MOLECULAR MARKERS IN EPIDEMIOLOGICAL MONITORING OF THE SPREAD OF RESISTANCE TO ANTIMALARIALS: A REVIEW

Abstract

Objective: 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.
Data sources: 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.
Study selection: 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.
Data extraction: From individual study or articles.
Data synthesis: 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.
Conclusion: 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.