Malaria is a moving target

Malaria causes the deaths of more people today than it did thirty years ago. Why? Mosquitoes and Plasmodium parasites that cause malaria have developed resistance to prevention and treatment measures.

  • Anopheles mosquitoes that carry malaria parasites have developed resistance to the pesticides used to control them.
  • The most dangerous strains of malaria, those caused by Plasmodium falciparum and Plasmodium vivax, have developed resistance to many anti-malarial drugs.
  • Parasites constantly reproduce while in their hosts and vectors—humans and mosquitoes. With each generation of parasites, genetic mutations develop that can help them become resistant to a drug’s effect.
  • Malarial parasites that are resistant to anti-malarial drugs have an advantage over other parasites. Drug-resistant parasites have a greater chance of living to infect other mosquitoes, and in turn, other people. Over time, strains of malaria that cannot be killed by current drugs spread throughout a community.

Drug resistance

Treatments exist to control malaria, but they have to change over time to combat drug resistance.

pills in a manufacturing facility
A chloroquine-containing antimalarial drug, called Musujjaquin, is producd in a factory in Uganda.

Chloroquine has been one of the most commonly used anti-malarial drugs since the 1940s. But in the 1960s, chloroquine-resistant P. falciparum parasites—which cause the most dangerous type of malaria—emerged in Southeast Asia and South America. After that, resistance rapidly spread around the world. Today chloroquine fails about two-thirds of the time.

There are reported cases of Plasmodium resistance to almost all of the first-line anti-malaria drugs.

The World Health Organization and Doctors Without Borders promote combination therapies, or treatment with two drugs at once, to combat drug-resistance. One drug kills the majority of the parasites while the other cleans up the remaining invaders.

Growing drug-resistance is one of the bigger problems in malaria control. Ineffective drugs continue to be used because they are much cheaper than the alternatives. Chloroquine costs about $0.20 a dose, while combination therapies cost about $2.40 a dose. This makes them too expensive for most people to afford in the developing countries where malaria occurs.

The Bill and Melinda Gates Foundation and Medicines for Malaria Ventures are sponsoring programs to create synthetic drugs that will sell for 1/10th the current price.

More about how parasites develop resistance to anti-malarial drugs

The Roll Back Malaria initiative reports on malaria and poverty