Abstract
Mycetoma is a debilitating neglected tropical disease that ultimately destroys the bodies and lives of those it affects. It is caused by certain fungi or bacteria and classified into eumycetoma and actinomycetoma respectively. Although mycetoma is reported in many countries around the globe, information and experience on disease identification, diagnosis, and treatment are meagre. The primary disease epidemiological characteristics remain unknown, as do the true incidence, prevalence, and geographical distribution. Mycetoma is curable if discovered in its early stages. Therefore, early disease detection is the critical point in disease management that cannot be established without acknowledging the actual burden of the disease and its distribution. This thesis aimed to understand these aspects of mycetoma in Sudan using two approaches. Firstly, a community-based survey in Eastern Sennar Locality in Sennar State, Sudan, was undertaken, then historical data were compiled from the Mycetoma Research Centre (MRC) database including patients registered from all over Sudan and analysis included modelling of the distribution of the mycetoma cases and burden of mycetoma in Sudan.To address the knowledge gap in the individual and environmental risk factors, a cross sectional community-based study was conducted in sixty randomly selected villages within the five administrative units of Eastern Sennar Locality between June-July 2019. A total of 41,176 individuals were surveyed, and 359 mycetoma patients were identified. The overall prevalence was 0.87% (95%CI = 0.78-0.97%), the prevalence among males was 0.83% (95%CI = 0.71-0.96%), and females 0.92% (95% CI = 0.79-1.06%). The prevalence within individuals in the age group 31-45 years (1.52%, 95% CI = 1.23-1.86%) was the highest of all age groups. The prevalence map showed patients clustered within the central and north eastern areas, while villages in the south-western part had few or no cases.
Then, a case-control study was conducted that included the 359 confirmed mycetoma cases and three healthy individuals for each case were selected from the same villages (n=1077) with no evidence of mycetoma as a control group to address disease risk factors. An increase of one year in age is associated with a 3% decrease in the odds of contracting mycetoma (adjusted odds ratio = 0.969; 95% CI= 0.961 - 0.977). A history of local trauma (adjusted odds ratio =1.957; 95% CI= 1.478 - 2.592), unmarried status (adjusted odds ratio =3.267; 95% CI= 2.459 - 4.341) and male sex (adjusted odds ratio =1.534; 95% CI= 1.177 -1.998) all increased the risk of contracting mycetoma.
The historical data were obtained from the MRC database in Khartoum, Sudan. Demographic and clinical data from confirmed mycetoma patients seen there between 1991 and 2018. Regression and machine learning techniques were used to model the relationship between mycetoma occurrence in Sudan and environmental predictors. The strongest predictors of mycetoma occurrence were aridity, proximity to water, low soil calcium and sodium concentrations and the distribution of various species of thorny trees. The models predicted the occurrence of eumycetoma and actinomycetoma in the central and south-eastern states of Sudan and along the Nile River valley and its tributaries. Based on the estimated suitable environment and area for mycetoma occurrence, the disease burden was estimated for eumycetoma and actinomycetoma separately.
Both mycetoma types were found to have a regionally varied and different distribution in Sudan. While most eumycetoma cases were predicted to occur in the Khartoum and Al Jazirah areas, the majority of actinomycetoma cases were predicted to occur in the rural North and West Kurdufan states. In Sudan and across all states, the burden of eumycetoma is four times that of actinomycetoma. In Sudan, the risk of mycetoma is limited to certain areas, though cases are found throughout the country. This work serves as an outline for future mycetoma control and preventive endeavours, with highly endemic areas identified and resources directed to high-demand areas.
This thesis provides an evaluation of the occurrence and distribution of mycetoma in Sudan and an estimated population at risk, which provides valuable insight into the mycetoma situation in Sudan and can aid in the development of surveillance and control programs. Furthermore, risk variables at the individual level have been identified, allowing for the creation of early case diagnosis and preventive strategies.
| Date of Award | 2023 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Prof Ahmed Hassan Fahal (Supervisor) & Melanie Newport (Supervisor) |