Biology subjects

Rawson, T.

Publications and source records attributed to Rawson, T..

4 recordsLinked to original sources

bioRxiv2021

Mechanisms of biodiversity between Campylobacter sequence types in a flock of broiler-breeder chickens.

A long-term study of Campylobacter sequence types was used to investigate the competitive framework of the Campylobacter metacommunity, and understand how multiple sequence types simultaneously co-occur in a flock of chickens. A combination of matrix and patch-occupancy models were used to estimate parameters describing the competition, transmission, and mortality of each sequence type. It was found that Campylobacter sequence types form a strong hierarchical framework within a flock of chickens, and occupied a broad spectrum of transmission-mortality trade-offs. Upon further investigation of how biodiversity is thus maintained within the flock, it was found that the demographic capabilities of Campylobacter, such as mortality and transmission, could not explain the broad biodiversity of sequence types seen, suggesting that external factors such as host-bird health and seasonality are important elements in maintaining biodiversity of Campylobacter sequence types.

microbiology↗

bioRxiv2021

Can good broiler flock welfare prevent colonization by Campylobacter?

Using data on rearing and welfare metrics of multiple commercial broiler flocks from the last ten years, we investigate how welfare measures such as hock burn, mortality, weight, and pododermatitis, among others, impact the likelihood of a flock becoming colonized by Campylobacter. Using both logistic regression and Bayesian networks, we show that, while some welfare metrics were weakly related to Campylobacter colonization, evidence could not be found to suggest that these metrics actively exacerbated Campylobacter colonization, rather that they were both symptoms of the same underlying cause. Instead, observed dependency on the management of the flock suggested that yet-undiscovered differences in rearing practise were the principal cause of both poor bird welfare and increased risk of Campylobacter, suggesting that action can be taken to improve both these factors simultaneously.

microbiology↗

bioRxiv2020

A mathematical modelling approach to uncover factors influencing the spread of Campylobacter in a flock of chickens

Despite continued efforts into improving biosecurity protocol, Campylobacter continues to be detected in the majority of commercial chicken flocks across Europe. Using an extensive data set of Campylobacter prevalence within a chicken breeder flock for over a year, multiple Bayesian models are presented to explore the dynamics of the spread of Campylobacter in response to seasonal variation, species-specificity, bird health and total infection prevalence. It was found that birds within the flock varied greatly in their response to bacterial challenge, and that this phenomena had a large impact in the overall prevalence of different species of Campylobacter. Campylobacter jejuni appeared more frequently in the summer, while Campylobacter coli persisted for a longer duration, amplified by the most susceptible birds in the flock. Our study suggests that strains of Campylobacter that appear most frequently likely possess no demographic advantage, but are instead amplified due to the health of the birds that ingest it.

microbiology↗

bioRxiv2019

A mathematical model of Campylobacter dynamics within a broiler flock

Globally, the bacterial genus Campylobacter is one of the leading causes of human gastroenteritis, with its primary route of infection being through poultry meat. Despite decades of study we appear to be no closer to preventing outbreaks within commercial chicken flocks, and the application of biosecurity measures is limited by a lack of understanding of the transmission dynamics within a flock. Our work is the first to undertake a mathematical modelling approach to Campylobacter population dynamics within a flock of broilers (chickens bred specifically for meat). A system of stochastic differential equations is used to investigate the diverse and fluctuating conditions within the gut of a broiler, and models the routes of infection between co-housed birds. The presented model provides mechanistic explanations for key infection dynamics that have been long-observed but very poorly understood. We highlight several driving mechanisms behind observed infection phenomena, simulate experimentally observed inter-strain competition, and present a promising approach to hypothesising new methods of preventing flock outbreaks.\n\nAuthor summaryThe bacteria Campylobacter is one of the most common causes of food poisoning globally. The most common route of infection is through raw chicken meat, as a result of many chicken farms across the world housing fully infected flocks. Despite the magnitude of this public health risk, little is understood of the specifics of how chickens become infected, and the ways that they then infect one another. Our work presents a mathematical model of Campylobacter transmission dynamics within a flock of chickens. We compare the results of the model to real world data sets, explore key dynamical behaviours, and present a sensitivity analysis to highlight the most important factors underpinning outbreaks.

systems biology↗