A Novel Way to Detect Infection Status of Wildlife likely to have Bovine Tuberculosis (‘Badger Infection Forensics’)
Submitting InstitutionUniversity of Warwick
Unit of AssessmentBiological Sciences
Summary Impact TypeEnvironmental
Research Subject Area(s)
Agricultural and Veterinary Sciences: Animal Production, Veterinary Sciences
Medical and Health Sciences: Medical Microbiology
Summary of the impact
A novel, reliable, non-invasive and rapid method has been developed to
detect excretion of Mycobacterium bovis, the causal agent of
bovine tuberculosis (bTB), into the environment ("shedding") by wildlife
hosts. This test has been used to establish the efficacy of the bTB
vaccine on reducing environmental contamination by shedding of M.
bovis in the faeces (from January 2010). It has also become an
important monitoring tool used by VisaVet (European Veterinary Health
Surveillance), targeting bTB in wild boar and red deer (from July 2010) to
establish bTB reservoirs and take action to protect the cattle stocks.
Farmers will benefit and now be able to monitor environmental
contamination by M. bovis, which allows them to establish
biosecurity best practice.
The method includes both a presence/absence score and a quantitative
assay of infectious disease load in faecal matter in the environment. This
is the first standard assay to determine environmental contamination, the
main route for disease spread to cattle, and allows evaluation of the
impacts of vaccination, culling and increased movement of badgers during
disease- management strategies. This test also enables precise monitoring
of cattle herds infected with bovine tuberculosis (bTB) as it advances
from the South West to the North East of England.
Professor Elizabeth Wellington and Dr Orin Courtenay research groups in
the School of Life Sciences at the University of Warwick, have researched
the microbiology and epidemiology of bovine tuberculosis since 2002 (1).
Bovine Tuberculosis is one of the most intractable and challenging
problems facing UK scientists today and costs the UK Government £600-700
million per annum. If there is no improvement to the current methods of
testing and control in cattle herds, bTB is predicted to cost up to £1
billion in the UK over the next 10 years.
Bovine tuberculosis is caused by M. bovis. Although modern
practices prevent it from spreading to humans, it causes substantial
problems to the cattle farming industry. The incidence of infection seems
to be increasing despite attempts at control. Although testing and
slaughter programmes managed the incidence of bTB in the UK until around
20 years ago, control and eradication have become more difficult owing to
the persistent infection of badgers, which serve as a wildlife reservoir
of the disease. Badgers became a protected species in 1973 and are now
covered by the Protection of Badgers Act 1992; it is a legal requirement
to prove that animals are infected before control measures can be
implemented. The incidence of bTB in cattle herds in the UK and the
Republic of Ireland has increased from 0.05% of herds in the late 1970s to
2.7% in 2000, leading to serious economic and animal welfare issues. The
current level of infection in UK cattle is estimated to be over 10% (Blake
and Donnelly 2012). There is controversy over the sources of infection,
mechanisms of transmission and the most effective policies to contain the
disease. bTB is now spreading rapidly from the Southwest to the North and
East of England.
Wellington and collaborator Courtenay started work in 2006 identifying
and monitoring sources and risk of transmission by further establishing
that the transmission between cattle and badgers is most likely due to
environmental contamination. Monitoring viable M. bovis in badger
faeces on cattle pasture (2-7) and in badger populations, in 2007
established that M. bovis can survive for long periods of time
after being shed into the environment (1). Progressive infection in
badgers is correlated with the likelihood of culture-positive sputum,
faecal and urine samples, which are all potential sources of onward
transmission with between-sample correlations shown by bacteriology
(Delahay et al. unpublished data), and quantitative polymerase
chain reaction (qPCR) techniques (Travis et al. 2013, submitted).
The empirical risk of cattle infection from environmentally shed M.
bovis bacilli is illustrated by infection of naïve calves exposed to
pasture previously grazed by excreting cattle or previously seeded with
wild-type M. bovis (reviewed in (2)) and deer to cattle and deer
to deer transmission via excreta and shared food. The most important
source of infection to grazing cattle is likely to be the inhalation of
aerosolised bacilli following investigation or incidental ingestion of
badger excretions and average M. bovis loads in badger faecal
latrines measured by qPCR are 104 to 106 cells per
gram, which far exceeds the expected infectious dose (3, 7).
