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

• Published in: Biological rhythm research 1999-02, Vol.30 (1), p.54-81
• Main Authors: Chimanuka, B, vanden Driessche, T, Lisgarten, J N, Plaizier-Vercammen, J
• Format: Article
• Language: English
• Subjects: Plasmodium chabaudi chabaudi
• ISSN: 0929-1016
• DOI: 10.1076/brhm.30.1.54.3062

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.