BOVINE TB ERADICATION STRATEGY - Strengthening the eradication programme and new ways of working

Members of the Animal Welfare Group attended the workshop session held by DEFRA in Telford on 2 October. In preparing their response they have taken into account the discussion in Telford and the issues raised in Government publications. They have also sought to consider other matters which they consider should be investigated and evaluated in devising a control strategy to deal with bovine TB.

The response comprises 3 sections:
1 The role of vaccination, with regard to both cattle and badger populations
2 What risk factors contribute to the dissemination and transmission of disease and how these can be mitigated
3 How the Government, the industry and other agencies could work together to enable a united and co-ordinated integrated strategy for, and implementation of, bovine TB eradication measures.

BOVINE TB ERADICATION STRATEGY Strengthening the eradication programme and new ways of working
1 VACCINATION
1.1 Cattle vaccination
1.2 Badger vaccination


2 WHAT RISK FACTORS CONTRIBUTE TO THE DISSEMINATION AND TRANSMISSION OF DISEASE - and how can these be mitigated
2.1 Implementing recommendations of external audit of control procedures
2.2 Detection of disease – are the current surveillance tools appropriate
2.3 Increasing immunity & decreasing susceptibility to infections and disease - the role of diet and nutrition
2.4 Role of Liverfluke
2.5 Persistence of M Bovis Bacterium in the environment
2.6 Addressing the infection in wildlife
2.7 Insufficient epidemiological investigation


3 WORKING TOGETHER
How the Government, the industry and other agencies could work together to enable a united and co-ordinated integrated strategy for, and implementation of, Bovine TB eradication measures
3.1 Risk Assessment
3.2 Introduction of additional control measures
3.3 With regard to the issues relating to controlling disease in the badger population.


4 Conclusions RESPONSE We set out below our response to your call for views on improving and exploring what means and methods should be utilised in eradicating bovine TB

1 VACCINATION
1.1 Cattle Vaccination
We fully support the commitment by Defra to develop both a suitable cattle vaccine and an appropriate DIVA test to distinguish between response to infection as opposed to response to vaccination.

Quite rightly this project, and its funding, is the main Research and Development activity underway to combat the spread of bTB.

With reference to the Defra information on this: http://www.defra.gov.uk/animal-diseases/a-z/bovine-tb/vaccination/cattle-vaccination and additional reports from Prof Hewinson and the VLA team working on the project we understand that discussions are on-going with the Veterinary Medicines Directorate, re the vaccine and associated DIVA test. The use of vaccination, applied in conjunction with the DIVA test, would enable protection of livestock from disease while not compromising the eradication programme. While vaccination may not need to be applied across the whole of England it could be used to reduce the level of infection in areas of concentrated disease. With the appropriate protocol the process could be applied either on a regional or zoned basis, or as a firewall to prevent further spread to adjacent areas.

In addition, given the global perspective and incidence of bovine TB, and the desire of other countries to utilise vaccination, we fully support the commitment of the UK Government to pursue this and the leading role being undertaken by UK scientists to advance this approach.

Recommend : That the project is pursued with all urgency and that discussions are progressed swiftly, and concurrently, with the following organisations and bodies:
I The EU to determine what will be required to enable England, to use the vaccine and DIVA test and what derogations from the EU Bovine TB Directive can be put in place to achieve this.
2 The Livestock Industry and the NFU to identify and deal with issues relating to trade in vaccinated animals and products, and what other concerns the industry has in utilising a vaccination protocol.
3 The OIE to gain appropriate changes to the Animal Health code to enable utilisation and to determine how the use of vaccination and DIVA will affect any disease free status classifications and how these can be overcome.
4 Those involved with the export of livestock, meat and other animals products to determine what trade is likely to be affected and how this can be dealt with.

Reason: It is important that the introduction of cattle vaccination and the DIVA test is not delayed by discussions and negotiations regarding the EU, trade or animal health rules once the EU Veterinary Medicines Directorate has approved both the vaccine and the DIVA test for use.
1.2 Badger Vaccination
We cannot, for ethical and humane reasons, totally eradicate the badger population and therefore must find a way of enabling badger populations to remain in existence without compromising the viability of the livestock and dairy industry.
It is therefore regrettable that only one of the badger vaccine field trials is now proceeding, as opposed to the six that were originally due to be undertaken. Scientific studies in the field could have provided important data to help evaluate the efficacy of vaccinating badgers and how this then impacts on the incidence of new cases of bTB in the area.
However as vaccination should reduce the prevalence of disease in the badger population it is important that wherever possible farmers and the local badger trusts work together to enable vaccination of badgers wherever possible. Badger trusts and local badger group personnel are being licensed by Natural England to undertake the vaccination.
While these measures are available it is noted that trapping and vaccinating badgers requires licensed lay vaccinators, and for the badgers to be trapped and vaccinated by injection.
Therefore a means of delivering the vaccine orally would be less labour intensive and would not require so much skilled time and equipment.
We understand that an oral vaccine suitable for deployment has already been developed in New Zealand for use in controlling the non-native possum population. Until the UK has developed and had an equivalent formulation approved we suggest that consideration be given to applying to the EU for a license to use the NZ product, until the UK version is available.

