Modelling the dynamics of asexual Plasmodium falciparum parasites in the blood and their interaction with the human immune system
To describe the parasitaemia of people who experience a Plasmodium falciparum infection for the first time, a semi-stochastic difference equation was developed. The parameters were estimated from historical data of syphilitic patients who had undergone a malario-therapy and from whom daily blood samples had been obtained. The results of our model were compared to "targed statistics" for biologically relevant aspects (calculated from the data of syphilitic patients).
The model output was more realistic than any previously published model result. Its highly realistic behaviour was achieved by a combination of
- intra-clonal antigenic variation
- large variations of the variants' baseline growth rate, depending on both variant and case
- innate autoregulation of the asexual parasite density, variable among cases
- acquired variant-specific immunity
- acquired variant-transcending immunity, variable among cases