[A handy medium for in vitro assessment of sensitivity of Plasmodium falciparum to chloroquine and mefloquine in the field].

The use of liquid RPMI 1640 medium (added NaHCO3 and serum) in sealed ampoule for in vitro assessment of sensitivity of Plasmodium falciparum to chloroquine and meflopuine in the field was very successful. On chloroquine plates with WHO supplied medium, 9 of 13 isolates were interpretable (successful rate 69.2%), the maturation rate from ring-forms to schizonts was 53.3%, the average number of nuclei per schizont 5.1. With lyophilized medium the successful rate was 100%, the maturation rate 65.9%, the average number of nuclei per schizont 7.4, while with medium in sealed ampoule, the corresponding figures were 92.3%, 65.1% and 7.3 respectively. On mefloquine plates with WHO supplied medium, 7 of 11 isolates were interpretable (63.6%). In control wells, 52.3% of schizonts matured, the number of nuclei per schizont was 5.1. With lyophilized medium the successful rate was 100%, the maturation rate 61.9%, the number of nuclei was 8.1, while those with liquid medium in sealed ampoule were 100%, 59.8% and 7.5 respectively. The results showed that the liquid medium in sealed ampoules stored within 56 days at 4 degrees C could still support the growth of Plasmodium falciparum, its supporting effect being better than that of WHO standard medium, but similar to lyophilized medium. The liquid medium in sealed ampoule had the advantages of easy carrying time-saving and more applicability under field conditions.