Recommend:
1 That farmers are encouraged to engage with their local wildlife trusts and badger groups to work together to vaccinate the badger population on their land to protect badgers from disease and to reduce the prevalence of disease and transmission of disease to livestock
2 That priority is given to bringing forward the licensing and use of an oral badger vaccine in conjunction with New Zealand Agricultural Department – which has also developed a suitable oral vaccine – and which appears to be closer to utilisation than the one currently under development in the UK.
Reason: The European badger is a native indigenous species in the UK and for ethical and humane reasons it cannot be culled into non-existance. We need to enable the badger population to co-exist with the livestock industry without the risk of transmission of disease.

2 WHAT RISK FACTORS CONTRIBUTE TO THE DISSEMINATION AND TRANSMISSION OF DISEASE - and how can these be mitigated against

2.1 IMPLEMENTING RECOMMENDATIIONS OF EXTERNAL AUDIT OF CONTROL PROCEDURES The reports of the two visits of the SANCO committee following their visits in September 2011 and March 2012 both contain extensive recommendations regarding improvement in the TB eradication procedures in the UK. DG(SANCO) 2011-6057 - MR FINAL

FINAL REPORT OF AN AUDIT CARRIED OUT IN THE UNITED KINGDOM FROM 05 TO 16 SEPTEMBER 2011 IN ORDER TO EVALUATE THE OPERATION OF THE BOVINE TUBERCULOSIS ERADICATION PROGRAMME http://ec.europa.eu/food/fvo/act_getPDF.cfm?PDF_ID=9444
SANCO/2012/11191

REPORT OF THE "BOVINE TUBERCULOSIS" SUB-GROUP Meeting held in The United Kingdom 27-28 March 2012

http://ec.europa.eu/food/animal/diseases/docs/tb_subgroup_uk_2012_en.pdf

We have had regard to these findings and welcome and endorse the recommendations expressed. They articulate many of our own concerns relating to effective epidemiological investigations and ensuring an extensive range of disease control mechanisms are fit for purpose, properly implemented and adequately monitored.

No doubt regard will be had to the many issues raised by the recommendations in the reports, and we trust that Defra and AHVLA will address these, with urgency, and move swiftly to implement the necessary measures.

We would be grateful to be informed what measures Defra and the AHVLA intend to put in place in response to the findings of the SANCO inspections.

Recommendations

That Defra and AHVLA act swiftly to implement changes to incorporate the recommendations of the SANCO reports.

Reason

There are significant shortcomings in the current control mechanisms and these need to be rectified with urgency to enable bovine TB eradication.

2.2 DETECTION OF DISEASE – are the current surveillance tools appropriate. In Defra’s booklet ‘Dealing with Bovine TB in your herd’ – May 2008, it states that:“ the comparative tuberculin test can be expected to detect approximately 80% of all the infected cattle in a herd at any one test. This is known as the test’s sensitivity” In many countries this test is used as a herd test, whereby when disease is detected the whole herd is de-populated. However this is not the case in the UK, where only the reactors are eliminated, and inconclusive reactors removed after two inconclusive tests. There is therefore the likelihood that at any given time the test may fail to detect, on average, 1 in 5 of infected animals. This equates to not identifying 20% of infected animals in a herd.

There is considerable risk of further transmission from these unidentified infected animals, the implications of which, thus far, does not appear to have been factored into the disease control protocol. The problem of whether certain animals have become infected and yet do not respond to the intra-dermal skin test may be due to several factors; parasitic burden, malnutrition, secondary infections, zinc deficiency, stress or other causes. Furthermore there is the issue of whether testing frequency is sufficient to detect emerging disease in a herd after 2 tests at 60 day intervals, and then no further tests being carried out, and a return to the normal testing interval. The factors outlined above can then lead to further dissemination of disease within the animals in the herd.

The undetected infection can then remain circulating in the herd, in close contact with other animals when housed, in parlours, at feeders. water troughs and general inter-mingling. In addition such animals will be excreting infection into the environment whether housed or at pasture and being passed on in water or feeders, via contaminated ground, or close contact with other animals.Also, the intermingling of cattle at markets and shows, after two 60 day intervals of clear tests, may also be allowing undetected disease to circulate further.

Another factor which may be contributing to dissemination of disease is the increase in movements of cattle during their lifetime to finishing units or for other stock management reasons, enabling further contact with animals that may not have been reactors but which are still harbouring disease. A further major consideration is whether the tests are frequent enough, in areas outside the ‘hotspots’ to detect emerging disease. The problem of under detection is then further confounded by the current testing intervals, where in some areas the testing interval is greater than once a year. Where testing is on a 2, 3 or 4 year testing interval this allows a considerable amount of time to elapse for the disease to go undetected and be spread through a herd, or disseminated at markets, or shows or through movements to different holdings. It is worth noting that:

“In the 1920s a control strategy was initiated which included cattle testing and slaughter of infected cattle combined with the following regulations:
1) Double fencing of attested farms to ensure adequate isolation from nontested Cattle
2) Movement of attested cattle to shows or sales governed by movement permits issued by local Veterinary Officer of the Ministry of Agriculture.
3) Only attested cattle introduced directly into attested herds without being isolated (if from attested herds they had to be retested after isolation for not less than 60 days) (Fishwick, 1952).
This strategy led to a reduction in prevalence of the disease to less than 0.05% of total herds in England and Wales in the late 1970s.”
Source: MAFF Publication
The role of cattle husbandry in the development of a sustainable policy to control M. bovis infection in cattle Page 7.

