Vector-borne diseases like malaria and dengue are transmitted between humans by arthropod vectors (mosquitoes).
Two-Host Model
- Humans: S → I → R (or S → I → S for dengue)
- Mosquitoes: S → I (no recovery, short lifespan)
- Transmission requires infected vector biting susceptible human
Vectorial Capacity
- V = ma²bce^(-gn)/g
- Depends on: mosquito density (m), bite rate (a), competence (b,c), lifespan (g), extrinsic incubation (n)
Control Strategies
Bednets reduce bite rate, insecticides reduce mosquito density, vaccines target human immunity.