Molecular markers in epidemiological monitoring of the spread of resistance to antimalarials: a review.

Abstract

To review the prevalence and distribution of resistance to chloroquine and pyrimethamine-sulphadoxine combination and the use of molecular markers for monitoring the spread of the resistance. Literature search on compact disk-read only memory (CD-ROM), Medline and Internet, using the key words: Malaria and epidemiology, malaria and resistance, sulphadoxine-pyrimethamine resistance and chloroquine resistance. Some articles were manually reviewed. Relevant studies or articles on resistance to chloroquine, sulphadoxine pyrimethamine combination and other antimalarials and molecular resistance markers from various sources are included in the review. From individual study or articles. Information on antimalarial resistance is harmonised under the headings; Introduction, Prevalence and distribution of resistance to antimalarials, Use of molecular markers for epidemiological monitoring of antimalarial resistance. The spread and status of resistance to sulphadoxine-pyrimethamine (SP) and chloroquine should be monitored constantly in major health facilities. This will not only detect the emergence of resistance to these drugs but also generate information on the extent of resistance to these antimalarials. Mutations in the dhfr and dhps genes can be used as markers in SP resistance surveilance while the presence of pfcrt mutations thought to confer resistance should also be analysed to ascertain whether they truly correlate to the resistance patterns that have been observed in various malarious regions. Little is known on the interaction and exact role(s) of PfCRT protein in conferring the resistance trait.