Details of Award
NERC Reference : NE/K007491/1
AGRIFOOD: The holy grail of footrot in sheep: persistence of Dichelobacter nodosus, the causal agent of footrot in sheep
Training Grant Award
- Lead Supervisor:
- Professor LE Green, University of Warwick, School of Life Sciences
- Grant held at:
- University of Warwick, School of Life Sciences
- Science Area:
- Terrestrial
- Overall Classification:
- Terrestrial
- ENRIs:
- Environmental Risks and Hazards
- Global Change
- Science Topics:
- None
- Abstract:
- Footrot is present in over 95% sheep flocks in GB, causing 7 million cases of lameness per year and costing the industry approximately #84 million per annum. The causal agent, Dichelobacter nodosus (Dn), is an obligate anaerobe with a tiny genome that recombines frequently. It causes an inflammation of the epidermis of the foot that makes sheep lame. Lameness reduces their productivity, thus impacting on their health and welfare and sheep farming sustainability. In the UK footrot is endemic and appears as a series of mini-epidemics throughout the year. In countries with hot, dry periods of weather (Australia, India, Southern Europe) or cold dry periods (North Scotland, northern Europe) footrot presents as major epidemics with periods where it disappears and sheep feet are not diseased. In certain arid conditions footrot has been eliminated from flocks and regions but in many areas elimination seems impossible, despite periods of time where there are no diseased sheep. A question that has remained unanswered to date is, where does D. nodosus persist in these situations? Research from a NERC CASE studentship at Warwick has indicated that the load of Dn is undetectable or low on healthy feet and increases in load of Dn on the foot trigger disease. These results came from a 5-week study of sheep in a period of transmission of D. nodosus. Other work from Warwick indicates that Dn is not present on newborn lambs' feet when sampled before they touch the ground, but it is present a few hours later. Dn has been isolated at one point in time from soil where sheep have recently (minutes before) stood, but not from areas around feeding troughs or gates (i.e. areas where sheep frequently walk or stand), faecally contaminated bedding and most intriguingly, the gingival crevice (tooth - gum junction) in the mouth. EBLEX are acutely aware that identification of the site of persistence of D. nodosus would contribute to our understanding of this important endemic disease and inform on approaches for control and possibly elimination of footrot in GB where conditions for persistence are good. The hypothesis for this proposal is that there is at least one site where Dichelobacter nodosus persists when there are no diseased sheep in a flock for many months, sub hypotheses are that: the number of sites where persistence occurs decreases as the environmental conditions become less conducive to footrot and as the time from the last diseased sheep increases (e.g it is lost initially from soil, then faecally contaminated bedding/ground, then feet, then mouth). We propose that the student uses PCR and molecular typing tools such as MLVA to investigate sites where D. nodosus persists and qPCR to investigate whether and how load of D. nodosus and levels of disease and sites are temporally associated. Year 1: the student will learn existing techniques on qPCR and MLVA and isolation of D. nodosus at Warwick. Using ten ewes with feet and moth swabs collected at 14 day intervals over two months they will develop statistical techniques that differentiate persistence from contamination. Assuming the hypothesis is correct the student will progress to years 2 and 3 as below: Year 2: using techniques from year 1 the student will sample ewes and their environment from autumn to spring, sample their lambs as they are born and so provide evidence for sites and duration of persistence Year 3: the student will visit Scotland and Spain at times of transmission and no transmission and collect samples from small flocks with known infection with footrot. All sheep will be sampled and the sites of carriage elucidated. Should the results from year 1 deviate from the hypotheses new hypotheses will be developed on persistence and the direction of the project will change accordingly.
- NERC Reference:
- NE/K007491/1
- Grant Stage:
- Completed
- Scheme:
- DTG - directed
- Grant Status:
- Closed
- Programme:
- Open CASE
This training grant award has a total value of £73,670
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - RTSG | Total - Student Stipend |
|---|---|---|
| £13,978 | £10,500 | £49,194 |
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