Given the uncertain nature of the intra-dermal skin test, and for the outcome to be affected by several other factors, as outlined above, it needs to be questioned whether the free movement of cattle between holdings, to markets and to shows, needs to be the subject of more pre-movement testing closer to the time of movement.

There may also be the need to find ways in which the intermingling between holdings and by trade and shows can be minimised.

The decreased frequency of testing, especially in areas of 2, 3 or 4 yearly intervals should be a significant area of concern.

At present there appears to be insufficient recognition of the role of undetected infected cattle in disseminating disease, and how this should be addressed..

Recommendation:
That further consideration should be given to the role of undetected infected cattle and control measures to be put in place to deal with the likelihood that such carriers are likely to be present. In relation to:
• On farm hygiene and bio security both in housed and pasture situations
• Transportation and attendance at market
• Transportation and attendance at agricultural shows
• What amendments to the testing regime could increase detection of disease and reduce the likelihood of undetected reactors passing on infection
• The frequency of testing should be reviewed to assess whether this addresses the risk posed by the disease remaining undetected for significant periods of time, and even several years.

Reason
The intra-dermal skin test may be detecting only 80% of cases present in a herd at any one time. Measures need to be put in place to address the likelihood that there is residual, unidentified infection present and the risk of this disease being passed on and it is crucial that the risk should be identified and minimised.

2 .3 INCREASING IMMUNITY & DECREASING SUSECPTIBILITY TO INFECTION AND DISEASE – the role of diet and nutrition.
Several factors affect the immunity and susceptibility of both cattle and badgers to infection. The role of diet and nutrition, including the presence, or absence, of trace elements, stressing, housing, transportation and selective breeding may all be worthwhile considerations.

Clearly good animal husbandry should ensure that cattle health is maximised to maintain yields and productive stock. However the increasing use of maize based silage and other foodstuffs with depleted mineral content requires further consideration. In particular the role of trace elements has not been fully evaluated in scientific trials but studies undertaken by farmers and soil scientists in the field would indicate their presence is crucial in conferring immunity and decreasing susceptibility.

In particular the farm trials carried out by Mr Dick Roper in Northleach, Gloucestershire and the many farms treated by Mr Goodwin Jones of Trace Elements Services Ltd illustrate that there are significant benefits of improved immunity from the inclusion of trace elements in the diet of cattle and also badgers. We have details of these trials and can provide further information if required.

Defra and the VLA have already undertaken some research in this area:
http://randd.defra.gov.uk/Document.aspx?Document=SE3013_5852_FRP.doc
Pathogenesis and diagnosis of tuberculosis in cattle - complementary field studies. SE3103
- This relates to field studies carried out between 2000 and 2005

Results - extract
Levels of the enzyme GSPHx, a surrogate for plasma selenium, were lower in in-contacts than in reactors and lower in animals with confirmed bTB than in animals without confirmed bTB. In a logistic regression model adjusting for confounders, animals in the lowest two quintiles for selenium exposure (levels below 65 u/mL RBC) had an almost three fold higher risk of having confirmed bTB aOR 2.85 (95%CI 1.21-6.71). There was also an association between low in liver selenium and increased risk of bTB confirmation although it was not statistically significant (0.95 per μmol/kg DM (95%CI 0.9-1.0)).

Implications - extract Consistent negative associations between low levels of GSPHx in blood and selenium in liver and a higher risk of an animal being infected with M. bovis require further investigation; particularly to establish whether the effect is causal or a consequence of disease. The lower risk of confirmed bTB related to previous exposure to liver fluke also requires further investigation.

The EFRA Select Committee also considered the role of trace elements.
http://www.publications.parliament.uk/pa/cm200304/cmselect/cmenvfru/638/63805.htm#a11

Extracts:
Trace elements
36. The argument is advanced by some that dairy cattle in particular lack certain key trace elements in their diets, and thus are more susceptible to bovine TB. In her evidence Dr Helen Fullerton told us that trace element deficiencies induce a susceptibility to M.bovis, and also give rise to 'false negatives' in the TB skin test.[59] The trace elements in question are zinc, selenium, cobalt, copper and iodine. She attributed deficiencies to their "relentless extraction from the soil by intensive cropping", and also says that TB 'hot spots' tend to be located in areas with rock types - limestone and chalk, red sandstone and granite - which are "instrinsically low" in trace elements.[60]

37. The view of the farming community is mixed. One farmer told us that trace elements are "yet another 'red herring' thrown up by National Federation of Badger Groups et al … another myth [which ought to be] laid to rest".[61] Indeed it was argued that dairy farmers obviously feed their cattle well, since they require high yields. But the National Farmers' Union accepted that "there are still a number of questions unanswered in relation to susceptibility and resistance … Resistance to infection may indeed be related in particular cases to levels of trace elements such as selenium - and there are those who suggest that it is - and attempts should be made to establish the significance of this one way or another".[62]

