Bovine ischaemic teat necrosis: combating a severe, emerging disease of economic importance

Bovine ischaemic teat necrosis (ITN) is a severe disease of dairy cattle with unknown aetiology and is rapidly increasing in prevalence. ITN frequently results in teat loss making it a substantial animal welfare issue with subsequent animal culling causing substantial economic losses.
*Through preliminary microbiological analyses we identified a high association for treponemes, fastidious bacteria typically found within bovine digital dermatitis (DD) lesions, with bovine ITN whilst finding no evidence for herpesvirus or papillomavirus.
*The aetiology of ITN requires further clarification. Metagenomics can clarify diversity and abundance of disease associated microorganisms and recent high throughput sequencing technology allows global shotgun metagenomic sequencing of entire DNA complements which can implicate or rule out the contribution of a range of microorganisms including bacteria, viruses and fungi.
*Whilst a pilot epidemiological study (see BBSRC remit section) begins to delineate relationships, a larger study is now needed to ascertain comprehensive between and within farm prevalence of ITN for the UK, to clarify the underlying risk factors and identify treatment options.
*This project would partner with the UK Dairy Levy Board (AHDB Dairy), who recognise ITN as a severe emerging disease of economic importance, to use systems/data driven biology together with a range of complementary applied approaches to combat ITN.

*Project hypotheses: 'i) there is a specific microbial consortium responsible for ITN & ii) there are specific risk factors associated with ITN'.

*Research questions: 'a) what are the key microorganisms responsible for ITN & their associated infection reservoirs & b) what are the risk factors?'

Aims and timelines:
1) Identify key associated pathogens in ITN lesions (Months 1-26). Shotgun metagenomics for in depth data describing potential pathogens. Detailed histopathology studies to delineate ITN aetiology including immunohistochemistry of DD treponemes.
2) Determine farmer reported prevalence and risk factors associated with ITN via postal questionnaire (Months 1-32). Generate comprehensive epidemiological data and enable risk factor identification allowing for potential control methods/guidelines to be developed.
3) Develop diagnostic pathogen PCR assays to analyse further ITN lesions, the host environment and faeces (Months 24-36). Diagnostic PCR assays allow greater numbers of ITN lesions to be investigated further delineating aetiology and then to identify infection reservoirs.
4) Use novel in vitro approaches towards control and/or treatment of disease (Months 33-43). Tailored to key pathogens identified in 1), risk factors and infection reservoirs in 2) and 3). To include pathogen susceptibility testing of novel disinfectants/antiseptics/antibiotics or investigations into equipment/environment decontamination.
5) Thesis write up (Months 46-48).

*Bovine ITN is a severe teat disease of dairy cattle and frequently results in extensive self-licking leading to destruction of the entire teat. First reported ten years ago, in the last two years there has been an increase in UK reported cases, resulting in severe animal welfare issues, a substantial number of affected cows culled and substantial economic losses.


*This project is extremely BBSRC relevant - it uses systems approaches and data driven biology to fundamentally understand complex biological processes to control an important emerging infectious disease. This should increase both animal health and welfare of these managed animals and reduce waste in the food chain strengthening food security with potential for technology development. Also involves collaborative research with users/stakeholders to inform policy/practice (AHDB Dairy).