Fig 1.
Gonotrophic cycle with vector control.
A schematic depicting the mosquito gonotrophic cycle model. In the model mosquitoes move from Blood-seeking (B), to Fed (F), to Gestating (G), to Ovipositing (O) and back to Blood-seeking. Larvicide usage impacts the emergence, or birth, rate of adult mosquitoes and LLIN and IRS interactions take place between Blood-seeking and Fed. All icons used have been made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication via Wikimedia Commons.
Fig 2.
SEI disease model in mosquitoes.
A schematic depicting the SEI (susceptible, exposed, infectious) formulation of the disease model used. Upon successful feeding, mosquitoes become infected with probability p and enter the exposed class. Mosquitoes transition from exposed to infectious at rate 1/ν, where ν is the extrinsic incubation period of malaria. All icons used have been made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication via Wikimedia Commons.
Fig 3.
Population age-distribution with disease.
Bar plots showing the age-distribution of a vector population at equilibrium (total count, indexed by number of gonotrophic cycles completed) with a variety of vector control interventions (top row) and combinations (bottom). All interventions are assumed to have 50% coverage. Bars are coloured by the proportion of vectors in each cycle generation that are susceptible (green), exposed (yellow) and infectious (red) for malaria at 40% host prevalence. Vertical lines represent the mean (dashed) and median (dot-dashed) number of gonotrophic cycles a mosquito passes through before dying.
Fig 4.
Reproductive ratio, Rc, by vector control method and coverage.
Graphs showing the relationship between Rc and coverage for the two adult-acting vector control interventions, with or without additional 50% coverage of larvicides: LLINs (solid, blue); LLINs and larvicides (dashed, yellow); IRS (dotted, red); IRS and larvicides (dot-dashed, purple). Left: linear y-axis; Right: logarithmic y-axis. All results for a mid-to-high transmission setting (R0 = 60).
Table 1.
Vector control coverage combinations required to bring Rc < 1.
Fig 5.
LLIN integrity and waning insecticidal effects.
Top row: Graphs showing the relationship between Rc (left) and vector population size (right) and LLIN coverage for good condition nets (6 holes: solid, blue; 6 holes plus 50% larvicides: dashed, yellow) and poor condition nets (80 holes: dot-dashed, blue; 80 holes plus 50% larvicides: dotted, yellow). Bottom row: Graphs showing changes in Rc and vector population size over time due to waning insecticidal efficacy with an assumed half life of 2 years, for LLINs only (solid, blue) and LLINs with 50% larvicides (dashed, yellow). All results for a mid-to-high transmission setting (R0 = 60).