Climate and Meningitis in Africa
We hear a lot about the impact of AIDS, tuberculosis and malaria in Africa. But if you’re keeping track, you may as well add bacterial meningitis to the list of nasty diseases that plague the continent.
Bacterial meningitis is an infection of the thin lining that surrounds the brain and the spinal cord, known as the meninges. The most common symptoms are stiff neck, high fever, headaches, and vomiting – but even when the disease is treated early, 5-10 percent of patients die within 48 hours. Those who survive often suffer long-term side effects including brain damage and hearing loss.
While meningitis occurs all over the world, the highest disease burden is found in sub-Saharan Africa, in an area that stretches from the Gambia to Ethiopia, known as the Meningitis Belt. The disease is quite common throughout the area from February to May, but some years are worse than others: major epidemics striking up to 200,000 people have occurred in cycles of 8-12 years. In recent years, however, the epidemics seem to be occurring more frequently.
Though a number of factors (crowding, population displacement, herd immunity, etc.) influence the year-to-year prevalence of meningitis in Africa, the seasonality of the disease connects infection and climate in a way that can’t be denied. For instance, meningitis outbreaks only occur during the dry season, when temperatures fall at night and people huddle together for warmth. This is also the time in which the dry, dust-laden Harmattan winds blow from the north, damaging the mucous membranes of the respiratory system.
But while this much is understood, great deal more is still a mystery. Indeed, while the connections between climate and health can’t be denied, neither can they be entirely understood — at least not yet.
In pursuit of a more perfect understanding, researchers working to unravel the connections between climate and meningitis got together last week at the Mailman School of Public Health. The conference, called Epidemics and the Environment: The Meningitis Challenge in Africa, was presented in conjunction with the Center for International Earth Science Information Network and the International Research Institute for Climate and Society (IRI). It was opened by Mailman’s dean, Dr. Linda Fried, and chaired by Dr. Patrick Kinney, director of the Columbia Climate and Health Program. The conference was also incorporated into the IRI’s Summer Institute on Climate Information for Public Health.
Conference talks covered a range of issues. Dr. Tom Clark of Centers for DiseaseControl and Prevention introduced the Meningitis Vaccine Project, a partnership between the World Health Organization (WHO) and the Program for Appropriate Technology in Health that works to eliminate epidemic meningitis as a public health problem in Sub-Saharan Africa.
Dr. Eric Bertherat of the WHO outlined the efforts made by the Meningitis Environmental Risk Information Technologies Project to use existing knowledge to improve the understanding of the relationship between bacterial meningitis and environmental parameters. He also explored the potential to use this understanding to provide more timely warnings of the onset of meningitis epidemics and improve the efficacy of prevention and control.
This topic was later picked up by Dr. Madeleine Thomson of the IRI, who discussed ways that climate information might be able to improve meningitis control.
Dr. Patrick Kinney of Mailman, Dr. Sylwia Trzaska of the IRI and Dr. Yonas Asfaw from Ethiopia’s Federal Ministry of Health also joined in on the discussion. This group brought up possible mechanisms to illuminate the seasonality of carriage, rather than infection, and the potential benefits of further illuminating the relationship between climate and disease prevalence.
In the end, the conference served to raise as many questions as it answered, but it also served to underscore the need for climate and health experts to team up to combat meningitis in Africa – particularly since creeping desertification and dust storms may increase prevalence as our climate changes. It also served to highlight the fact that a way of predicting these meningitis epidemics would be enormously useful.