What is malaria?

It kills hundreds of thousands every year—but those numbers are falling fast.

Malaria is a potentially fatal disease spread to humans by infected mosquitoes. It occurs mostly in sub-Saharan Africa and Southeast Asia. In 2012, there were an estimated 207 million cases of malaria (about 1,500 are diagnosed in the United States each year), of which about 600,000 resulted in death.

What are symptoms of malaria?

Within 10 to 15 days of being bitten, a victim can exhibit symptoms including fever, headache, and vomiting. Those are a result of microscopic parasites multiplying in the victim’s liver, disrupting blood supply to vital organs. Left untreated, the process can result in death.

How is malaria spread?

Mosquitoes carrying the Plasmodium parasite that causes malaria usually bite at night in hot, humid regions, especially in sub-Saharan Africa and Southeast Asia after rainy seasons. Children are especially vulnerable to malaria. It does not spread from human to human.

How do you prevent malaria?

More than 3 billion people—half the world’s population—are at risk of contracting the disease, according to the World Health Organization. The good news? Malaria is both preventable and curable. Thanks to a surge in funding for programs targeting the disease, malaria mortality rates have fallen by almost half since 2000. This map gives you an idea of which countries are doing the best job of beating it down.

To keep the bugs at bay, people may drape their sleeping areas with insecticide-treated nets or spray insecticide in and around the premises. Travelers from non-affected countries are usually advised to take anti-malarial pills before arriving in those risk areas.

Malaria is transmitted to humans by infected mosquitoes. (Photo: Haykirdi/Getty Images)

Researchers in several countries are also working on projects to genetically modify mosquitoes to keep them from spreading malaria. The latter is crucial, because growing numbers of Plasmodium types have developed resistance to many medicines.

More controversially, the pesticide DDT, which was famously banned in the U.S. and most other countries because of concerns about its impact on the environment and human health, is still used in some places to fight malaria. South Africa credits it with cutting its malaria deaths from 460 in 2000 to 70 in 2012.

Is there a vaccine for malaria?

Scientists have been working on a vaccine for decades. In mid-2014, researchers at GlaxoSmithKline came up with one that looks promising. It may be approved for use as soon as 2015.

What is the treatment for malaria?

Treatment varies, depending on the type of malaria, where it was acquired, and the victim's health status. Once those things are determined, the parasite can be attacked with a range of drugs. Most are based on artemisinin, a substance extracted from the sweet wormwood tree. Many strains of malaria are becoming resistant to various types of artemisinin-based medicines.

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