DHFR and malaria: As atovaquone-proguanil, the proguanil component of which is an antifolate, is one of the most commonly and empirically used anti-malarials for travel-acquired malaria, it is important to understand if mutations in regions of dhfr-ts known to confer resistance in other species of malaria are present in P. ovale isolates, and if these mutations are specific to one sub-species over another.