Vaccination can reduce bTB levels in badgers

VACCINATION can significantly reduce bovine TB (bTB) levels in badgers, newly-published research has indicated.

In a four-year study, more than 800 wild badgers in Gloucestershire were captured and injected with the BCG vaccine.

The key result was a 74 per cent reduction in the proportion of badgers testing positive to the antibody bTB blood test, Defra revealed on Monday.

Researchers from the Veterinary Laboratories Agency (VLA) and the Food and Environment Research Agency (Fera) said their study showed a ‘clear effect of vaccination on badger disease’.

But they stressed that, as the blood test is not an absolute indicator of protection from disease, the results do not reveal the degree of BadgerBCG vaccine efficacy. Nor do they provide information on the effect of badger vaccination in reducing TB incidence in cattle.

The field work followed laboratory studies with captive badgers, which had demonstrated that vaccination with BCG ‘significantly reduces the progression, severity and excretion of Mycobacterium bovis infection’

The studies were carried to provide supporting data for the licensing of the Badger BCG vaccine, which was approved by the Veterinary Medicines Directorate in March this year.

A scientific paper summarising the results of the research has been accepted for publication by the scientific journal Proceedings of the Royal Society B (Biological Sciences) and will be published shortly.

Professor Glyn Hewinson, head of the TB Research Group at the VLA, and Professor Robbie McDonald, head of the Wildlife and Emerging Diseases Programme at Fera, said: “In making the data available today, we hope that people will be able to see for themselves the detailed research that went into the development of the vaccine and understand the opportunities and challenges of using vaccination.”

Defra has also published the results of new computer modelling by Fera, which has examined different potential strategies for controlling TB in badgers, including culling and vaccination.

The results were consistent with the conclusions of the Randomised Badger Culling Trial, indicating that there were both positive and negative effects of culling.

The modelling (see box below) showed that badger vaccination could make a ‘positive contribution’ to disease control in its own right and was ‘consistently positive’ when used in combination with culling in a ring vaccination strategy.

The results could prove significant as Ministers develop the Government’s ‘comprehensive’ bTB eradication programme, which they are committed to finalising ‘early in 2011’. A public consultation on Defra’s proposals for badger control, including culling and vaccination, closes on December 8.

The study

The key results of Fera modelling of badger control strategies were:

a) A combined strategy of vaccination in a ring around a culling area was more successful than the cull-only strategy, which in turn was more successful than the vaccination-only strategy, both in reducing the number of TB infected badgers and cattle herd breakdowns. Ring vaccination partly mitigated the detrimental effects of culling. However, the combined strategy requires about twice as much effort than either single approach done in isolation.

b) Culling of badgers should continue for at least four years to realise a clear benefit. However, low rates of land access for culling, or low culling efficiency, or the early cessation of a culling strategy was likely to lead to an overall increase in cattle herd breakdowns (while this is not the case for vaccination).

 The results of the research has been published on the Defra website and is available at: http://ww2.defra.gov.uk/food-farm/animals/diseases/tb/

Readers' comments (17)

  • So the situation is likely to be similar re BCG vaccine for cattle! Abolish the existing bTB policy and let’s have one based on just cattle vaccination! This will save masses of money and be easier for farmers too. There is little evidence given anyway for the continued justification of the current draconian and expensive eradication policy, either on the grounds of costs, human or animal health! 60 years of test/cull in the UK and pockets of TB have always remained and probably always will as the bacteria is so widespread across the world, how can it ever be eradicated? Even in so-called bTB free areas cases spring up with surprising regularity. In fact the government has told us we are still years away from eradication. The existing eradication policy and testing regime is a nightmare for farmers. It is costly and has serious health and safety risks too. It is clear that the existing ‘zero tolerance’ eradication policy is having more of an adverse impact on families than the disease itself. DEFRA does reveal, however, in the latest consultation documents that a vaccination for cattle will be available in 2012 (with DIVA test). The BCG vaccine is not perfect – but then neither is the existing skin (or blood) test and yet it is the skin test that is used to denote whether or not bTB is endemic in an area! Vaccination could be used as a successful control, rather than eradication, policy. However, the EU procedures will not be completed until 2015! This is not good enough and derogation should be sought so a vaccination programme can be started for cattle as a matter of urgency (already successful in Ethiopia where they cannot afford to keep culling cattle! needlessly). Then surely wildlife reservoirs will no longer be a problem!

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  • The existing eradication policy and testing regime, contrary to the anonymous assertion above, is not a nightmare for farmers. It may not be 100% accurate but it has worked and worked well. The nightmare is infected wild animals roaming the countryside spreading TB amongst their own kind and to cattle, when there are legal restrictions on the culling of those animals, but a legal duty to cull cattle.
    Anonymous goes on to tell us that if we vaccinate cattle "Then surely wildlife reservoirs will no longer be a problem!"
    - True, except for the wildlife dying of TB.

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  • Yep, and shooting them can control bTB in cattle. Simple.