The group took the research further and, in collaboration with Eamonn
Gormley at University College Dublin, conducted a randomised trial of the
effect of giving oral BCG vaccines to wild badger populations on M.
bovis loads in faecal matter. The non-invasive molecular assay for
bTB shedding in badgers using faecal material was validated by an
extensive ring-trial between three laboratories including the Animal
Health and Veterinary Laboratories Agency (AHVLA), VisaVet (European
Veterinary Pathology Laboratory) and University College London (Mike
Taylor). The test will form part of the current Government's strategy to
control bTB in cattle.
University of Warwick Staff
Professor Elizabeth Wellington, Professor of Environmental
Microbiology, School of Life Sciences (1987 - present).
Dr Orin Courtenay, Epidemiologist, Reader, School of Life
Sciences (2005 - present).
Dr Eamonn Gormley, Veterinary Scientist, Senior Research
Associate, School of Veterinary Sciences, University College, Dublin.
Supplied badger faeces and tissue and infection statistics for
Dr Glyn Hewinson, Veterinary Scientist, Animal Health &
Veterinary Laboratories Agency (AHVLA), Addlestone, Surry, UK.
Collaborated in ring trial as second lab doing testing.
Dr Mike Taylor, Microbiologist, Collaborated in ring trial as
third lab doing testing.
Professor Luca Dominguez, Vet, VisaVet Health Surveillance
Centre, Madrid, Spain. Collaborated in ring trial as third lab doing
testing after Taylor.
References to the research
(1) Young, J. S., Gormley, E. and Wellington, E. M. H. (2005). Molecular
Detection of Mycobacterium bovis and Mycobacterium bovis
BCG (Pasteur) in Soil. Appl. Environ. Microbiol. 71, 1946-1952. Doi:
(2) Courtenay O., Wellington E. M. H. (2008). Mycobacterium bovis
in the environment: Towards our understanding of its biology. Cattle
Practice. 16, 122-126.
(3) Courtenay, O.,L.A. Reilly, F.P. Sweeney, V. Hibberd, S. Bryan, A.
Ul-Hassan, C. Newman, D.W. Macdonald, R. J. Delahay, G. J. Wilson and E.
M. H. Wellington. (2006). Is Mycobacterium bovis in the
environment important for the persistence of bovine tuberculosis? Biology
Letters 2: 460-462. Doi: 10.1098.rsbl.2006.0468
(4) Courtenay O, Reilly LA, Sweeney FP, Macdonald DW, Delahay RJ, Wilson
GJ, Cheeseman CL, Keeling MJ & Wellington EMH. (2007). Limitations of
targeted badger culling based on the detection of environmental Mycobacterium
bovis. Vet. Record 161, 817-818. Doi: 10.1136/vr.161.24.817
(5) Sweeney F. P., O. Courtenay, V. Hibberd, R.G. Hewinson, L.A. Reilly,
W.H. Gaze and E.M.H. Wellington (2007). Environmental monitoring of Mycobacterium
bovis in badger faeces and badger sett soil using real time PCR,
confirmed by immunoflourescence, immunocapture and cultivation. Appl
Environ Microbiol. 73, 7471-7473. Doi: 10.1128/AEM.00978-07
(6) Pontiroli, A., Travis, E. R., Sweeney, F. P., Porter, D., Gaze, W.
H., Mason, S., Hibberd, V., Woodbine, K., Holden, J., Moore, S.,
Courtenay, O., Wellington, E.M.H. (2011). Multi- operator DNA extraction
trials lead to improved quantitation of Mycobacterium bovis in the
environment. PLoS One 6 (3):e17916. Doi: 10.1371.journal.pone.0017916
(7) Travis ER, Gaze WH, Pontiroli A, Sweeney FP, Porter D, Mason S,
Keeling MJ, Jones RM, Sawyer J, Aranaz A, Rizaldos EC, Cork J, Delahay RJ,
Wilson GJ, Hewinson RG, Courtenay O, Wellington EM. (2011). An
inter-laboratory validation of a real time PCR assay to measure host
excretion of bacterial pathogens, particularly of Mycobacterium bovis.
