Evaluation of Artemisia annua infusion efficacy for the treatment of malaria in Plasmodium chabaudi chabaudi infected mice

The efficacy of artemisinin (AR) against malaria has prompted its use as a tea drink in endemic communities. However, there is controversy about its efficacy in this form. Therefore we have investigated the effectiveness of Artemisia annua infusion in infected mice.OF1 mice infected with Plasmodium chabaudi chabaudi were treated for upto 6 days by administration of: water (control group), A. annua infusion (tea group), 0.022 mg AR (AR-equiv. group) and 0.8 mg AR on the first day and 0.4 mg the following day (AR-WHO group).Initially, the parasitaemia increased in all groups. On day 4 it reached 75% in the control group, 72% in the AR-equiv. group, 50% in the tea group and 3% in the AR-WHO group. Mice treated with A. annua tea died after 11 days, while 83% of AR-WHO dose survived.The tea does not decrease the parasitaemia fast enough. We suggest that large clinical trials on human subjects are necessary to ascertain the efficacy of standardized tea. Additionally, other treatment possibilities are suggested.     

Influence of the Host Photoperiodicity on the Schizogonic Cycle and the Synchronism of the Rodent Malaria Plasmodium chabaudi chabaudi

This study intended to determine whether LD (Light:Dark) regimens different from the usual 12:12 hours could impair the schizogonic cycle and the synchronism of the rodent malaria parasite Plasmodium chabaudi chabaudi. Five illumination regimens of 12:12 LD, 5:5 LD, 18:18 LD, DD (constant dark) and LL (constant light) were used. Mice were kept in these regimens three months prior to and throughout the experiment. The total and the differential parasitaemia were checked every hour, during more than 24 hours. The parasitaemia data indicated that changes in the LD regimen, except for the LD 18:18, do not affect the length of the developmental cycle of this malaria parasite which remains 24 hours. In both the LL and 18:18 LD regimens, the synchronisation of parasites were impaired, mostly in the LL regimen. Also, we noticed that the schizogony which usually occurs in the dark part of the cycle may happen in the light part too. A circadian rhythm in the frequency of the schizogonic cycle and a time dependent occurrence of ring forms, trophozoites and schizonts were observed. At high parasitaemia, the infection was desynchronised. The total parasitaemia curves displayed a plateau region, followed by a drop at the end of the plateau, and an increase after the schizogony to reach the next plateau level.     

Influence of the Host Photoperiodicity on the Schizogonic Cycle and the Synchronism of the Rodent Malaria Plasmodium chabaudi chabaudi

This study intended to determine whether LD (Light:Dark) regimens different from the usual 12:12 hours could impair the schizogonic cycle and the synchronism of the rodent malaria parasite Plasmodium chabaudi chabaudi. Five illumination regimens of 12:12 LD, 5:5 LD, 18:18 LD, DD (constant dark) and LL (constant light) were used. Mice were kept in these regimens three months prior to and throughout the experiment. The total and the differential parasitaemia were checked every hour, during more than 24 hours. The parasitaemia data indicated that changes in the LD regimen, except for the LD 18:18, do not affect the length of the developmental cycle of this malaria parasite which remains 24 hours. In both the LL and 18:18 LD regimens, the synchronisation of parasites were impaired, mostly in the LL regimen. Also, we noticed that the schizogony which usually occurs in the dark part of the cycle may happen in the light part too. A circadian rhythm in the frequency of the schizogonic cycle and a time dependent occurrence of ring forms, trophozoites and schizonts were observed. At high parasitaemia, the infection was desynchronised. The total parasitaemia curves displayed a plateau region, followed by a drop at the end of the plateau, and an increase after the schizogony to reach the next plateau level.