38. The Chair of the ISG told us that the Group had already looked closely at the issue of trace elements, and had reported to Ministers.[63] It said that in his evidence Professor Bourne said that on the basis of experimentation there is no evidence that there is absolute resistance [as a result of trace elements]. There may be degrees of resistance but the factors influencing that are so variable as to make it extremely difficult to pursue experimentally … I would advise you to look at the detailed comment we made about this experimental approach which does indicate very clearly that to do this experimentally is virtually impossible. It would [also] be extremely expensive.[64]

39. Although the Minister acknowledged the point made by Professor Bourne about the difficulty of conducting experiments in this area, he told us that the results of the TB99 survey might yield "some non-scientific but useful indication on breeds, on feed, on geography and geology that we were not hitherto aware of".[65] We agree with the Minister. Although we do not believe that trace elements should become a main focus of research activity, they are clearly an area of interest. We therefore recommend that Defra consider ways in which it might encourage projects aiming to find out more about trace elements.

With regard to Professor Bourne’s comments we have looked at all the ISG reports, including the 3rd report which is cited in the EFRA Select Cttee report as link (63) see above. We could find no mention in any of the reports dealing with trace elements. It would be helpful to know in what context the ISG considered the role of trace elements and on what basis the views put forward by Prof Bourne, in giving evidence to the EFRA Select Committee, were made.

Further work on the subject was also described in the paper by:
Downs, S.H., et al., Trace micro-nutrients may affect susceptibility to bovine tuberculosis in cattle, Prev. Vet. Med. (2008), doi:10.1016/j.prevetmed.2008.05.003

Both the scientific papers stated that further work was needed on the subject, as did the EFRA Select Committee.

Also, given that the incidence of disease has seen some correlation with the increase in use of maize as a fodder crop, and that maize is known to be inherently low in trace elements it would appear that this should be investigated. In addition badgers also have a predilection for the crop and again may also be more susceptible to disease as a result.

In particular, we submit that the crucial roles of iodine, selenium, copper, zinc and cobalt should be fully investigated in relation to the immune system of both cattle and wildlife hosts, especially badgers. With reference to this we submit a paper presented by Dr Helen Fullerton to the Royal Society. We believe it is timely to look again at the case that Dr Fullerton advanced re the role of trace elements and the incidence of bovine TB.

See paper. ‘Bovine Tuberculosis: A Nutritional Solution’ Despite several attempts and recommendations to include these factors in determining the control mechanisms for bovine TB nothing has been taken forward. Such measures do not require any agreement from the EU, they do not need to be licensed and could be implemented by farmers immediately. In any event the information provided by Dr Fullerton requires a much wider dissemination to enable livestock owners to have regard to the arguments she puts forward. In the interests of the health of their livestock, and the ability of their stock to resist infection, many farmers may welcome the opportunity to enhance this by relatively economic means.

Furthermore the inclusion of trace elements as an important part of livestock health does not need to wait to have fully validated, peer reviewed, scientific investigation, but could be rolled out in advisory literature, on the basis that optimal levels of trace elements in cattle nutrition confers a wide variety of benefits. Not least amongst these is that it may well go some way to significantly increasing immunity and decreasing susceptibility of stock to bovine TB infection.

Recommend:
1 That livestock owners, and their organisations, are made aware of the need to maintain the ultimate health of livestock as a means of increasing immunity and decreasing susceptibility to infection and disease.
2 That diet and nutrition have a very important part in maintaining ultimate health and that pasture, silage and other feedstuffs should contain the optimal levels of trace elements to support and maintain the immune system.
3 That further work be undertaken to understand the role of trace elements in this process. It may be possible for this to have regard to parallel studies that have been conducted in relation to human nutrition and the immune response.

Reason:
To increase the health and immunity of the national herd to challenge by infection and to reduce the susceptibility to the disease and further transmission

2.4 ROLE OF LIVERFLUKE PARASITE
As referred to above, the presence of some parasites may also be influencing the sensitivity of the intra-dermal test and the failure to detect bTB in cattle.

A recent study published in Nature Communications, May 2012, suggests that there may be an under-ascertainment rate of about one third, and that this may in part explain the continuing spread of TB and the failure of the current eradication programme to control the disease. Enclosed below is an extract from the paper and the link.
http://www.nature.com/ncomms/journal/v3/n5/full/ncomms1840.html
Fasciola hepatica is associated with the failure to detect bovine tuberculosis in dairy cattle Jen Claridge1, Peter Diggle1,2, Catherine M. McCann1,†, Grace Mulcahy3, Rob Flynn3,†, Jim McNair4, Sam Strain4, Michael Welsh4, Matthew Baylis1,* & Diana J.L. Williams1,*

Bovine tuberculosis (BTB) is a significant and intractable disease of cattle caused by Mycobacterium bovis. In the United Kingdom, despite an aggressive eradication programme, the prevalence of BTB is increasing with an unexplained, exponential rise in cases year on year. Here we show in a study involving 3,026 dairy herds in England and Wales that there is a significant negative association between exposure to the common, ubiquitous helminth parasite, Fasciola hepatica and diagnosis of BTB. The magnitude of the single intradermal comparative cervical tuberculin test used to diagnose BTB is reduced in cattle experimentally co-infected with M. bovis and F. hepatica. We estimate an under-ascertainment rate of about one-third (95% confidence interval 27–38%) among our study farms, in the hypothetical situation of no exposure to F. hepatica. This finding may in part explain the continuing spread of BTB and the failure of the current eradication programme in the United Kingdom.

