Principal Supervisor name and department: Professor Laura Green, School of Life Sciences, Warwick
Second Supervisor name and department: Dr Kevin Purdy, School of Life Sciences, Warwick
Where will the student be based? Warwick
PhD project title: The role of lambs in transmission and persistence of footrot in sheep
Project description:
Footrot is the major cause of lameness in sheep in the UK, costing the industry £84 million per
annum and causing lameness in up to 9 million sheep each year. Footrot is caused by the bacterium
Dichelobacter nodosus. As well as affecting adult sheep footrot affects lambs from a few weeks of
age, many farmers report an epidemic of lameness in lambs in Spring; this typically presents as a mild
form of footrot but slows the growth of affected lambs considerably.
We have data from approximately 150 lambs born to 98 ewes that were monitored from birth to
weaning. Each week all ewes and lambs locomotion was scored. In addition lame lambs and ewes
were examined and a sample from the foot lesion was taken using swabs that were stored at -80oC
for molecular analysis and used for bacterial culture. D. nodosus isolates from culture have been
analysed for three molecular features possibly associated with pathogenicity or persistence. Fifty
lambs were also examined in more detail each week over a 4-week period and foot lesion and swab
data collected.
The aim of this PhD is to analyse this complex longitudinal dataset using advanced statistical methods
to investigate the associations between lameness in ewes and their offspring and the pattern of
disease spread over time together with the results from analysis of the isolates to test the hypothesis
that lambs are important n the spread and persistence of footrot.
Once key patterns have been identified from lameness and lesion data specific swab samples will be
targeted for microbiological analysis to investigate changes in the structure of the microbial
community on the infected feet, focusing in particular Dichelobacter nodosus, using molecular
fingerprinting and possibly pyrosequencing.
Should time allow a further on-farm study will be designed to test hypotheses that arise from the
above experiments. For example, investigating mixing patterns of lambs on farm using electronic
collars that record contact between animals.
Key experimental skills involved:
Advanced statistical modelling and Bayesian analysis, epidemiology and development of skills in
understanding infectious disease transmission, molecular biology and downstream analysis of
molecular data and integration of molecular microbial data into epidemiological analyses.
References:
2012, Foddai, Alessandro; Green Laura E.; Mason, Sam A.; Kaler, Jasmeet, Evaluating observer
agreement of scoring systems for foot integrity and footrot lesions in sheep, BMC
VETERINARY RESEARCH, 8, 0
2012, Oakley, B.B., Carbonero, F., Dowd, S.E., Hawkins, R.H., and Purdy, K.J. Contrasting patterns of
niche partitioning between two anaerobic terminal oxidizers of organic matter. ISME
JOURNAL, 6, 905, 914, 2.
2011, Calvo-Bado, Leo A.; Oakley, Brian B.; Dowd, Scot E.; Green Laura E.; Medley, Graham F.; UlHassan, Atiya; Bateman, Vicky; Gaze, William; Witcomb, Luci; Grogono-Thomas, Rose; Kaler,
Jasmeet; Russell, Claire L.; Wellington, Elizabeth M. H., Ovine pedomics: the first study of the
ovine foot 16S rRNA-based microbiome, ISME JOURNAL, 5, 1426, 1437, 0
2011, Kaler, J.; George, T. R. N.; Green L. E., Why are sheep lame? Temporal associations between
severity of foot lesions and severity of lameness in 60 sheep, ANIMAL WELFARE, 20, 433,
438, 1
2011, Calvo-Bado, Leo A.; Green Laura E.; Medley, Graham F.; Ul-Hassan, Atiya; Grogono-Thomas,
