Table 1.
Parameters and exogenous variables – community-based, malaria parasite and human host
|
Component |
Parameter/exogenous variable |
Process-based model |
Note
%
|
||||
|---|---|---|---|---|---|---|---|
| MAC | AM | WCT | ABP | ||||
| Community-based |
Total human population at risk |
d |
d |
d |
N |
1 |
|
| Human natural birth |
|
|
|
B = δH*N |
|
||
| Human natural mortality rate |
Assuming a given average lifetime |
|
μ1 |
|
|
1 |
|
| Individual losses due to mortality or more generally, population turnover |
|
|
|
δH |
1 |
||
| Proportion of total population at risk covered with IRS program campaign |
|
|
C |
|
1 |
||
| Proportion of positive cases actually reported to health facilities |
|
|
λ |
|
1 |
||
| Malaria parasite |
Parasite species |
P. falciparum |
-- |
||||
| Sporogony/malaria parasites incubation period |
n |
n = fN/(T + l-gN) |
n = fN/(T + l*(U-υ)/U-gN) |
γP = f(T)& |
-- |
||
| Number of degree-days needed to complete parasite development |
|
fN |
fN |
|
1 |
||
| Temperature threshold below which parasite development ceases |
|
gN |
gN |
|
1 |
||
| Latency of infection in mosquito vectors |
|
tm |
|
|
2 |
||
| Human host |
Reciprocal of the average duration of the “affected state” |
r = 1/(HD + WN) |
r = 1/[HD + wn(t)] |
|
|
-- |
|
| Average time in the exposed phase |
|
|
|
1/γ |
2 |
||
| Host delay for infectivity; length of the interval between infection/sporozoite inoculation and the onset of infectivity/gametocyte maturation (HD) or latency of infection (t
h
) |
HD |
th |
|
|
2 |
||
| External force of infection |
|
|
|
βe |
2 |
||
| Probability that an infectious bite results in infection |
|
|
|
b |
1 |
||
| Host window for immunity; duration of a host’s infectivity to vectors, from the first to the final present of infective gametocytes |
WN |
wn(t) |
|
|
2 |
||
| Loss of immunity basal rate |
|
|
|
σ0 |
2 |
||
| Human recovery |
Assuming a given mean duration of infectivity |
|
|
r |
|
2 |
|
| C to S clearance rate |
|
|
|
ρ |
1 |
||
| Fraction of infections in humans that fully develops severe malaria symptoms and then receive clinical treatment |
|
|
|
ξ |
2 |
||
| Factor that decreases the per-capita transmission rate when asymptomatic but infectious individuals -I- can present a relapse of severe malaria symptoms if they are bitten again |
|
|
|
η |
2 |
||
| I to R recovery basal rate |
|
|
|
r0 |
2 |
||
| C to I recovery rate | ν | 2 | |||||
& See [36]; % 1: chosen from literature and fixed constant, and 2: chosen from literature and fitted.