[First major epidemic caused by Neisseria meningitidis serogroup W135 in Africa?].

Neisseria meningitidis serogroup W 135 (N.m. W 135) has caused sporadic infections and small epidemics such as those that occurred during religious pilgrimages in Saudi Arabia in 2000 and in 2001. It is routinely isolated from specimens coming from African countries. The first major epidemic involving N.m. W 135 occurred in Burkina Faso between January and May 1992. There were more than 1300 cases including 1500 deaths. Enhanced surveillance of circulating strains showed that N.m. W 135 accounted for 83% of the 203 positive cerebrospinal fluid specimen cultures. The offending organism was identical to the strain that caused the smaller epidemic in Saudi Arabia in 2000. Due to the shortage of tetravalent meningococcal vaccine against N.m. W 135, the Health Ministry based its response to the epidemic on treatment of symptomatic patients using chloramphenicol and ampicillian. These drugs were distributed free. The emergence of N.m. W135 has impacted public health in Africa. Repeated identification of this serogroup in Burkina Faso during 2002 raises the risk that similar outbreak will occur in the meningitis belt during the next epidemic season. The high cost of tetravalent meningococcal vaccine compounded with the only progressive increase in production capacity underline the need to reinforce surveillance of circulating strains and available treatment facilities. Control strategy for epidemic meningitis is currently the focus of close collaboration between the WHO and the health authorities and corresponding institutions in the countries involved.