Nigerian authorities knew they had a major epidemic on their hands when the number of meningitis cases reported in the first two months of 1996 surpassed the total of the previous four years. The epidemic swept through at least 10 of Nigeria’s 21 states, as well as Burkina Faso and other countries in the sub-Saharan region known as the Sahel. By the time it was over in late May, the number of meningitis cases reported in Africa had reached an all-time high--more than 140,000 cases and at least 15,000 deaths. And those numbers, say officials, are most likely too low. After all, they don’t have the cdc in Nigeria, notes Marc Gastellu Etchegorry of Doctors Without Borders, an international relief organization.
The epidemic arrived with the arid season, when the air in Nigeria becomes so dry and dusty that delicate mucous membranes in the nose and throat can chap and crack. That provides a perfect entry for all sorts of respiratory bugs--including Neisseria meningitides, one of the most prevalent meningitis bacteria and the one ultimately determined to have been behind this epidemic. The bug, which often resides in respiratory tissue, becomes harmful only when it manages to penetrate through the mucosal tissue and colonize the meninges, the membranes surrounding the brain and spinal cord. Patients suffer stiff necks, intense headaches, fevers, and nausea. If their infection isn’t treated, some succumb to seizures or sepsis.
To help combat the epidemic, Doctors Without Borders and the World Health Organization sent relief workers to the hardest-hit regions. In Nigeria alone, some 30,000 patients were treated with the antibiotic chloramphenicol, and more than 3 million others were immunized. Still, it took the natural start of the rainy season in late May to put out the epidemic’s fire.
All this could have been avoided, Etchegorry notes, with a solid vaccination program. But Nigeria doesn’t have one. In this part of the world, people gain immunity to meningitis only by being exposed to the bug itself. Nigeria has had outbreaks of meningitis in the past, but they were generally small. In other words, most of the people of Nigeria--indeed, most of the people of the Sahel--had never been exposed to meningitis and thus had not developed immunity. The good news, says Etchegorry, is that they’ve now paid their dues. Now, because they have been immunized, and because they had this outbreak, they’re not at risk to have another outbreak for a number of years, he explains. But, step-by-step, the level of immunity will be reduced, and they will once again have the same risk.