An analysis of multimorbidities associated with schistosomiasis infections in sub-Saharan Africa
An estimated 250 million people worldwide have schistosomiasis infections, of which 80% are in sub-Saharan Africa. In 2017, schistosomiasis caused at least 1.43 million disability-adjusted life years lost. Blood flukes (parasitic worms) cause schistosomiasis. It is a chronic infection where individuals are affected over their life course. If left untreated, the various species of schistosomes can cause bladder cancer, liver fibrosis, diarrhoea, gastrointestinal haemorrhage, anaemia, malnutrition, and portal hypertension as well as long-term impairments such as reduced cognitive development, educational attainment, and work productivity. The only treatment strategy for schistosomiasis is mass drug administration with praziquantel. Yet, repeated mass drug administration neither resolves schistosomiasis-associated morbidities nor prevents reinfections.
World Health Organization guidelines suggest that schistosomiasis-associated morbidities are concentrated among individuals with severe/heavy infections. Yet, due to the long lifespan of the parasite, it is possible to detect morbidity without detecting infections. This is due to several reasons, including 1) morbidity developing early in life and remaining throughout adulthood, 2) the impact of repeated treatment, 3) poor diagnostics, and 4) the complex aetiologies of schistosomiasis-associated morbidities. Additionally, a major neglected issue is the presence of multimorbidities, i.e. two or more chronic conditions. Morbidities are often studied in isolation for schistosomiasis as opposed to identifying conditions that interact, have similar aetiologies, or share treatment strategies.
RESEARCH EXPERIENCE, RESEARCH METHODS AND TRAINING
This project will use data from ongoing studies in rural villages in Uganda where Schistosoma mansoni (intestinal schistosomiasis) is endemic. Ethics approval will be obtained prior to the start of this project. Depending on restrictions due to the ongoing pandemic, it is expected that this data will be collected prior to the start of this DPhil project. Otherwise, this data will be collected within the first year of the DPhil project. The study designs are as follows. A cross-sectional survey of 600 individuals in 300 households from 10 villages will be completed. To measure infection status/intensity and morbidities, one child (aged 5+ years) and one adult (aged 18+ years) will be sampled from each household. Key morbidities to be diagnosed include malnutrition, anaemia, hepatosplenomegalies, liver fibrosis, and diarrhoeal outcomes. Household surveys to collect additional health information, socioeconomic data, and water, sanitation, and hygiene factors will be completed for all individuals aged 1+years within the 300 sampled households. Additional health outcomes to be measured from household surveys include other endemic infectious diseases and non-communicable diseases from medical histories as well as current and past clinical symptoms. Data will be available for approximately 1500 individuals from the cross-sectional household surveys. The DPhil candidate will have the opportunity to contribute to the existing fieldwork study designs through follow-up studies.
- Identify common clusters of morbidities associated with schistosomiasis infections
- Assess how multimorbidity prevalence varies by schistosomiasis prevalence and intensity
- Examine the variation in multimorbidities over a lifespan by assessing the variation against age in a cross-sectional manner.
The student will gain skills in literature review, study design, primary data collection, clinical epidemiological data analysis, statistical programming, data cleaning, and research presentation. Training in schistosomiasis epidemiology and fieldwork will be provided.
FIELD WORK, SECONDMENTS, INDUSTRY PLACEMENTS AND TRAINING
This project requires approximately 1-2 months of fieldwork in rural Uganda over the course of the DPhil project. The study is in close collaboration with the Uganda Ministry of Health. Experienced field teams from Uganda will co-lead the primary data collection with the primary supervisor.
Candidates ideally will have postgraduate training in global health, epidemiology, or a related discipline as well as experience in statistical/quantitative analyses of health data. Interest in parasitic infections and good communication skills are necessary.