DOI: 10.1038/ncomms1840
Received 18 Jan 2012 | Accepted 11 Apr 2012 | Published 22 May 2012
1 Institute of Infection and Global Health and School of Veterinary Science, University of Liverpool, Liverpool L69 7ZJ, UK. 2 Lancaster Medical School, University of Lancaster, Lancaster LA1 4YB, UK. 3 School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. 4 Bacteriology Department, Agri-Food and Biosciences Institute, Veterinary Sciences Division, Stormont, Belfast BT4 3SD, UK. *These authors contributed equally to this work. †Present addresses: Division of Agriculture, Sir Arthur Lewis Community College, Morne Fortune, Castries, St Lucia, West Indies (C.M.M.); School of Veterinary Medicine and Science, University of Nottingham, LE12 5RD, UK (R.F.). Correspondence and requests for materials should be addressed to D.J.L.W. (email: williadj@liv.ac.uk).

Recommendations: 1 That further investigations are undertaken in relation to the role of llverfluke and its role in under-detection of the presence of bTB infection.
2 That in the interim, as a matter of good animal husbandry, and to optimise the health and welfare of cattle, both in the dairy and beef industry, that consideration is given to incorporating a fluke treatment protocol in conjunction with the testing programme for bTB. So that at the time of testing, using the intra-dermal test, there can be no masking of disease by the presence of the fluke parasite.

Reason: It is necessary to screen out any factors which may be influencing the under detection of bTB infection. In addition the role of good animal husbandry and welfare, by reducing parasitic burden, will also contribute to the ability of cattle to resist infection and disease.

Update: On 19 October we received a communication from Defra on this stating that, in its view, the study did not show any correlation between liverfluke and reduced detection of disease. We are contacting the authors of the paper to discuss this and will submit their response as soon as we have it.

2.5 PERSISTENCE OF M BOVIS BACTERIUM IN THE ENVIRONMENT

If it is agreed that the intra-dermal test is not detecting circa 20% of the incidences of infection, it then follows that those animals thus infected and not detected may be emitting and excreting the bacterium into the environment. This may not be on a constant basis, but when stressed or affected by other adverse factors. As referred to earlier these include poor diet or lack of nutrients, parasitic challenge, bullying at feeders, stress due to transportation, etc

Therefore both in housed and pasture situations there is a likelihood that the bacterium can be excreted into the surrounding environment. In the right conditions of high moisture and lack of exposure to sunlight the bacterium can survive for significant periods of time, either in shared feeders, water troughs, soiled bedding through urine and faeces, wet pasture or soils.

As a precautionary principle it is important to assume that there is a likelihood of latent infection in the herd and the necessary measures need to be taken to ensure that the opportunity for this infection to be passed on is minimised.

Bio-security is therefore important not only between specie – but also in the close confinement of housed animals, and in shared troughs, feeders, etc and in pasture in the field. In addition any animal housing needs to be subject to the appropriate and regular cleansing and disinfection to eliminate excreted bacterium. Likewise any vehicles used for transportation both on and off farm, to markets, shows and moving stock between holdings, etc also needs to be cleansed and disinfected, on a regular basis and especially when it has been in contact with other livestock and carriers. It may be worth considering whether the levels of cleansing and disinfection which were introduced and maintained during the FMD outbreak in 2001 need to be re-implemented to reduce the persistence of the bTB bacterium in the environments that cattle are in contact with.

Recommendations:
1 That more information and guidance is provided to livestock owners as to the likelihood of undetected infection within herds, at any time, and the need to safeguard against this being dispersed.
2 Providing advice as to what measures are appropriate to address this regarding herd health and hygiene, clearing of slurry, keeping food and water supplies clean, removing soiled bedding, dung etc.
3 Ensuring slurry is properly treated before spreading, and that it is spread on fields not used by cattle. 4 Ensuring strict cleansing and disinfection regimes on farm and in relation to all cattle transportation.


Reason
To limit the amount of disease circulating in the both the housed and pasture environment and in regard to any cattle movements, to ensure that cattle have limited opportunity to be exposed to the bacterium which persists in the environment.

2.6 ADDRESSING THE INFECTION IN WILDLIFE
While badgers are the most cited reservoir of bTB infection it is important to note that other hosts such as wild boar, rats and deer can also carry disease. The extent of infection in badgers across the UK is not fully known, and probably varies from district to district. Similarly it is not clear to what degree the badgers are infected in any given area. It is indeed unfortunate that the proposed badger cull will not test the culled badgers for the presence, or absence, of infection. Communication from Natural England has confirmed this. If such tests had been carried out this would have at least provided some data as to what percentage of the badgers culled were infected . Notwithstanding that the free shooting cull method will make it difficult to determine which setts the badgers came from, and not be accurate as to what percentage of the population has been culled. In addressing the as yet unquantified and unqualified level of infection in the badger population we support the role of vaccination in diminishing the amount of infection which may be occurring in the population. Also with regard to this we support the efforts of Defra in enabling individual farmers, landowners and organisations, such as the Badger Trust, National Trust and others to deliver an injectable form of bTB vaccine. We also support the research and development invested in producing, licensing and implementing the use of an oral form of vaccine for badgers. – see earlier comments.

