Modelling the Transmission Dynamics of African Trypanosomiasis: A Case Study of Shimba Hills, Kenya

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Gladys Jerono Rotich

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EANBiT MSc. Fellow

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Dr. Daniel Masiga | Dr. Caleb Kibet | Dr. Leonard Kiti

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14/02/2022

Background

• African animal trypanosomiasis (AAT) is caused by Trypanosoma vivax, Trypanosoma congolense and Trypanosoma rhodesiense.

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• AAT is a life-threatening neglected tropical disease that affects livestock and wild animals.

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• Mathematical models have helped control the temporal spread of diseases.

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Background

• Tools that interrupt disease transmission exist, but their large-scale deployment is limited by high implementation costs.

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• This research aims to develop a mathematical model for factors that simulates the trypanosome vector-host transmission dynamics.

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What is a model?

A model is a simplified description of a complex entity or process.

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Why might we want a model?

• To improve our fundamental understanding of how a system works.

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• To predict or project how the system will change over time (and possibly in response to manipulation)

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Modeling Process

Problem Statement and Justification

• High bovine trypanosomiasis prevalence (33.9%) and morbidity rate (29.1%) in Shimba Hills.

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• There is no vaccine to date and the control of animal trypanosomiasis remains a major challenge.

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• Farmers are totally dependent on trypanocides to control AAT.

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• Mathematical models can been used to study the transmission and effective control of AAT.

Objectives

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Overall objective

To develop a mathematical model that simulates the trypanosome vector-host transmission dynamics in Shimba Hills, Kenya.

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Specific objectives

1. To develop a modified Susceptible-Infectious-Recovered model that simulates the trypanosome vector-host transmission dynamics.

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• To determine the basic reproduction number(R0) and document the spatial distribution of transmission risk around Shimba Hills National Reserve.

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Materials and Methods

The Susceptible-Infectious-Recovered (SIR) model

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I: the infectious (and thus, infected) animals

S: uninfected animals and tsetse sub-populations that are at risk of infection when exposed to trypanosomes

R: consists of the animals who have been treated and recovered or have died

β, the infection rate, which controls the transition between S and I

γ, the removal or recovery rate, which controls the transition between I and R

Materials and methods

Modified SIR model

Materials and Methods��

Determining the basic reproduction number(R0)

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Conceptual modeling

Data acqusition

Excel files

Mathematical modeling; generating ODE’s

Desolve package

Estimate model parameters

Python scripts

Determine R0; Maximum Likelihood

Epimodel package

Data representation

Data representation

Data representation

Data representation

Data representation

Data representation

Generating the ODE’s

Generating the ODE’s

Expected results

Acknowledgements

Supervisors

1. Dr. Daniel Masiga
2. Dr. Caleb Kibet
3. Dr. Leonard Kiti

Icipe team

1. Ken Murithi
2. Alex Kimani
3. Laurah Ondari
4. Faith Ebhodaghe
5. Stella Gachoki

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