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  • They are in a fantasy land. . . We can't even vaccinate all the cooperative human populations successfully. . Publishing results of experiments done with a very limited numbers of badgers is at best specious, and at worst criminally dishonest. . . Anything less than a IOO% success rate would mean surrendering the well being of ALL other mammals to the insidious vagaries of M.bovis just because of hysterical anthropomorphising of the Badger Trust. . . As 'the peasant' says; the nightmare is infected wild animals roaming the countryside spreading TB amongst their own kind and to cattle, when there are legal restrictions on the culling of those animals, but a legal duty to cull cattle.

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  • Quote~:- "understand the opportunities and challenges of using vaccination.”

    We already understand them.

    Professor Glyn Hewinson, head of the TB Research Group at the VLA, and Professor Robbie McDonald, head of the Wildlife and Emerging Diseases Programme at Fera; how much have you both already been paid by the discredited last Labour Government, to waste your time with only a marginally successful injectable animal vaccine?. . . We should be told. . There are millions of elderly who cannot afford the care they need. . And all you seem to care about is blxxdy badgers.

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  • Talk about "Fiddling whist Rome burns"!

    “It happens then as it does to physicians in the treatment of Consumption, which in the commencement is easy to cure and difficult to understand; but when it has neither been discovered in due time nor treated upon a proper principle, it becomes easy to understand and difficult to cure. The same thing happens in state affairs; by foreseeing them at a distance, which is only done by men of talents, the evils which might arise from them are soon cured; but when, from want of foresight, they are suffered to increase to such a height that they are perceptible to everyone, there is no longer any remedy.”

    . . Niccolo Machiavelli 1469-1527

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  • 30 years ago I asked MAFF for scientifically verified evidence of how badgers in the wild actually transmit Btb to cattle. There was none. I more recently put the same question to the Welsh Assembly. They could not provide me with any such evidence. Until it is shown just how badgers transmit this disease to cattle, there should be no cull.

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  • Taken from A VETERINARIAN.
    A site for Vets

    Tuberculosis (TB) is an infectious, granulomatous disease caused by acid-fast bacilli of the genus Mycobacterium. Although commonly defined as a chronic, debilitating disease, TB occasionally assumes an acute, rapidly progressive course. The disease affects practically all species of vertebrates, and before control measures were adopted, was a major disease of humans and domestic animals. Bovine TB is still a significant zoonosis in many parts of the world. Signs and lesions are generally similar in the various species.

    Etiology:- Three main types of tubercle bacilli are recognized: human, bovine, and avian, respectively, M tuberculosis , M bovis , and M avium complex ( M avium-intracellulare-scrofulaceum ). The 3 types differ in cultural characteristics and pathogenicity. The 2 mammalian types are more closely related to each other than to the avian type. More than 30 serovars (distinct variations) of M avium complex are recognized; however, only serovars 1, 2, and 3 are pathogenic for birds. Mycobacteria may survive on pasture for 2 months or more.

    All 3 types may produce infection in host species other than their own. M tuberculosis is most specific; it rarely produces progressive disease in animals other than people and nonhuman primates and occasionally in dogs, pigs, and birds. M bovis can cause progressive disease in most warm-blooded vertebrates, including humans. M avium avium is the only species of consequence in birds, but it has a wide host range and is also pathogenic for pigs, cattle, sheep, deer, mink, dogs, cats, and some cold-blooded animals. Mycobacteria other than tubercle bacilli Mycobacterial infections other than tuberculosis are infrequently isolated from exotic and domestic animals.

    John Bryant ; watch this short film and please try and learn from, Microbiologist, Paul Gillette and Veterinary Pathologist, John Gallagher

    http://www.molevalleyfarmers.com/mvf/info/farming/Bovine_TB_A_Way_Forward

    Up to 300,000 Mycobacterium bovis bacilli have been measured in a single millilitre of badger urine.

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  • Film no longer on line it seems.

    To order a copy see link below. . Essential viewing.

    http://www.chrischapmanphotography.co.uk/btb.pdf

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  • Seems to me, the consultation document was pretty much written with these results in mind. Interesting to note that a vaccine only option would still need the cull of at least 3,667 badgers (much more than the hundreds that would have needed to be gassed) before we will even know if it really works. We've gone full circle and the conclusion is pretty clear; The self proclaimed "animal rights" activists should be ignored.
    http://www.thisisdevon.co.uk/farming/Badger-history-proves-cruel-kind/article-2830247-detail/article.html

    @John, on the Defra web-site there's a lot of research papers etc or failing that the consultation document gives a good run down with references to even more research papers.
    http://www.defra.gov.uk/foodfarm/farmanimal/diseases/atoz/tb/research/index.htm
    http://www.defra.gov.uk/corporate/consult/tb-control-measures/index.htm

    Also worthy of note is the Krebs trial. Their badger dispersal techniques showed how effective badgers were at transmitting bTB to cattle (at least 40-50%).

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