A spatial and temporal analysis of Shiga-toxin producing Escherichia coli O157 and severe acute respiratory syndrome coronavirus 2 infection in England.

Elson, Richard (2022) A spatial and temporal analysis of Shiga-toxin producing Escherichia coli O157 and severe acute respiratory syndrome coronavirus 2 infection in England. Doctoral thesis, University of East Anglia.

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Abstract

Incorporating the domains of space and time to the analysis of infectious diseases can reveal unseen structure that may elucidate the mechanisms leading to infection. Spatial statistical methods have been available for many years, but they are not used routinely for surveillance purposes or for risk assessment during outbreaks. The primary aims of this thesis were to identify high or low risk areas of STEC O157 and SARS-CoV-2 in England; examine the spatial relationship between STEC O157 case density and environmental and socio-demographic risk factors and investigate the relationship between individual exposure to risk factors and residence in areas considered high risk for STEC O157. This was achieved using non-parametric smoothing techniques and multivariable negative binomial and logistic regression models

We identified areas of England where the risk of STEC and SARS-CoV-2 infection was significantly increased accounting for the underlying population at risk. For SARS-CoV-2, we describe the highly dynamic spatio-temporal risk at the start of the pandemic and show that widespread transmission was underway prior to lockdown in March 2020. For STEC O157, the risk of infection was greatest in the North, North West and South West of England.

Compared to baseline, STEC O157 risk was associated with cattle (Incidence rate ratio (IRR) 2.2, p<0.001) and sheep (IRR 1.7, p<0.001) density, rural residence (IRR 1.6, p<0.001) and presence of private water supplies (IRR 1.4 p=0.02) and we identified a novel association between sheep density and STEC O157 PT21/28 (IRR 2.8, p<0.001). Socio-economic status appeared to modify the risk related to travel outside the UK. Direct contact with the environment (Population attributable risk (PAR) 14%) and contact with dogs (PAR 12%) were important risk factors for residents of high-risk areas. Indirect contact with the environment (PAR 44%) and daytrips (PAR 37%) were more important for travellers. Residents of high-risk areas were less likely to report travel (adjusted Odds Ratio 0.56, p<0.001) suggesting that they acquired their infection close to home.

These results highlight the importance of considering spatial location and mobility when considering risks of infection. Identifying geographical areas that present an increased risk of infection allows public health messages to be targeted at residents and visitors.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Depositing User:	Chris White
Date Deposited:	27 Jun 2023 07:40
Last Modified:	27 Jun 2023 07:40
URI:	https://ueaeprints.uea.ac.uk/id/eprint/92501
DOI:

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