Table 2.
Values used in FCM for this analysis
| Variable or Parameter | Symbol | Value | units |
|---|---|---|---|
| Background instantaneous mortality rate for mosquito age i |
rB,i |
11.75%1 |
per day |
| Length of gonotrophic cycle |
w |
2.851 |
days |
| Time spent host searching and feeding during a cycle |
b |
1.265 |
days |
| Time spent finding oviposition site and laying during a cycle |
ϕ |
1.265 |
days |
| Length of resting period (days) |
η |
0.325 |
days |
| Proportion human population infectious for malaria4 |
p |
4.28%1 |
|
| Probability attacks non-human host |
H |
0.171 |
|
| Probability killed when attacking host before biting |
a1 |
.056 |
|
| Probability killed when attacking host after biting (excluding mortality from insecticide treatments) |
a2 |
.056 |
|
| Probability becomes infected with malaria when biting infectious human host4 |
M |
1.00 |
|
| Number of eggs laid per successfully laying mosquito per cycle |
L |
1002 |
eggs |
| Time, measured in whole units equal to length of gonotrophic cycle, from infection of mosquito to cycle from which mosquito gives infectious bites |
D |
33 Based on 10.78 1 days |
cycles |
| Baseline probability that mosquito contacts and is killed by conventional instant-kill chemical insecticide (CC) whilst resting after biting human host |
k |
0for cases not assessing use of CC |
|
| |
|
0.8for cases assessing use of CC |
|
| Baseline probability that mosquito contacts and is affected by delayed action pesticide whilst resting after biting human host |
X |
0for cases not assessing use of delayed action pesticide |
|
| |
|
0.8for cases assessing use of delayed action pesticide |
|
| Number of age classes included in analysis | λ | 10 | cycles |
1.Averages taken from four geographic locations [31]. Results using individual geographic data sets are expected to give qualitatively equivalent results. Limited sensitivity analysis was consistent with this assumption, so use of the average figures was considered adequate for the present analysis.
2.Since we are only interested in comparative values, the absolute value for the number of eggs per lay is immaterial, 100 has been used as a convenient normalised value.
3.The number of cycles assumed for sporogonic development is calculated from the average number of days for sporogonic development and the average number of days per gonotrophic cycle, rounded down to give a whole number of cycles. This is a conservative assumption with respect to the amount of EIR reduction calculated for given fungal virulence parameters.
4.The data set used provides a total probability of acquiring a malaria infection when biting a human host. This has been used as the value for parameter p, with M=1.00, to give the appropriate combined probability, Mp.
5. Assumes c.11.1% of every cycle is spent resting (8 hours in a 72 hour cycle), with the rest of the gonotrophic cycle divided equally between laying and feeding.
6. Estimated 10% mortality per feeding attempt[35], divided equally between pre- and post-bite.