In conjunction with this approach we submit that other means of reducing infection within the wildlife population need to be considered. It appears from several studies that badgers may also be suffering from nutrient deficiencies which render them also susceptible to infection. It is widely acknowledged that they are attracted to maize and maize silage, which is inherently low in certain minerals, such as iodine and selenium. The analysis of badger hair samples undertaken in 1987 by the NRM laboratory at Bracknell showed a range between 0.01 – 0.09 ppm of selenium, with a mean of 0.039. However the average badger body weight indicates the selenium level in hair should be at least 0.15ppm.

These figures, and other data, were supplied by Trace Element Services Ltd. of Camarthen, Wales The study also compared the results with those from other mammals such as cattle, sheep, swine and humans. By comparison it appears that badgers have virtually no selenium and approximately 12 times less than other measureable mammals. 0.5ppm being considered the lowest limit for normal function.

Trace Element Services have all the original results and this can be provided if required. Similarly an exercise undertaken by Dick Roper on the Will’s Estate at Northleach in Gloucestershire appears to indicate that there is a correlation between the incidence of bTB and selenium and iodine. The 3,000 acre farm is organic and the livestock includes 500-600 pedigree Angus cattle. Roper.found that by feeding the cattle iodine and selenium to overcome the deficiencies in maize silage and by supplying the badgers on his land with selenium and iodine enriched molasses twice a year he has remained bTB free despite neighbouring farms going down with the disease. While acknowledging this is work has not been carried out as part of a controlled experiment or peer reviewed, it still bears out the case advanced by Dr Fullerton in the paper already referred to. Also it is not illogical to consider that given the badgers’ predilection for maize and maize silage, it too becomes more susceptible to bTB infection if the concentration of iodine and selenium in its body falls too low. Outwith the cull areas it is still illegal to cull badgers, and therefore means must be introduced which not only limit the interaction of cattle with this potential source of infection, but also are directed at keeping the badger population free of disease.

There is already a substantial amount of advice on the Defra web site, in pamphlets and videos as to how the farm and farmers can minimise the contact between badgers and cattle, both in housed and pasture situations. However the issue of ensuring that the badgers themselves are kept free of infection has not been addressed. The action taken by Dick Roper should not be lightly dismissed. It was not a complicated procedure. It involved twice yearly placing a bucket of pre-mixed molasses, iodine and selenium supplement by each of the badger setts on his farmed land. Not only did this enable the badgers to intake the required trace elements to boost their immunity, but it also deterred them from using the mineral licks placed in the fields for the cattle to use.

Appended to this submission is a fuller account of his process. While appreciating that this is not a scientific study it appears that there is a significant correlation between the improved immunity of the resident badger population and, in turn the diminished incidence of disease, which significantly reduces or removes the possibility of the badgers then passing on the infection to cattle.

Recommendation:
1 That studies be undertaken to ascertain the levels of selenium and iodine within the badger population and to establish whether there is any correlation with the incidence of disease in the badger population.
2 That in the interim there is promotion of discussion with the industry as to ways in which infection in the wildlife reservoir can be minimised, and immunity conferred to wildlife populations, including the pro-active approach of improving the resiliance of the wildlife host to infection.

Reason
Badgers are a protected species and part of the wildlife ecology. If they are to co-exist with livestock it is better that they are resistant to disease and can withstand challenge of infection ensuring that they are then less likely to pass on infection to beef and dairy cattle.

2.7 INSUFFICENT EPIDEMIOLOGICAL INVESTIGATION
Although epidemiological investigation is undertaken after the occurrence of a new TB case we question if this is thorough enough to accurately determine the route of infection. Furthermore, does the investigation go far enough to trace back and remove the further risk of similar dissemination of disease from the initial source. From the various testaments we have heard; from farmers attending the Telford workshop, from press reports and personal communications it appears that there is insufficient investigation to determine how the infection has come onto, or into, the farm, where it has come from, when the infection was likely to have commenced and how long it has gone undetected .

The apparent lack of adequate epidemiological investigation therefore makes it very difficult to ascertain, in a meaningful way, what has given rise to the presence of disease. Far too often it seems that the most convenient answer is ‘ It came from the badgers’, but that is too simplistic and in any event it is not clear whether the identified host is, in the first place, are infected.

Such investigation requires consideration of local factors and the relationship to local, district and regional incidence of disease and trends. Regard needs to be had as to the activities on the farm, what movements have pre-ceeded the outbreak, what levels of bio-security and cleanliness are maintained, and how these inter-relate with the broader picture, and the consideration of trading movements and other transportations to shows, etc, and which animals have been moved onto the holding, or between holdings.