Rose; Buller, Nicky; Kaler, Jasmeet; Russell, Claire L.; Kennan, Ruth M.; Rood, Julian I.;
Wellington, Elizabeth M. H., Detection and diversity of a putative novel heterogeneous
polymorphic proline-glycine repeat (Pgr) protein in the footrot pathogen Dichelobacter
nodosus, VETERINARY MICROBIOLOGY, 147, 358, 366, 1
2010, Kaler, J.; Medley, G. F.; Grogono-Thomas, R.; Wellington, E. M. H.; Calvo-Bado, L. A.; Wassink,
G. J.; King, E. M.; Moore, L. J.; Russell, C.; Green L. E., Factors associated with changes of
state of foot conformation and lameness in a flock of sheep, PREVENTIVE VETERINARY
MEDICINE, 97, 237, 244, 7
2010, Wassink, G. J.; King, E. M.; Grogono-Thomas, R.; Brown, J. C.; Moore, L. J.; Green L. E., A within
farm clinical trial to compare two treatments (parenteral antibacterials and hoof trimming)
for sheep lame with footrot, PREVENTIVE VETERINARY MEDICINE, 96, 93, 103, 14
2010, Kaler, J.; Daniels, S. L. S.; Wright, J. L.; Green L. E., Randomized Clinical Trial of Long-Acting
Oxytetracycline, Foot Trimming, and Flunixine Meglumine on Time to Recovery in Sheep with
Footrot, JOURNAL OF VETERINARY INTERNAL MEDICINE, 24, 420, 425, 17
2009, Kaler, J.; Wassink, G. J.; Green L. E., The inter- and intra-observer reliability of a locomotion
scoring scale for sheep, VETERINARY JOURNAL, 180, 189, 194, 15
2008, Green L. E.; George, T. R. N., Assessment of current knowledge of footrot in sheep with
particular reference to Dichelobacter nodosus and implications for elimination or control
strategies for sheep in Great Britain, VETERINARY JOURNAL, 175, 173, 180, 14
2007, Green L. E.; Wassink, G. J.; Grogono-Thomas, R.; Moore, L. J.; Medley, G. F., Looking after the
individual to reduce disease in the flock: A binomial mixed effects model investigating the
impact of individual sheep management of footrot and interdigital dermatitis in a
prospective longitudinal study on one farm, PREVENTIVE VETERINARY MEDICINE, 78, 172,
178, 17
2005, Purdy, K.J. Nucleic acid recovery from complex environmental samples. METHODS IN
ENZYMOLOGY 397, 271, 292, 20.
2005, Moore, LJ; Wassink, GJ; Green LE; Grogono-Thomas, R, The detection and characterisation of
Dichelobacter nodosus from cases of ovine footrot in England and Wales, VETERINARY
MICROBIOLOGY, 108, 57, 67, 24
2004, Wassink, GJ; Grogono-Thomas, R; Moore, LJ; Green LE, Risk factors associated with the
prevalence of interdigital dermatitis in sheep from 1999 to 2000, VETERINARY RECORD, 154,
551, 556, 13
2003, Wassink, GJ; Grogono-Thomas, R; Moore, LJ; Green LE, Risk factors associated with the
prevalence of footrot in sheep from 1999 to 2000, VETERINARY RECORD, 152, 351, 358, 36
Contact details for application enquiries:
Professor Laura Green, Email: laura.green@warwick.ac.uk
Keywords: Epidemiology, Statistics, Molecular Biology, Footrot, Lameness, Sheep
Please state below which hazards may be connected with this studentship:
The studentship will entail work involving:
√ if applies
Chemicals – high toxicity and category 1 or 2 substances
Organo-phosphate or carbamate pesticides
Skin or respiratory sensitising agents (e.g. insect parts, organic
dusts from animals, spores, pollen, antibiotics, fibres, chemical
sensitisers, wood dust etc)
Radionuclides
Significant manual handling
√
Mechanical repetition where the frequency and duration are
significant
Working in areas where there are temperature extremes
Driving vehicles (tractors, fork lifts, ATVs etc)
Crop planting, harvesting, recording or grading
Working in close proximity to bees or other stinging insects
Working at height [>2 m] (using various types of access
equipment)
Working with noisy or vibrating equipment
Working at night (between 11.00pm and 6.00am)
Food handling
√
Other significant hazards (specify)
Handling sheep