Drug resistance in malaria

Area of Science:

• Medical Entomology
• Molecular Biology
• Epidemiology

Background:

• Southeast Asia emerged as a critical region for Plasmodium falciparum drug resistance with the discovery of chloroquine resistance in the late 1950s.
• The emergence of resistance led to the sequential replacement of antimalarial drugs, including chloroquine, sulphadoxine-pyrimethamine (SP), and mefloquine, with artemisinin-based combination therapies by the mid-1990s.
• Alternative treatments for chloroquine-resistant malaria are often more expensive, have greater side effects, and are harder to comply with than chloroquine.

Purpose of the Study:

• To review the current knowledge on drug-resistant malaria.
• To outline the changing patterns of drug resistance, its determinants, and geographical distribution.
• To discuss molecular markers and their implications for controlling drug-resistant malaria.

Main Methods:

• Review of historical data on antimalarial drug resistance.
• Analysis of geographical trends in drug resistance.
• Identification and discussion of molecular markers associated with resistance.
• Evaluation of epidemiological tools for monitoring drug resistance.

Main Results:

• Chloroquine resistance in Plasmodium falciparum originated in Southeast Asia and spread globally.
• Multiple drug resistance has necessitated the adoption of artemisinin-based combination therapies.
• Molecular markers such as pfmdr-1, pfcrt, dhfr, and dhps polymorphisms are associated with resistance to various antimalarials.
• Genetic information can aid in early detection and monitoring of drug resistance foci.

Conclusions:

• Urgent development of effective, affordable alternative antimalarial regimens is crucial.
• Molecular markers are valuable epidemiological tools for monitoring and controlling drug-resistant malaria.
• Integrated strategies combining molecular surveillance with conventional assessments are needed to limit the spread of drug resistance.