Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 31. (Budapest, 1998)

Male Swiss outbred mice (Iffa Credo, France) were used to the follow up the infection and 4 batches of 5 mice each were inoculated intraperitoneally with merozoites of 4 above-mentioned Plasmodium species, according to Montalvo-Alvarez et al. (1988). The parasitic pattern can be expressed as the relative proportion of each stage: rings, young trophozoites, mid-term trophozoites and old trophozoites according to the classification by Cambie et al. (1991 ). The evolution of the parasitic pattern was followed when parasitaemia reached 1% or more. Blood 0 6 12 18 24 30 36 42 48 100 P. b»rghml P. y. killicki 0 6 12 18 24 30 36 42 46 -I

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—r— 6 12 18 24 30 36 42 48 Fig 1. Follow-up of the mean percentages of mid-term trophozoites (MTs) of 4 batches of mice (n = 5) infected with/? c. adami, P. v. vinckei, P. berghei and P. y. killicki evaluated at 6-hour intervals over 42-48 hours. smears were performed at 6-hour intervals during 42 to 48 hours and all experiments were stopped before the parasitic crisis. The evolution of the percentage of mid-term trophozoites (MT) is plotted on Figure 1. Clearly, P. c. adami and P. v. vinckei (P. v. vincke data from Gautret et al. 1994) developed synchronously showing, well-marked peaks of MTs at 24-hour intervals. In contrast, P. berghei and P. y killicki did not show any peak of MTs due to their asynchronous development. Rings, young trophozoites and old trophozoites followed the same general pattern (data not shown). Results were then processed to calculate the synchronicity index (SI) from the standard deviation of the parasitic pattern at a given time using the following formula: T~ _ x = relative percentage of each type of asexual stage at a given X(

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~* ) time and 50 being the standard deviation in a 100 % synchroä K • 4 nous infection 50 The SI varies between 0 (total asynchronicity) and 1 (total synchronicity)