In addition it is necessary to be clear what movements of stock onto the farm have occurred over a considerable period as the disease may have gone undetected for some significant time. Information is therefore likely to be needed from the livestock owner, his local vet, and AHVLA vets, so a complete picture can be built up to explore all likely routes of infection and what other holdings and premises have been involved.

If insufficient epidemiological investigation is undertaken it will be (and has been) extremely difficult to be pro-active in dealing with the disease.

Recommendations:
That epidemiological investigations are improved to more accurately trace back new incidences of disease and identify the source of infection, and evaluate what length of time may have elapsed since the infection was introduced into the herd.

Reasons:
Much swifter action is needed to identify the likely source of infection and how long it has been on the farm/holding before detection and to allow the tracing back of the route of infection to remove infected stock from the source, and to trace any further routes of dissemination from this source..

3 WORKING TOGETHER
How the Government, the industry and other agencies could work together to enable a united and co-ordinated integrated strategy for, and implementation of, Bovine TB eradication measures

3.1 Risk Assessment
The main process of disease control has been predicated on identifying and removing infected livestock. Although pre-movement testing reduces somewhat the possibility of buying in infected animals, the limitations of the testing process – as described earlier, does not exclude the significant risk that brought in stock is infected. This process does not make it possible to get ahead of the disease and to be pro-active in ensuring that further herds and cattle are not exposed to infection, or if they are, that they have greater resistance to it. Similarly the implementation of disease prevention methods, bio-security and on farm hygiene needs to be independently overseen to ensure measures are put in place, and then maintained, to reduce incursions of disease.

What is needed is a collaborative approach with the farmer and his vet working together to draw up a protocol to maximise bio-security, farm cleanliness and hygiene, and to ensure that the health and welfare of stock is maintained via diet and nutrition and treatment for other infections and parasites. Such a protocol could be based on a nationally agreed set of criteria, which could be modified and adapted with the local vet to provide a bespoke model for that particular unit. The bespoke protocol could then be approved on an annual basis with the district/regional AHVLA, which at the same time could modify the protocol to take account of the district or regional circumstances.

This then needs to feed into a wider consultation with AHVLA to determine and quantify the risks of importing disease from trade and brought in stock, and to assess the risks of other movements on and off the holding, and between holdings.

Fundamentally what is required is a Risk Assessment for each farm and holding to determine, qualify and quantify the risks of exposure to bTB infection. Such an assessment would need to identify, from what source infection may arise and what procedures and methods needed to be put in place to reduce the risk both within the farm/land holding, between other holdings, from movements on and off the farm/holding and from the buying in of stock.

The Risk Assessment would also need to ensure that when reactors and inconclusives are identified that the right procedures and provisions are in place for these animals to be properly isolated until they can be removed from the holding. Similarly the protocol should also determine what quarantine facilities are available to isolate new stock until it can be established that they are not carrying infection.

Recommendation
Risk Assessments are put in place for farms and holdings, with livestock owners liasing with their local vet to identify risks of infection arising on the farm and between stock, via bio-security protocols, hygiene, cleansing, dis-infection, cattle health and nutrition, and in collaboration with district and regional AHVLA to determine how new stock is sourced to ensure infected animals are not bought on to the holding. The Risk Assessment to follow a nationally agreed format, which also allows for bespoke requirements for individual farms or holdings.

Reason To minimise the risk of disease transmission between animals on the holding, between holdings or from the buying in of new stock.

3.2 Introduction of additional control measures
In order to deliver a TB eradication strategy joint working between the livestock industry, government and other agencies is vital to the success of any policy. The introduction of more stringent cattle movement controls, a more rigorous testing programme, etc will undoubtedly impact on the day to day operation of the farm or holding and have implications for the viability of the business.

For such measures to be introduced it is important that there is an understanding as to why such measures are necessary, and that it is in the livestock owners’ interest to implement them.

For example, if it is clearly understood that the testing procedure may not be picking up all the infection present, and that there is a likelihood that despite a clear test there may well be residual infection present, then it is more likely there will be an acceptance that procedures and practices on the farm must be to operate with maximum bio-security. Furthermore, that more testing will then detect disease before it can be spread further.

Thus far it does not seem apparent that most livestock owners are aware of the limitations of the testing procedure, and that an all clear does not necessarily mean that there is no infection present in the herd. There needs to be common agreement that the most effective way of dealing with disease is predicated on the prevention of disease in cattle, in wildlife and in the environment and for there to be collaboration between the different organisations,

In such circumstances it is also important for information to be made available as to how the livestock owner can. on his own initiative. seek ways of reducing introduction of disease and also boost the immunity of his stock, and possibly susceptible wildlife on the farm.

The role of jointly agreed Risk Assessments, as outlined above, for the farm or holding could go some way in identifying all the factors that feed into this process and what can be done to minimise the risk of disease incursion.

Recommendation
When introducing new controls and regulations which may impact adversely on the viable operation of the farm or livestock unit it is important to explain why such measures are necessary and what benefit is to be gained by the imposition of these measures.That advice is given to farmers and livestock owners of the activities they can undertake to ensure that there animals are not exposed to disease, and how the immunity of stock can be improved.

Reason
Compliance with rules and regulations is crucial if bovine tb is to be eradicated, An understanding of the purpose of such measures is vital for them to be fully implemented.

