The discovery could make it possible to bring back the drug chloroquine or develop new medications.
Malaria is caused by a parasite carried by the mosquito.
After 15 years of work, researchers have pinpointed the changes in the DNA of the malaria parasite that lead to chloroquine resistance. Chloroquine has been used to combat malaria since the 1940s. It is cheap and effective. But in recent years the malaria parasite has become resistant to the drug, and it can no longer be used in many countries. Now scientists believe they have discovered how the parasite evades man's efforts to control it with chloroquine.