PLoS One. 6(11):e27369. Epub 2011 Nov 14. Doi:
Peer-reviewed grants and awards All grants listed were awarded to
either Elizabeth Wellington and/or Orin Courtenay as PIs
• Tuberculosis epidemiology and novel transmission routes in rural
Tanzania. NIH International Collaborations in Infectious Disease Research
(ICIDR) U01. RFA-AI-09-010 (2010-2014), US$3 mln. Joint with University of
California, San Francisco; Sokoine University of Agriculture; Muhimbili
Medical Research Center, Tanzania. PI Wellington http://projectreporter.nih.gov/project_info_description.cfm?aid=7901697&icde=17402708
• Optimisation of sampling strategies for improving sensitivity of M.
bovis detection by PCR. DEFRA Bovine Tuberculosis RRD project SE3280
(2012-2014), £380k. Wellington (PI) with Courtenay (Co-I)
leted=2&ProjectID=18036 - Description
• Intra- and extra-cellular mechanisms affecting the persistence of Mycobacterium
bovis in the environment: towards molecular surveillance of bovine
TB. BBSRC BB/E020925/1 (2007-2011), £797k. Courtenay (PI) and Wellington
(Co-I), University of Warwick. http://www.bbsrc.ac.uk/pa/grants//AwardDetails.aspx?FundingReference=BB/E020925/1
• Validation and epidemiological application of molecular methods for
monitoring M. bovis survival and dissemination in the
environment. DEFRA SE 3231 (2007-2010), £1.3 mln. Wellington (PI)
and Courtenay (Co-I), University of Warwick.
ortOrder=ASC&Paging=10 - Description
• The Biology of Environmental Mycobacterium bovis, and its
significance to the epidemiology of bovine tuberculosis. BBSRC 10668
(2004-2007), £381k. Courtenay (PI) with Wellington (Co-I),
University of Warwick.
Details of the impact
a) Health and Welfare.
The Irish government provided exclusive access to samples to enable
analysis of the impact of oral vaccination on shedding in a natural
population of badgera. Data derived from sample analysis were
used to determine shedding and infectivity during the vaccine trial. This
established the efficacy of the oral vaccine, which could be suitable for
distribution in food bait.
The group has trained vets in Tanzania to use the methodology to test
shedding in cattle. A letterb from the Head of Vet School,
Sokoine University of Agriculture confirms that the assay is used to
monitor M. bovis load in wildlife in the National Parks of Ruaha
and Serengeti, and cattle in adjoining areas.
The current UK Governmentc will consider adopting this assay
in 2013 as it is unique in providing quantitative, highly specific and
sensitive analysis of infection loads (Secretary of State for Environment,
Food and Rural Affairs made two visits for detailed discussions and will
support its use).
The assay is in use for monitoring faecal shedding in wild boar and
cattle, and to detect environmental contamination.
b) Decisions by a regulatory authority have been informed by the
The assay is in use by VisaVet (European Centre for Veterinary Health, EU
Agency) to monitor bTB in wild boar and red deerd, and in
Tanzania by vets monitoring shedding in cattle herds on the border area
with the Ruaha wildlife parkb. Recently DEFRA held a workshop
at AHVLA (April 2013) and a group of scientists, including the team from
the University of Warwick, participated in a discussion to establish which
methods were most specific, sensitive and useful to detection of bTB in
wildlife. The molecular assay of the University of Warwick's team was
selected as the test of choice to detect shedding and to track
environmental contamination. This test will be used by Defra.
c) Public awareness of health risks or health benefits has been raised
Farming cooperatives such as the Conservative Rural Affairs Group in the
UKe contacted us as a result of media interest following Prof.
