Bovine tuberculosis (bTB), caused by the bacterium Mycobacterium bovis (M. bovis), is an infectious disease of cattle which is found throughout the world. It can affect practically all mammals and can be naturally transmitted from animals to humans under certain conditions.
Lord Benyon, former Defra Minister, discusses the 25-year TB eradication strategy for England.
Lord Benyon, former Defra Minister, discusses Cattle vaccine development.
With a comprehensive bTB eradication strategy in place, and the widespread use of milk pasteurisation in the dairy industry, human cases of TB caused by M. bovis infection are now rare in the UK. However, bTB remains devastating for affected farmers and rural communities in England and currently costs taxpayers around £100 million every year.
There is no single measure that will provide a solution to eradicating this complex disease in both cattle and wildlife. That is why the government is working in partnership with industry to drive forward a wide range of evidence-led interventions to achieve the goal of bTB free status for England by 2038. Defra’s bTB eradication strategy is working. A sustained downward trajectory in disease is being seen in areas of England at highest risk of bTB. Government and industry must continue to work together to build on these gains.
Next steps for the strategy
The government’s response to Professor Sir Charles Godfray’s independent review of the bTB eradication strategy set out five priorities for completion by 2025.
Progress so far
Develop a deployable cattle TB vaccine, as part of a wider programme of bTB research
BCG, a vaccination against bTB, has been around a long time. However, the government has not been able to use it because the vaccine interacts with the current tests used to detect bTB infection and it is not an authorised veterinary medicine. Government scientists in the Animal & Plant Health Agency (APHA) made a major breakthrough in the development of a potential new “DIVA” skin test (to Detect Infected among Vaccinated Animals). This new test could overcome these testing challenges by identifying cattle that are infected with M. bovis despite having received the vaccine, i.e. true-positives.
In 2021, cattle TB vaccination field trials began in England and Wales using CattleBCG in combination with this potential new DIVA skin test. The aim of these trials is to gather information to support applications for UK marketing authorisations of both products and international recognition. Having a deployable TB vaccine for cattle (i.e. with UK marketing authorisations) depends on the success of these trials.
Evolve the strategy for preventing spread of TB from wildlife
Badger culling
Evidence suggests that badger culling has contributed to a decrease in TB incidence in cattle in England. The government is now moving from culling to wider scale badger vaccination as the primary TB control measure in badgers.
A phased transition away from badger culling will help protect gains already made and ensure continued incremental progress towards disease eradication. Targeted culling will remain an option where needed.
- Natural England will not be issuing any new Badger Disease Control (intensive cull) licences after December 2022
- New Badger Disease Control (intensive cull) licences issued in 2021 and 2022 could, after two years of culling, be revoked after a progress evaluation by the UK’s Chief Veterinary Officer (CVO)
- New Supplementary Badger Control (SBC) licences issued from 2021 are restricted to a maximum of two years
Badger vaccination
To help the transition towards widespread badger vaccination and build industry confidence in this control measure, Defra has bolstered APHA vaccinator capability to deploy badger vaccination over larger, more contiguous areas. Over time this will help gather more evidence of the direct impact of badger vaccination on the spread of TB to cattle.
- Government-funded badger vaccination is progressing in several areas where four-year intensive badger culling has ended. The government is preparing to carry out even more badger vaccination in post-cull areas from 2023.
- Defra is funding a five-year project in East Sussex to support the farming community to deliver badger vaccination over an area of 250km2. The project, which started in 2021 and is coordinated by a local veterinary practice, should provide a template for future large-scale badger vaccination schemes.
- Cage-trapping and vaccination training courses have been streamlined to make them less time-consuming and more accessible. A new Train the Trainer (TtT) scheme enables experienced cage-trappers and lay vaccinators to qualify as trainers and form their own local training hubs. This has increased the number of training providers, creating capacity to enable more people to be trained.
