Meningitis Belt", 15,595 cases including 1,670 deaths have been reported to the World Health Organization (WHO) from four countries: Burkina Faso, the Democratic Republic of the Congo, Sudan and Uganda.

Two of these countries, Uganda and the Democratic Republic of the Congo, are at the extreme south of the "Meningitis Belt," which stretches from Senegal in the West to Ethiopia in the East, an area with an estimated population of 300 million people. The samples taken show that these cases are caused by Neisseria meningitidis serogroup A, the most common serogroup in Africa.

In northern Uganda, 2961 cases including 105 deaths have been reported in several areas. A campaign of vaccination has been completed in some areas and is continuing in others. WHO and Médecins sans Frontières (MSF) are working together to contain the outbreak. In southern Sudan, 6946 cases including 430 deaths have been reported from nine out of ten states. In Burkina Faso 4958 cases including 432 deaths were reported. In the Democratic Republic of the Congo, 730 cases and 84 deaths have been reported.

The International Coordinating Group (ICG)* on Vaccine Provision for Epidemic Meningitis has so far released 1.1 million doses of vaccine to respond to the outbreak in southern Sudan and is ready to provide additional doses if needed. Around 1.5 million people in affected counties have been targeted in mass vaccination campaign organized by the National authorities, WHO, MSF, International Medical Services, as well as other NGOs present in the area, and supported by UNICEF, OCHA, the European Community Humanitarian Office (ECHO). The affected areas are known to host large numbers of returnees, as well as displaced populations living in areas not easily accessible and dispersed population settlements.

Vaccination campaigns are on going in Burkina Faso, where the ICG has already released 530 000 doses. WHO is present in the field in all the affected countries, assisting with the surveillance and control measures. The WHO and partners have provided drugs for case management as well as emergency supplies for outbreak investigation and technical guidance for outbreak control and management.

In the African Meningitis Belt, enhanced epidemiological surveillance and prompt case management with oily chloramphenicol - the standardized antibiotic treatment - are used to control epidemics. At the same time, WHO and partners recommend reactive mass vaccinations targeted at the highest risk groups, usually people between the ages of 2-30 years. Every district that is in an epidemic phase, as well as adjoining districts that are in the alert phase, should be targeted for vaccination It is estimated that a mass immunization campaign, promptly implemented, can prevent 70% of cases.

This season, the ICG secured some 8 million doses as an emergency stockpile. 5.5 million doses are currently available. Despite concerns about a shortage of vaccine, WHO estimates that some 15 million doses are still available on the market, which countries can purchase. Furthermore, to rapidly address the potential shortage of vaccine supply, WHO decided to assess the status and production capacity of polysaccharide manufactures worldwide. One manufacturer, Bio-Manguinhos in Brazil, was identified as the strongest and quickest alternative for scaling-up vaccine supply in the short and medium term. In partnership with the Finlay Institute in Cuba, Bio-Manguinhos is working with WHO to ensure a supply of up to 10 million doses of bivalent AC meningitis vaccine by the next epidemic season .

Meningitis is an infection of the meninges, the thin lining that surrounds the brain and the spinal cord. Several different bacteria can cause meningitis. Neisseria meningitidis is one of the most important because of its potential to cause large epidemics. Meningococcal disease was first described in 1805 when an outbreak swept through Geneva, Switzerland.

The bacteria are transmitted from person to person through droplets of respiratory or throat secretions. Close and prolonged contact (e.g. kissing, sneezing and coughing on someone, living in close quarters or dormitories (military recruits, students), sharing eating or drinking utensils, etc.) facilitate the spread of the disease. The average incubation period is 4 days, ranging between 2 and 10 days. N. meningitidis only infects humans; there is no animal reservoir.

The most common symptoms are stiff neck, high fever, sensitivity to light, confusion, headaches and vomiting. Even when the disease is diagnosed early and adequate therapy instituted, 5% to 10% of patients die, typically within 24-48 hours of onset of symptoms. Meningococcal disease is potentially fatal and should be viewed as a medical emergency. A range of antibiotics may be used for treatment.

The highest burden of meningococcal disease occurs in sub-Saharan Africa, which is known as the “Meningitis Belt”. This hyperendemic area is characterized by particular climate and social habits. During the dry season, between December and June, because of dust winds and upper respiratory tract infections due to cold nights. The transmission of N. meningitidis is facilitated by overcrowded housing at family level and by large population displacements due to pilgrimages and traditional markets at regional level.

WHO promotes a two-pronged strategy which involves epidemic preparedness and epidemic response. Preparedness focuses on surveillance, from case detection and investigation and laboratory confirmation. Epidemic response entails a prompt and appropriate case management as well as timely reactive mass vaccination.

An improved and affordable conjugate vaccine is expected by 2010. It will offer longer lasting protection, allowing preventive immunization. WHO supports the development of such a vaccine through the Meningitis Vaccine Project (partnership between Program for Appropriate Technology in Health -PATH and WHO).