Seventy P. falciparum samples obtained from patients from Thai-Myanmar border were sequenced to detect mutations around the codon 268. The same samples were also sequenced to detect P. falciparum chloroquine resistance transporter mutation (PfCRT K76T).
All the 70 samples showed no mutations at the codon 268 of cytochrome b gene. Whereas, 50 samples, whose pfcrt genes were sequenced successfully, had an identical genotype for K76T mutation.
In Asian countries, even in the multi-drug resistant areas in the great Mekong region, no case of Malarone™ resistance has been reported clinically or genetically thus far. In this study, all the P. falciparum parasites tested successfully were shown to be chloroquine resistant but atovaquone susceptible genetically. The more the usefulness of Malarone™ increases for both treatment and prophylaxis, the wider the drug-resistance against Malarone™ may spread in the region. Although the total number of samples examined is not large, it is concluded from these findings that Malarone™ should be recommended for prophylaxis of malaria for travelers to the Mekong region.