Date of Award


Degree Name

Doctor of Philosophy (College of Medicine)

Schools and Centres


First Supervisor

Doctor Edward K. Waters

Second Supervisor

Professor Harvinder Sidhu


Gashoho Health District, Burundi, has not achieved the World Health Organisation (WHO) target of elimination of the blinding infectious disease, trachoma, by 2020. The work in this thesis addresses this problem using three different approaches.

Firstly, a cross-sectional study was undertaken to establish the current trachoma prevalence in Gashoho and whether poor sanitation was a risk factor for infection. 468 individuals from 117 households across four villages were clinically examined for signs of trachoma infection, and completed a questionnaire about environmental risk factors. The current prevalence of trachoma in Gashoho was 7.9% (95 % CI 5.0 - 10.6%). Children under 9 years old had an overall prevalence of 19.5% (95% CI 13.7-26.4%). Household access to a sanitary toilet almost halved the odds of trachoma infection (OR 0.437, 95 % CI 0.256 - 0.743).

Then, mathematical models based on the SIS framework, but incorporating environmentally mediated transmission, were utilised to explore whether improved sanitation might eliminate trachoma in Gashoho. Stability analysis showed the existence of two basic reproductive numbers, R0H and R0E, governing human-to-human and environmentally mediated transmission. Persistence of trachoma was shown to depend on the sum of these quantities exceeding one. Numerical simulations suggested that the elimination of trachoma was possible in Gashoho, given environmental interventions that increased pathogen clearance from the environment.

To complete the work in the thesis and allow rapid translation of the results into policy and practice, a new method of monitoring and evaluation of environmental interventions was proposed. Using computational and algebraic methods, Stratified Truncated Sequential Sampling was developed to link monitoring in individual villages to policy decisions at the Health District level.

In conclusion, this thesis generates new knowledge and methods for improving trachoma control efforts in Gashoho Health District, Burundi.

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