A strain of monkey malaria (Plasmodium cynomolgi) made resistant to proguanil (paludrine)

Abstract
Subeffective treatment of infections of monkeys by proguanil has produced strains with 1000 times the resistance to the drug present in the original strain. Such resistance is not impaired by passage through mosquitoes nor does freezing of infected blood change the reaction. Pre-erythro-cytic, endo-erythrocytic, and gametocytic stages all show this increased resistance. Such strains are readily controlled through sulphadiazine therapy.