Overuse of antimicrobials is making these vital medicines less effective, posing a risk to human and animal health. But our understanding of how and where antimicrobials are being used is limited. This means we cannot easily predict how antimicrobial resistance will evolve.
For her PhD, Carys Redman-White is looking at new ways to use existing data to anticipate how antimicrobial use and antimicrobial resistance are advancing, which can inform future efforts to tackle this challenge.
What evidence gap is your project addressing?
The human health burden of bacterial antimicrobial resistance (AMR) disproportionately affects low-and middle-income countries, particularly in sub-Saharan Africa (see figure below), but it will take time to develop capacity for antimicrobial use (AMU) and AMR surveillance in humans, livestock, and other domestic animals in these settings. In the meantime, we need ways to model and predict AMU and AMR where data are scarce, in order to guide interventions.
For my PhD, I am developing ways to use existing data to investigate AMU and AMR in livestock in sub-Saharan Africa, as AMU in livestock accounts for a substantial portion of total antimicrobial consumption worldwide and the health of these animals is key for the nutrition, health, and livelihoods of those who keep them.
What methods are you using?
There are many reasons why farmers use antimicrobial drugs in livestock – from local prevalence of livestock diseases, to availability of veterinary services, to macroeconomic effects on the costs of veterinary drugs. Antimicrobial use is a key driver of antimicrobial resistance but many other factors also play into this, such as water and sanitation facilities, and movements of wild animals such as migrating birds. My first steps to modelling this involve disentangling these drivers and the relationships between them. Such a complex system lends itself well to a system dynamics approach, which is a quantitative modelling method designed to make sense of systems with many interlinking aspects.
What are some of the early insights from your work?
My research so far has highlighted the importance of One Health interdisciplinary approaches, and appreciation of the structural as well as individual factors affecting antimicrobial use and development, and the spread of resistance – these don’t occur in a vacuum! I’ve also come across some surprising gaps in the literature. For example, we know that vaccines are extremely important to human and animal health, but there is a need for more direct research into the impacts of livestock vaccination on AMU and AMR in these species.
What are your next steps?
My current focus is on developing a semi-quantitative causal loop diagram (CLD) model of the drivers of AMU and AMR in livestock – this will form an important stepping-stone to building a system dynamics model incorporating quantitative data from the published literature on the relationships between factors impacting livestock AMU and AMR.
How does this fit into wider efforts to understand AMU and AMR in LMICs?
People in low-and middle-income countries face many challenges which also drive AMU and AMR. For example, people in rural areas may have limited access to animal health services, and infrastructure may be inadequate. My work draws on a broad swathe of the existing research into socio-economic, political, and epidemiological landscapes in LMICs and the ways in which they affect the health of humans, animals, and the environment.
I was recently lucky enough to attend the World One Health Congress in Singapore, where researchers from across the globe were presenting their AMR and One Health work using techniques ranging from metagenomics to political economy analysis. There were some fantastic discussions between people across disciplines, and lots of enthusiasm for sharing data and collaborating.
Carys Redman-White is a PhD student working with SEBI-Livestock and the Global Academy of Agriculture and Food Systems, based at the University of Edinburgh’s Royal (Dick) School of Veterinary Studies. She is studying with the EASTBIO Doctoral Training Partnership.