3.3 With regard to the issues relating to controlling disease in the badger population.
In order to eradicate bovine TB from cattle, herds and wildlife hosts a co-ordinated approach is required There is little point in either population becoming infected from the other, and then for the disease to be constantly recycling through the shared environment and contact with infected animals of whatever specie. The current programme of badger culling is proving highly controversial, and polarising the different organisations and agencies involved, who should really have shared objectives to reduce the level of disease burden in all the species affected by the disease. However for a control policy to work it must be supported by those involved. It must be seen to be fair and proportionate and to be mutually beneficial, or at least, not destructive . There is a great danger that the current debacle will further widen the gulf between the parties and diminish the understanding of the different sectors for the others points of view. The problems become further compounded when data and information is then distorted, misquoted and misrepresented to support or dismiss contentions and arguments. None of which is conducive to reaching a consensus on the nature and magnitude of the problems faced both by the livestock industry in maintaining a viable business, nor an understanding of the views of the wildlife sector and public opinion that considers the activities of the livestock sector, in controlling the disease, unacceptable.

At the bottom of this lies the shared ‘ownership’ of the wildlife host(s). The livestock owner is of the belief it is his ‘problem’ to control, the wildlife sector, badger groups, and a significant proportion of the public, believe it is their right that the wildlife host(s) are protected. A potential solution to this conflict of ‘ownership’ is for livestock owners and the local wildlife sectors to work together on management plans to survey, monitor and manage the badger populations on the farmers land or holding. Most landowners are no doubt aware of the setts on their land and could provide information on the activity of the setts and to what extent the badger population interfere with their farming operations. Discussion with Natural England, the livestock owner and the local wildlife organisations could then agree a management plan for the badger population on the farm, which may involve the provision of physical barriers to reduce badger and cattle interaction, what should happen if the population density becomes too great, or certain ‘problem’ badgers are causing undue damage, vaccination if that is deemed the way forward, or for the treatment of setts to increase their resistance to disease and increase immunity by the provision of nutritional supplements.

Such work should also involve assisting the farmer with bio-security measures to decrease badger/ cattle interaction, which could also be achieved with assistance of the local wildlife groups. If management plans can be agreed and implemented, and be subject to annual review, then such measures are far more likely to gain the support, and assistance of the wildlife sector, and the public, to manage the disease risk from badgers, even to the agreement that some populations may require some form of control, or reduction in birth rate.

The management plans could be an extension of the Environmental Stewardship Scheme, or based on a format drawn up with Natural England, farming representative, the Wildlife Trusts, and other agencies. As with the Risk Assessments referred to above, these protocols could be flexible enough to allow for bespoke adjustment to relate to the particular farm or holding, ie with regard to the number of setts and badgers on the holding and how they inter- relate to neighbouring land.

Recommendation
That consideration is given to discussions with Natural England, farming representatives, Wildlife Trusts and other NGOs with a view to providing Management Plans to reach agreement on how badger populations can be maintained and managed on farms and livestock holdings to reduce the risk of disease transmission.

Reason
To provide an ethical, humane and proportionate means of dealing with the risk of transmission from badgers to cattle, which has the support and backing of livestock owners, the Wildlife Trusts, etc and the public.

4 CONCLUSIONS
A co-ordinated and multi-faceted approach is fundamental to reduce the transmission of bovine TB and to move to the elimination and eradication of the disease. All routes of transmission need to be identified and the limitations of the main test, the intra-dermal skin test, must be recognised in determining a control policy. Given these parameters it is important to recognise all the factors that must be considered in slowing the progress of the disease, namely; increasing immunity to infection, the likely presence of disease even when tests do not necessarily show reactors, attention to bio-security, hygiene, cleansing and dis-infection, accurate and swift epidemiological tracing of transmission routes, strict movement controls coupled with pre-movement testing, more frequent testing, reducing inter-action with possible wildlife hosts and reducing the disease within wildlife hosts.

The Research and Development into useable vaccines and DIVA test must be progressed with urgency. Also it is of great importance that the necessary discussions are undertaken concurrently with the EU, OIE, the industry and the export market to enable limiting factors to the use of vaccination to be determined and addressed in advance. Thus enabling the use of vaccination as soon as approval is granted by the EU Veterinary Medicines Directorate for the vaccine and tests.

In addition to these measures it is timely to consider other factors that until now have not been thoroughly appraised. In particular we submit that the studies of Dr Helen Fullerton and the trials conducted by Trace Elements Ltd and Mr Dick Roper require further scrutiny. In the quest to eradicate bovine TB the issue of immunity is an important consideration. Furthermore the role of trace elements in enabling under-detection and persistence of the carrier status requires further investigation.

The enactment of all these measures is a complex process, but by working together with livestock owners, local vets, Defra, AHVLA, Natural England and the wildlife sector a more cohesive approach must be forged to counteract the spread of disease. Identifying all the risks of transmission and responding to them is key to achieving eradication. The joint working of all the agencies, in the preparation of Risk Assessments and Management Plans is crucial to eradicating the disease from the cattle population and greatly reducing the disease in susceptible wildlife.

Animal Welfare Group
October 2012