Environmental reservoirs of bovine tuberculosis; causal agent of bovine TB

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

Abstract

The bacterial pathogen, Mycobacterium bovis has one of the broadest host ranges of all pathogens, with a wide range of wildlife and domestic animals infected across the world. It can also infect humans. It is the impact on wildlife of M. bovis, in the context of herd breakdowns that this project focuses on. The aim is to study infection, transmission and the effect of vaccination within the European badger (Meles meles) as a model animal host. The study will address the relationship between badger densities, infectious disease states of bovine tuberculosis by using faecal shedding as a proxy for tracheal shedding in a defined population comprised of many social groups in areas of high, medium and low herd breakdown.
Thus we hypothesise that a combined strategy of vaccination, combined with strategic monitoring of faecal shedding using the badger latrine as the unit of sampling, will prove to be a viable long-term strategy for the reduction of bTB in badger populations in the UK. We hypothesise that infectious animals with bTB disease can be detected through faecal monitoring and these will be responsible for not only indirect, but also direct transmission of infection. This challenges existing, invasive, monitoring approaches and instead relies on faecal monitoring as a true indicator of disease risk. We suggest that only a small proportion of the badgers contribute to environmental contamination and disease transmission. The third hypothesis is that the social group composition, extent of ranging of animals, as well as the proximity to neighbouring groups are key drivers of the prevalence of strains of M. bovis. Our final hypothesis is that vaccine delivery reduces not only the infection prevalence of animals but that it also has a significant impact on shedding and also decreases pathogen diversity. Through molecular forensic techniques the aim is to determine the effects of the vaccine on the individual, social group and population level to be compared in the different vaccination zones.

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
1643138 Studentship BB/M01116X/1 05/10/2015 30/09/2019 Sian Powell
 
Description Clustering of bTB by badger social group and that this is stable throughout multiple survey periods, across the seasons. Forms basis of an argument for a test and cull approach, as well as environmental contamination requiring tackling.

M bovis survival is effected by season. The qPCR method employed was not reliable on non-fresh samples due to the non-homogenous degradation of M.bovis DNA in the faecal sample.

Viability based qPCR is too expensive when optimised to employ as a standard, high-throughput technique.
Exploitation Route Direct future research, and save people a lot of time/money from trying to optimise PMA methods.

I would like future work to expand on the current farm-clustering situation, to see if other farms resemble this when there is a stable badger population away from a cull zone. This adds weight to the targeted cull argument, as well as the dangers of the perturbation effect.
Sectors Agriculture, Food and Drink

 
Description My badger survey/bTB survey has been widely used by Dr. Sibley and the SaveMe trust on their project farm in Devon. Badger survey data was published as part of the work by Mr. Sibley. Landowner has used my bTB findings in Gloucestershire to implement biosecurity measures and also to rationalise to his neighbours why he did not want to participate in a badger cull on his land. Been asked to present at the BCVA later this year.
First Year Of Impact 2018
Sector Agriculture, Food and Drink
Impact Types Societal

 
Description Cited in work by Richard Sibley and in his campaign to tackle bTB in cattle.
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Participation in a advisory committee
Impact Project farm established at Gatcombe Farm in Devon to trial new methods for the detection of bovine tuberculosis in the cattle population, as well as vaccination of the local badger population. Government allowed this to proceed.
 
Description Farm visit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Discussing with local farmers what work I was doing on their neighbours farm. Presenting what I was doing there (surveying and testing)
Year(s) Of Engagement Activity 2018
 
Description Poster at symposium. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact Presentation of work so far. Including field work and a focus on the issues surrounding the reliable quantification of viable cells from environmental samples.
Year(s) Of Engagement Activity 2017
 
Description Public Science Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Discussing the microbiome. My section was on the badger faecal (and gut) microbiome and then the obvious discussion which always arises once you use the word 'badger' - expressed my personal opinion on the potential effectivity of the cull and transmission issues. Spoke to A-level students who are interested in veterinary and those that are interested in ecology.
Year(s) Of Engagement Activity 2017