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Mad Dogs and Chicken Heads

Modelling Disease Outbreaks and Vaccination Campaigns


Author(s)

Thomas S. Nühse
School of Biological Sciences
The University of Manchester
thomas.nuhse@manchester.ac.uk

Abstract

Although rabies still causes thousands of deaths globally every year, it has essentially been eradicated from most industrialized countries. Part of the success story is due to an unusual project undertaken by the Swiss prompted by a series of large outbreaks in the 1970s: the large-scale vaccination of wild foxes to stop the epidemic. In this directed case study, students use an easily accessible MS Excel-based model to understand key epidemiological parameters of rabies outbreaks in wild foxes. The simple model allows students also to predict what proportion of foxes needs to be vaccinated to eradicate the virus from the population. The case fits into both ecological and microbiological (epidemiological) courses and offers opportunities to explore zoonotic diseases and "One Health" questions. The mathematical basis of the differential equations in the models is explained, although prior knowledge of calculus is not essential. A key learning outcome is the critical understanding of both the power and limitations of simple epidemiological models. This case was written for an online course but could also be used as a face-to-face activity if students have access to computers in class.


Objectives

  • Define what zoonotic diseases are and explain how animal disease carriers complicate the management of epidemics.
  • Describe what the key parameters used in epidemiological modelling mean: transmission coefficient, recovery rate, latency period, basic reproductive number R0, and critical population size ST.
  • Critically discuss the simplifying assumptions, predictive power, and limitations of simple epidemiological models.
  • Interpret the patterns predicted by an epidemiological model in a biologically meaningful way.
  • Explain how an epidemiological model can guide public health policy; specifically, advise what proportion of foxes needs to be vaccinated to eradicate the rabies virus from a population.

Keywords

Epidemiology; mathematical modelling; SIR model; rabies; vaccination; zoonosis; One Health; wildlife disease; fox; foxes; transmission coefficient; recovery rate; latency period; basic reproductive number; critical population size

Topical Areas

N/A

Educational Level

Undergraduate lower division, Undergraduate upper division

Format

PDF, PowerPoint, Excel

Type / Methods

Directed, Laboratory

Language

English

Subject Headings

Biology (General)  |   Ecology  |   Epidemiology  |   Wildlife Management  |  


Date Posted

04/07/2020

Teaching Notes

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Supplemental Materials

See the case study teaching notes for details on the use of the PowerPoint presentation and two Excel workbooks below.

  
  rabies_epidemiology.pptx (~8MB)
  
  rabies_epidemiology_1.xlsx (~300KB)
  
  rabies_epidemiology_2.xlsx (~8 MB)

Answer Key

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