In June 2022, Defra launched a new simplified licence for vaccinating badgers, significantly reducing the administrative burden for those who are trained to undertake this activity. A new subsidy has been applied to the BadgerBCG vaccine which cuts the cost by almost half. Both initiatives will make it easier and less expensive for farmers, landowners, and other groups to get involved in badger vaccination schemes.
Improve diagnostics, surveillance and epidemiology
Defra continues to invest in research and development to enhance TB diagnostic, surveillance and epidemiological capability.
- APHA is using a polymerase chain reaction (PCR) test which can detect M. bovis directly from tissue samples collected at post-mortem inspection. This method reduces the time taken for APHA laboratories to report results to livestock keepers from up to 22 weeks to just three weeks. In certain TB incidents, if the PCR test results are negative and the required TB testing has been completed where applicable, herd movement restrictions can be lifted sooner.
- Whole genome sequencing (WGS) of M. bovis isolates has been rolled out across GB. This supports APHA field vets in their investigations into TB breakdowns to understand how the disease could have entered the herd and whether it could have spread.
- Defra has protocols in place for voluntary private use of interferon-gamma blood testing and novel non-Defra approved TB diagnostic tests for cattle in specific circumstances. Private testing allows farmers and their private vets to further supplement Defra’s statutory testing policy to facilitate resolution of TB breakdowns
- Defra continues to fund research to develop a new, improved skin test using molecularly defined (synthetic) tuberculin. This would overcome the limitations of traditional tuberculins that form the basis of the current skin test used to screen cattle for TB
- Defra has invested in the evaluation of TB serological tests for use in deer and pigs
- More frequent routine TB surveillance testing of cattle herds in the High Risk and Edge Areas of England was implemented in 2021
Encourage the farming sector to reduce the spread of bTB through increased uptake of effective biosecurity measures and enhancing the tools for informed purchasing
Defra is supporting farmers and landowners to improve on-farm biosecurity, while also ensuring that they have the information they need to reduce farm-level TB risk when trading cattle. A range of measures have been implemented to support this aim.
- Cattle Health Certification Standards (CHECS) bTB entry level membership and accreditation schemes facilitate adoption of biosecurity measures to reduce the risk of a TB breakdown.
- Information bTB (ibTB) is a free-to-access, online, interactive mapping tool displaying the location of historic and ongoing TB breakdowns in England and Wales over the last 10 years.
- The TB hub website launched in 2015 as a joint industry and government initiative. It is the ‘go-to’ place for British cattle farmers to find practical advice on both preventing and dealing with bTB on their farm.
- The TB Advisory Service (TBAS) in England provides free, bespoke advice to keepers of cattle and farmed non-bovine animals on bTB biosecurity measures.
The new Annual Health and Welfare Review is the first step farmers can take on the government’s Animal Health and Welfare Pathway. It will introduce a vet visit that farmers will receive on an annual basis. A farmer’s own vet, or vet-led team, will carry out diagnostic testing, collect data and provide bespoke advice on management to improve the health, welfare and biosecurity of their animals and the responsible use of medicines, including antibiotics.
Create a stronger partnership between government, industry and other key groups by improving cooperation at every level
Another recommendation from the Godfray review was to establish a new bTB Partnership for England between government and industry to encourage shared ownership, coordination and decision making on bTB eradication. The bTB Partnership was formed in 2021 and encompasses a wide range of farming, industry, veterinary, academia and wildlife expertise.
Other work
Support for the farming community
The government is acutely aware of the devastating personal impact of bTB on livestock owners and their families. Defra is working hard to support farmers whose herds experience a TB breakdown and ensure that information and support is readily available.
Defra is committed to helping farmers and their families tackle the mental health and livelihood impacts of bTB and has provided grant funding to the Farming Community Network (FCN) since 2010. More recently, Defra provided FCN with a separate grant to help improve their resilience to events like the COVID-19 pandemic, in recognition of the valuable support it offers to farmers.
