The role of lambs, time and space in persistence of Dichelobacter nodosus, the causal agent of footrot

Lead Research Organisation: University of Warwick
Department Name: School of Life Sciences

Abstract

Footrot is an endemic disease of sheep in Great Britain, which is detrimental to the health and welfare of individual sheep, and the economics of the farm due to losses in production and costs of disease control. While control of footrot appears to be improving, it remains an endemic problem, with a global mean period prevalence of 5% found in 2013 (Winter et al., 2015). However, farmers report an epidemic aspect to the disease- with an epidemic occurring in lambs in the spring time. This project aims to address the reasons behind why this occurs.
There are four possible hypotheses for the epidemic of footrot in lambs in spring. The first is that lambs are born with passive immunity to footrot, which then wears off by spring time, resulting in the epidemic. The second is that the contact structure within the flock is altered as a result of the birth of the lambs. Norton et al., (2012) found an overall increase in connectivity within flocks as a result of the presence of lambs and increased contact rates can result in increased transmission of disease. The third is that the the increase in density of the flock due to the birth of lambs may sufficient in itself to create an epidemic. Finally, the spring climate may be more conducive to the spread of footrot than at other times of the year.
This project will investigate these hypotheses, firstly by using an existing dataset, and then designing a longitudinal observational study. Patterns of disease severity and risks for occurrence in lambs will be described, and then the impact of lambs on the incidence rate of footfot in ewes and lambs will be investigated. The results of this analysis will influence the design of the longitudinal study, where occurrence of lameness, climate data and spatial location and contact patterns between ewes and lambs will be recorded. This will improve understanding of the spread of disease, allowing an evidence based approach to be formulated for management of footrot in in spring time.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M01116X/1 01/10/2015 30/09/2023
1937618 Studentship BB/M01116X/1 02/10/2017 30/09/2021 Katharine Eleanor Lewis
 
Description The project has highlighted some novel behaviour of farmers when treating lambs. Models created from a survey of 1271 flocks in 2013 highlighted non-linear effects of treatment, where farmers were more likely to use parenteral antibiotics to treat lambs when >2-5% of lambs were lame compared with =2%. Flocks where large numbers of lambs (>10%) were lame were likely to delay treatment by considering only sheep with high (>2) locomotion scores as lame, and in addition practised inappropriate footbathing, culling of lame sheep and biosecurity. A further questionnaire, collected in 2018, will validate these risk factors. This could lead to improved advice available to farmers on treatment of lambs, which could impact the prevalence of lameness seen in ewes in the flock, namely that prompt, appropriate treatment with antibiotics is likely to lead to lower prevalence of lame lambs, and overall reduced antibiotic use. A paper on this topic has been submitted.
Exploitation Route The work could lead to further investigation of the use of antibiotics in lambs, and definition of a "best practice" treatment for lambs with footrot.
Sectors Agriculture, Food and Drink

 
Description Ruminant Health Meeting (Nottingham University) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact A talk was presented to an audience consisting of researchers (from PhD Students to Principal Investigators) involved in ruminant health. There was opportunity for questions, and the work presented was one of the first to identify unusual behaviour of farmers and use of antibiotics in lambs.
Year(s) Of Engagement Activity 2019
 
Description Social Network Analysis workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact The workshop was an opportunity to learn some of the latest tools in analysis of social networks, and a mini-conference was incorporated into the workshop. A talk was given called "Investigating the role of contact between ewes and their lambs in transmission of footrot in a flock of sheep in England", and a poster on the same work was presented.
Year(s) Of Engagement Activity 2020