Model Overview

This interactive model simulates Rocky Mountain spotted fever and the brown dog tick (Rhipicephalus sanguineus) dynamics to explore how control strategies affect tick populations and infection prevalence over time.

You can adjust the parameters to explore how different population sizes, environmental conditions, and management strategies influence tick and disease dynamics. Default values represent baseline scenarios.

Adjustable Parameters

Population Parameters

Parameter	Description
Tick Population	Total number of ticks at the start of the simulation.
Proportion of Ticks Infected	Initial proportion of ticks carrying the pathogen.
Proportion of Dogs Susceptible	Initial proportion of uninfected dogs in the population. The proportions of susceptible, infected, and recovered dogs always sum to 1. Changing the proportions in one compartment will automatically adjust the others to maintain this total. This value autopopulates based on the values chosen for proportion infected and recovered.
Proportion of Dogs Infected	Initial proportion of infected dogs. Infected dogs may transmit disease until they recover or die. They may move to the recovered compartment after an average of 7 days.
Proportion of Dogs Recovered	Initial proportion of recovered dogs. Recovered dogs may lose immunity and return to the susceptible compartment after an average of 6 months.
Proportion of Dogs that are Inside-only	Initial proportion of dogs that live in a home. The proportions of indoor, roaming, and stray dogs always sum to 1. Changing the proportions in one compartment will automatically adjust the others to maintain this total. This value autopopulates based on the values chosen for proportion roaming and stray
Proportion of Dogs that are Stray	Initial proportion of dogs that are unowned and live outdoors.
Proportion of Dogs that Roam	Initial proportion of dogs that can move between homes and outdoors.

Simulation Parameters

Parameter	Description
Number of Simulations	Number of times the model will be run.
Number of Years	Length of each model run.
Climate Type	Determines whether tick populations experience winter diapause (Temperate) or remain active longer throughout the year (Tropical).

Treatment Parameters

We suggest waiting until the 2nd year to start treatment, allowing the population time to stabilize.

Parameter	Description
Dog Acaricide	Controls the timing, coverage, and type of acaricide treatment for dogs. The duration is assumed to be the following: Bath = 7 days, Oral = 1 month, Collar = 6 months. The efficacy is assumed to be the following: Bath = 50%, Oral = 90%, Collar = 90%.
Environmental Acaricide	Controls tick reduction in the environment.
Dog Removal	Controls dog culling. Dog removal occurs once per round.
Spay/Neuter	Controls reproductive management of dogs. Spay/neuter is applied once per round.