Biology subjects

Peters, A. R.

Publications and source records attributed to Peters, A. R..

3 recordsLinked to original sources

bioRxiv2025

A socio-ecological System Dynamics model of antimicrobial use and resistance

The concept of resource extraction in the context of antimicrobial resistance (AMR) is rarely explored. In this framework, antimicrobial susceptibility is viewed as a finite resource that is depleted through the use of antimicrobials --thus, AMR represents the exhaustion of this resource. In this work, we examine the system dynamics of AMR using causal loop diagrams to define both the structure and behaviour of two variants of the system. We then evaluate the robustness of the system dynamics models through sensitivity testing. The first model is inspired by a classic "Limits to Growth" structure, in which antimicrobial use practices depend on recent observations of treatment success or failure. The second differs by including AMR surveillance informing antimicrobial prescribing instead of anecdotal experience. The models consider one "bug-drug-mutation-context" combination at a time, but can be applied to different microbes, antimicrobials, and host populations in human or veterinary contexts. Multiparameter sensitivity analyses of relative fitness and timescale parameters were carried out on both model variants. Several key differences in model behaviour over time were observed between the socio-ecological Limits to Growth structure and the modified version in which human judgment, with its associated time lag, is bypassed. The models help explore the effects of human behaviour and associated time lags on patterns of population-level antimicrobial susceptibility over time, applying an established modelling technique in a novel context to generate new insights - notably that plateaux in AMR observed in the field could be in part due to human behaviour rather than purely evolutionary forces. The framing of antimicrobial susceptibility as a variably renewable natural resource is valuable not only as an avenue for alternative modelling approaches, but also as a more collaborative framing for public and policy engagement to promote sustainable management of this common pool resource.

microbiology↗

bioRxiv2022

Systematic map of the most recent evidence (2010 to 2019) on ruminant production-limiting disease prevalence and associated mortality in Ethiopia

Ethiopias livestock sector supports the livelihoods of millions of smallholder farmers. However, despite the improvements of recent years, livestock productivity remains low due to critical constraints, including infectious diseases. The aim of this study was to collate and synthesise the published evidence on ruminant disease frequency and disease-associated mortality in Ethiopia, by identifying knowledge gaps and clusters in the literature to provide the basis for a decision-making tool. Searches on both bibliographic and organisation databases were conducted in English and were restricted to the period 2010-2019. Search results were screened for relevance at title, abstract and full text level, which identified 716 articles relevant to the research question. The systematic map revealed an increased publication output from 2012-2017, compared to 2010-2011 and 2018-2019. Most studies were conducted in Oromia, Amhara and SNNPR. A substantial body of evidence was found for trypanosomosis, ectoparasite infestation, fasciolosis, nematodiasis, echinococcosis, brucellosis and bovine brucellosis. This study suggests that despite the high output of epidemiological publications, further understanding of a considerable number of diseases is required and where evidence is abundant, synthesis of information should be carried out in order to better inform decisions on disease control priorities in the livestock sector.

scientific communication and education↗

bioRxiv2022

Patterns of mortality in domesticated ruminants in Ethiopia

BackgroundIn Ethiopia, there are limited data on the causes of ruminant mortality and reproductive losses which is hampering the development of interventions to improve livestock health. The present study aimed to establish the causes and magnitude of mortality and reproductive losses in cattle, sheep and goats across all smallholder production systems in Ethiopia. MethodsThe study, consisting of three data sources, was conducted to collect data on mortality and reproductive losses in cattle, sheep and goats. Nine regional states; Afar, Amhara, Benishangul Gumuz, Gambela, Harari, Oromia, Southern Nations, Nationalities, and Peoples Region, Somali, and Tigray were surveyed, as well as the city administrations of Dire Dawa and Addis Ababa. Questionnaire surveys were conducted with farmers and key stakeholders, as well as data collected from regional diagnostic laboratories. Data from the Living Standards Measurement Study were also included. Generalised linear mixed and hurdle models were used for data analysis, with results summarized using predicted outcomes. ResultsAnalyses indicated that most herds experienced zero mortality and reproductive losses, with rare occasions of larger losses. Diseases causing deaths varied greatly both geographically and over time. There was little agreement between the different datasets. While the models aid the understanding of patterns of mortality and reproductive losses, the degree of variation observed limited the predictive scope. ConclusionsThe models revealed some insight into why mortality rates are variable over time and are therefore less useful in measuring production or health status, and it is suggested that alternative measures of productivity, such as young stock mortality, would be more stable over time and likely more indicative.

bioinformatics↗