Antimalarial medications are the only effective way to prevent and treat malaria infection. However, some malaria parasites have become resistant to certain medications in certain areas of the world.¹ The most accurate information about malaria medication resistance in specific countries is available from the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). Three types of malaria parasites (Plasmodium falciparum, P. vivax, and P. malariae) in some areas have become resistant to some medicines.

Plasmodium (P.) falciparum resistance

The location where a person gets a malaria infection helps a doctor decide which malarial medications to use for treating the infection. For instance, P. falciparum is resistant to:

• Chloroquine in all countries with P. falciparum malaria except Central America west of the former Panama Canal Zone, Turkey, and some countries in the Caribbean.
• Chloroquine in southern China, Thailand, Myanmar (Burma), Cambodia, the Amazon River basin, the South American coast, Oceania, and in many parts of Africa.
• Mefloquine in those areas of Thailand where malaria infections occur, as well as western Cambodia and eastern Myanmar (Burma).
• Quinine in Southeast Asia, especially in the border areas of Thailand.

P. vivax resistance

P. vivax is resistant to chloroquine in Indonesia, East Timor, Papua New Guinea, and other places in Oceania.

P. malariae resistance

P. malariae is becoming resistant to chloroquinine in Indonesia.