The role of Fusobacterium necrophorum in sheep and the environment in the severity and persistence of footrot
Footrot is an infectious dermatitis of the ovine foot which causes severe lameness, resulting in poor welfare and decreased productivity. It is an economically important disease, costing the UK sheep industry approximately £80 million per annum. The causal agent of footrot is Dichelobacter nodosus, however the disease is actually thought to be polymicrobial. Fusobacterium necrophorum is closely associated with footrot but its role in disease initiation and persistence is not fully understood: it is considered either a necessary precursor or a secondary pathogen that increases the severity and chronicity of footrot.
F. necrophorum is a pleomorphic, Gram-negative, anaerobic bacterium. It is a common opportunistic pathogen that causes a variety of necrotic diseases in a wide range of host species, including hepatic abscess and interdigital necrobacillosis in cattle, periodontal disease in macropods and Lemierre’s disease humans.
The source of F. necrophorum infection in ovine footrot is assumed to be environmental, but there is little evidence for the presence of F. necrophorum on pasture or in sheep faeces. It is also unknown whether, if present, it can persist in these sites.
The aims of my research are:
- To identify sites in the environment of sheep (foot skin/horn, gum, faeces, pasture) where F. necrophorum is present.
- To establish whether F. necrophorum persists at any of these sites.
- To compare the presence and persistence of F. necrophorum with the incidence and prevalence of footrot in feet, sheep and flocks
- To compare the presence and persistence of F. necrophorum with the presence and persistence of D. nodosus.
In order to detect and quantify F. necrophorum in samples taken from sheep and the environment I will be using quantitative PCR. I will also develop a strain typing method in order to study the persistence and diversity of F. necrophorum at different sites.
The results of my research should increase our understanding of the role of F. necrophorum in the epidemiology of ovine footrot.
NERC CASE Studentship
AHDB Beef & Lamb Industrial CASE partner
Ruminant Research Bursary funded by MSD Animal Health
Professor Laura Green
Epidemiologist, Life Sciences, University of Warwick
Laura dot Green at warwick dot ac dot uk
Dr. Kevin Purdy
Microbial Ecologist, Life Sciences, University of Warwick
K dot Purdy at warwick dot ac dot uk
Dr. Liz Genever
AHDB Beef & Lamb Research and Development Manager/Student Liason
Liz dot Genever at ahdb dot org dot uk