## What to do

A general note: Some of the tasks below are fairly open ended. You shouldn’t go through the tasks like a check-list. Instead, explore these simulations, play with them, query them. As you do, loop through iterations of formulating your expectations for a specific scenario/task, running the model and observing results, and if results don’t agree with your expectations, figure out why. Essentially, “do science/research”.

The simulation is assumed to run in units of months, i.e. all rate parameters are assumed to be in inverse months.

### Task 1:

- Set the model parameters such that it corresponds to the following setting:
  - A population size of 1000 for both hosts and vectors, 1 initially infected host, no infected vector, simulation duration approximately 10 years.
  - Set host -> vector transmission rate, b2=0.001. Keep b1 = 0.
  - Assume that the duration of the infectious period in hosts is half a month (about 2 weeks) long.
  - Turn off births and deaths and waning immunity for now.
- Run the simulation, observe what you get.
- Now set b1 = b2, run again. Then set b1 = 2 b2, run again.
- Record the number and fraction of susceptible/infected/recovered remaining at the end of the outbreak.

### Task 2:

- Now start with no infected hosts and 1 infected vector. What do you expect to see? Run the simulation to check your expectation.
- Play around with different initial number of infected hosts and vectors and different transmission rates.
- Anything surprising happening? Do you understand why you are seeing what you see?

### Task 3:

- Turn off any infection process by setting number of initial infected hosts and vectors to 0.
- Let’s assume our vectors are mosquitos, and that they live for about 1 month. Set the death rate accordingly.
- Set the birth rate such that the vector population settles at 2000.

### Task 4:

- Turn infection process back on by having an infected host. Everything else as above.
- Contemplate the dynamics you see.
- You have births and deaths now, and usually with those you can get multiple outbreaks. Why not here?

### Task 5:

- Assume host immunity wanes after an average of 4 months.
- What do you expect to see? Run simulations to check your expectations.

### Task 6:

- Keep exploring.
- Try to figure out how the different parameters influence the dynamics, specifically the (lack of) sustained cycles.