Implements the XH component using a Susceptible-Infectious-Prophylaxis (SIP) compartmental model of malaria infection dynamics. Individuals in \(P\) are protected from infection but not from becoming infectious; they re-enter susceptibility when prophylaxis wanes.

State Variables

H

total human (or host) population density

I

density of infectious humans

P

density of humans under chemoprophylaxis

Note: susceptible density \(S = H - I - P\).

Parameters

b

transmission probability from mosquito to human

c

transmission probability from human to mosquito

r

clearance rate for infections

rho

fraction of new infections immediately treated / entering \(P\)

xi

rate of mass drug administration (\(\xi(t)\))

sigma

rate of mass screen-and-treat (\(\sigma(t)\))

eta

rate of prophylaxis waning

B

time-dependent birth rate function \(B(t, H)\)

D

linear operator (matrix) for mortality, migration, aging, and transfers

Dynamics

$$ \begin{array}{rl} dH/dt &= B(t,H) + D \cdot H \\ dI/dt &= (1-\rho)hS - (r + \xi + \sigma)I + D \cdot I \\ dP/dt &= \rho hS + \xi(S+I) + \sigma I - \eta P + D \cdot P \\ \end{array}$$ where \(h\) is the force of infection and \(S = H - I - P\).