16.6 Treatment and Chemoprotection
It is impossible to understand malaria infection dynamics without accounting for treatment with anti-malarial drugs and a brief period of chemo-protection that follows. The first model for drug treatment was developed to understand MDA [77]. In developing models for policy, we must be careful about drug taking and its effects because it modifies the relationship between exposure (the EIR) and infection.
16.6.1 The Time Course of an Infection
The time course of infections is complex, and we will need to develop some models that relate parasite densities. In the chapters that follow, we introduce two main kinds of models:
AoI
SoI
16.6.2 Intrahost Models
There are two kinds of models we will discuss, but we would like to avoid them in making policy if possible.
In host models;
Individual-based models.
16.6.3 Synthesis
In the end, we do not need perfect models of malaria infection and immunity, but we do need a sound understanding of several things to make policy:
The prevalence of infection by age as a function of exposure and drug-taking;
…in a cross-section of the population;
…in the care-seeking population.
The incidence of malaria by severity and by age;
The fraction of malaria that is promptly treated by severity and by age;
The net infectiousness of a population of humans to mosquitoes.
In the chapters that follow, we will develop some models that based on a new concept – the age of the youngest infection – that combine many of the ideas in the chapters above.