Malaria, climate, and poverty

In 1995, controlling for factors such as tropical location, colonial history, and geographical isolation, countries with severe malaria had income levels only 33% of countries without malaria, whether or not the countries were in Africa. Nonetheless, the high levels of malaria in poor countries are not mainly a consequence of poverty. Malaria is very geographically specific. The ecological conditions that support the more efficient malaria mosquito vectors primarily determine the distribution and intensity of the disease. Intensive eradication efforts in the most severely affected countries have been largely ineffective. Countries that have eradicated malaria in the past half century have all been subtropical or islands. The economic growth of these countries in the 5 years following eradication has almost always been substantially higher than growth in their region. Cross-country regressions for the 1965-90 period confirm the relationship between malaria and economic growth. Taking into account initial poverty, economic policy, tropical location, and life expectancy among other factors, countries with severe malaria grew 1.3% less per person per year, and a 10% reduction in malaria was associated with 0.3% higher growth. The paper concludes with speculation about the mechanisms that could cause malaria to have such a large impact on the economy, including the possibility that the effects currently attributed to malaria are really the result of other unmeasured tropical diseases. (Author abstract)