disease gradually disappeared from Europe around the beginning of the 20th century. The United States, on the other hand, did not see malaria eradicated until a few years after World War II, in the early 1950’s. Before that time, the disease was endemic, or found locally, in several parts of the country, and especially prevalent across the southeastern states. In fact, the CDC, which originally stood for the Communicable Disease Center, was established in Atlanta, Georgia in 1946 primarily to eradicate malaria. Even today, the Anopheles mosquito is widely present in the US and on all continents except Antarctica.

So why did the disease disappear from the western world? The answer reveals the complex factors behind malaria transmission, and also suggests why the disease probably won’t stretch back topeople.

Increased animal agriculture may have helped as well. Farmers began to breed larger populations of cattle, and when humans and cattle live close together, malaria mosquitoes can be deflected to feeding on cattle rather than people, according to Reiter, the entomologist at the Pasteur Institute.

In the United States, the story was different. The CDC organized a campaign to get rid of malaria in the 1940s and 50s, which mainly involved spraying the pesticide DDT in areas with lots of malaria cases. Draining swamps and wetlands—mosquito breeding grounds—also helped in the effort. Malaria was considered eradicated from the country in 1951, according to the CDC.

These actions, along with the present day malaria medication that is available in developed countries keep malaria at bay in areas outside of the tropics.