Wellington's BBC interviews during the past 4 years (latest BBC Midlands,
In terms of benefits to wildlife conservation, in addition to the work in
Tanzania, the assay has been used to monitor bTB in African buffalo (Syncerus
caffer) in South Africa in collaboration with the Mammal Research
Institute, University of Pretoria; Ezemvelo KZN Wildlife, Mtubatuba; and
the Faculty of Health Sciences, Stellenbosch University. The group in
Stellenbosch have an interest in monitoring human faeces, particularly in
neonates in Stellenbosch hospital. The bTB status of cattle and
environmental contamination is a major source of infection in Africa, as
raw milk is consumed and this can lead to TB transfer to humans if cattle
Public awareness of bTB infection in badgers in the UK is acute and the
group from the University of Warwick liaises with the UK Badger Trust to
demonstrate how the assay and the team's research are providing important
parameter values to improve mathematical models of disease transmission
and control. This is particularly relevant at present as culling is taking
place alongside vaccination in the UK.
d) Animal Health and welfare has been enhanced
The method benefits animal welfare, as the assay is non-invasive and
provides monitoring of disease status in wildlife without the need for
trapping, anaesthesia, or any kind of trauma that results from other
methods, all of which are invasive.
e) Impacts on public policy and services
- Policy debate has been stimulated and politicians have been made aware
of the importance of shedding in relation to infectivity and its control
by vaccination. Debate was stimulated in both the National Assembly in
Wales (14/02/2007) and English parliament (meetings with Secretary of
State for Agriculture 03/05/2006 and with Secretary of State for
Environment, Food and Rural Affairs 10/01/2013 and 18/07/2013) about the
use of the `Warwick test' to determine levels of environmental
contamination, the extent of faecal shedding and risks presented to
- There is possibility of new technology being adopted; for example,
through Government encouragement of UK farmers to take responsibility
for biosecurity. Discussions have focused on the implementation of
testing for environmental contamination at the farm scalec.
- The quality, accessibility, acceptability or cost-effectiveness of a
public service is likely to have improved. The assay provides the least
expensive method of monitoring bTB in badgers and will contribute to
effective bTB control in the future in combination with vaccination and
limited strategic culling. Cage trapping is about four times more
expensive than the PCR tests.
f) Impacts on practitioners and services
- Training of vets has been influenced by the research; the new
methodology has been taught to vets (5) in Tanzania and at the AHVLA in
the UK, and staff (4) at VisaVet in Spain. The assay represents an
improvement in disease monitoring as current practices for wild life
rely on time consuming and more expensive cage trapping, tranquilizing
and sampling blood for immune assays.
- Practitioners and professionals have used our research methodology in
conducting their work. For example monitoring shedding in African
Buffalo, which skin tested positive. Monitoring cattle and goats in
Tanzania to detect which herds have a hire prevalence of bTB, current
prevalence of shedding is 12% over 6 villages with a range of 24.6%.
Sources to corroborate the impact
a. Person who can be contacted: Veterinary Scientist, Senior Research
Associate, School of Veterinary Sciences, University College,
Dublin. Can provide confirmation of the utility of the assay for analysis
of the impact of vaccination on shedding by scientists involved in the
trial, following Republic of Ireland vaccine trial. (Identifier 1).
b. Letter of support: Professor of Veterinary Medicine,
(responsible for training vets in Tanzania, centre of excellence,
Department of Veterinary Medicine and Public Health at the Faculty of
Veterinary Medicine, Sokoine University of Agriculture (the letter
emphasises the importance of the technology for farmers, wildlife parks
and the health of pastoralists). The Professor is responsible for the
Veterinary Public Health Unit at the University. His main activities are
to teach, research and outreach activities in the field of Veterinary
Public Health, Epidemiology, veterinary laws and policies. (Identifier 2)
c. Person who can be contacted: Secretary of State for DEFRA. The
Secretary of state gave verbal confirmation of the importance of the
technology for controlling disease in badgers. (Identifier 3)
d. Letter of support: Director, VisaVet, Spain (the letter
confirms the current use of the group's technology). (Identifier 4).
e. Letter of support: Chairman, Conservative Rural Affairs
Group. Verifies the effective of Wellington's method of detecting
bovine tuberculosis, which is equal to that of the current skin test.
Confirms the benefits of the test over alternatives, in terms of cost and
animal welfare. (Identifier 5).