Introduction

The model uses real life data from the Ebola outbreak in Kikwit

You are provided with access to online software to run the model. This will produce all the relevant tables and figures. You are not expected to derive any equations nor to analyse numerical output mathematically. Figures can be copied directly from the interface. There is no need to reference the software itself. Just use the model to experiment and try out your ideas.

The link to run the model is here.

http://r.bournemouth.ac.uk:3838/Epidemics/Ebola/

How to run the model

The model interface on the left hand side has a tab with sliders to set model parameters.The data for the model is taken from the published literature.

Your assignment will involve two activities:

Research

Reading: Research the key characteristics of Ebola in order to understand the nature of the disease, its form of transmission, and the means through which epidemiological modelling can guide measures taken to control an outbreak. Find peer reviewed academic references from the web of science and other sources that help deepen your knowledge of the disease. Include this information in both the introduction and the discussion section. Fully reference all your sources including any additional non peer reviewed pre-prints and reports from public health bodies if used.

Modelling

Modelling: Based on your research into the background suggest three different sets of control measures aimed at altering key parameters of the model. Your interventions may be aimed at mitigating the impact of the disease and/or controlling it completely. The ability of health infrastructure to treat patients should be considered. Wider considerations of the impact of measures should also be taken into account. You should be aware that control of Ebola differs in many respects from control of a respiratory virus and that many of the measures would be adopted within the hospital where the outbreak was concentrated. Do not draw too directly on the experiences of the covid pandemic with respect to societal wide measures, as there are many differences. Some interventions may lead to unintended negative effects, such as increasing the duration of the outbreak or leaving sections of the population at risk vulnerable to subsequent outbreaks. Use the model interface to assess the likely effect of your proposed measures.

Example of a measure that may change a range of parameters.

You might propose to bring in more nurses to treat patients. This would seem to be a good intervention that could save lives. However the intervention will affect almost all the potential parameters depending upon how the intervention is managed and whether additional measures are also used.

  1. The population at risk will increase.
  2. Contacts between people may also increase.
  3. Treatment of the ill may improve, lowering the risk of death.
  4. Nurses may diagnose patients earlier leading to more effective isolation of the sick

So, for the purposes of the assignment you should make minor modifications to the model that reflect the sort of changes that might occur. Do not try to be too precise. It is impossible to quantify the effects with any certainty, and that is not the objective of the exercise. Use the model as a guide to the sort of impact that might occur and as a way of thinking in a structured manner about additional measures that may be needed.

Marking criteria

Criteria 1: Introduction and aims (30%) approximately 500 words

A concise summary of the background to your study in the style of a published paper. Two sub criteria will be used in marking. 1. Style and clarity of expression 2. Content: Summarise the key characteristics of the disease and potential control measures.

Criteria 2: Methods (20%) approximately 300 words.

Clearly explain the characteristics of the models you used. Explain how your proposed interventions can be captured by alterations to the key parameters of the SIR model. Two sub-criteria will be used when marking of this section.

  1. Clarity and brevity of expression.
  2. Evidence of understanding the underlying concepts used when structuring and parameterising the model and the way the impact of interventions influence model parameters.

Criteria 3: Results and discussion (50%) approximately 1200 words

Explain to the reader what the model output actually implies and how the interventions have changed the dynamics of the outbreak. Some interventions may alter overall mortality or morbidity without changing the time span of the outbreak. Others may alter the overall pattern in unexpected ways.

Include figures and summary statistics to illustrate these outcomes clearly. A single figure may involve a set of sub-figures illustrating a range of outcomes. Use detailed figure captions to ensure that the contrasts are clearly pointed out to the reader. Critically discuss your finding and place them in the context of published literature.

Six sub-criteria will be used when marking this section

  1. Clarity of the presentation and explanation of the results
  2. Evidence of an understanding of the underlying model
  3. Awareness of the key assumptions used in modelling
  4. Critical appraisal of the ability of SIR models to produce quantitative predictions.
  5. Critical discussion of the practical implications of proposed interventions.
  6. Use of original scientific literature to place your results in the context of developing knowledge with regards to the control of Ebola.

Reference

The data are taken from

A.S. Khan, et al. 1999. The reemergence of Ebola hemorrhagic fever, Democratic Republic of the Congo, 1995. J Infect Dis 179:S76-S86.