The Epidemiology of Acute Gastrointestinal Illness in Ethiopia, Mozambique, Nigeria, and Tanzania

Abstract

Gastrointestinal infections transmitted by food are a global concern and most severe in African low-and-middle-income countries (LMICs), though in these countries accurate data on acute gastrointestinal illness (AGI) are lacking. The thesis aimed to estimate the epidemiology of AGI in Ethiopia, Mozambique, Nigeria, and Tanzania; because this research was interrupted by the COVID-19 pandemic, a secondary aim was to explore application of methods typically used to adjust for under-reporting of foodborne infections to COVID-19. The thesis objectives were to: describe the epidemiology of AGI at the population level in Ethiopia, Mozambique, Nigeria, and Tanzania; evaluate the multi-national collaborative process used to achieve the first objective; and apply methods used for foodborne infections to estimate the under-ascertainment multipliers for each step in the reporting chain for COVID-19 for an example setting with available data (Toronto, Canada). To determine the epidemiology of AGI, a population survey was conducted in one urban and one rural site in each of Ethiopia, Mozambique, Nigeria, and Tanzania, from October 01, 2020 to September 30, 2021, using both web-based and face-to-face survey tools (n=4487). The incidence of AGI (0.5 episodes per person-year) was comparable or lower to other LMICs, the duration (4 days) appeared slightly longer or comparable to other LMICs, and although age was a significant risk factor, gender was not. The multi-national collaboration that supported this population survey was evaluated using Larkan et al.’s (2016) framework and its seven core concepts: focus, values, equity, benefit, communication, leadership, and resolution. The evaluation identified that the partnership considered the interplay and balance between operations and relations, and featured a shared goal, mutual benefits, transparency, inclusiveness, and leadership attributes. A slight working culture difference was noted, with a need to enhance responsibility-sharing and dedication. Finally, application of foodborne underreporting adjustment methods to COVID-19 was done for Toronto, Canada, where all necessary data sources (de-identified reported case data, weekly testing data, and population survey data) were available. Specifically, stochastic modelling was applied to estimate the under-ascertainment rate of COVID-19 in Toronto at early stages from March 2020 (the beginning of the pandemic) through May 23, 2020. Overall, 1 in 18 COVID-19 infections that occurred in the community were reported to Toronto Public Health. The under-ascertainment approach yielded comparable estimates to seroprevalence studies, and this approach allowed identification of where cases were lost in the reporting chain. In conclusion, this thesis identified that in Ethiopia, Mozambique, Nigeria, and Tanzania, AGI appears to pose a considerable incidence that suggests regular surveillance and intervention are needed. Future population surveys or other collaborative burden of infectious disease studies in African or other LMICs may benefit from partnerships that consider the interplay and balance between operations and relations and leadership attributes (and their dependent resolution strategies) such as the full and equitable delegation of tasks that eliminated hierarchical positionality and the flexibility to altering some premade decisions and executing action points. Finally, the COVID-19 pandemic provided an opportunity to apply the under-ascertainment measurement approach used for foodborne infections and influenza to COVID-19, and this thesis demonstrated that the under-ascertainment method typically applied to foodborne infections is useful for other infectious diseases under public health surveillance.