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Let's discuss the BCG vaccine



 Added by  Sally (Guest)
 21 Apr 2010, 3:44 PM


The BCG vaccine is frequently mentioned as the most common vaccine to help protect against TB. It has been used to protect people from the human form of the disease, although more recently in the UK the vaccination programme has been stopped owing to its poor cost effectiveness. An injectable form has recently been licensed for use on badgers. Could it be used for cattle? Is it a reliable vaccination and has it helped prevent the human form of TB?

DaveB
Re cattle vaccine program, looking at the research undertaken before the last election by the Institute of Animal Health and the Jenner Institute ( http://www.iah.ac.uk/research/BovCelImm/BovCelImm_jh.aspx & http://www.jenner.ac.uk/vaccine_prog_bovinetb.html ), they were clearly just a couple of years away from completing their studies.
 
A paragraph from the IAH site reads "... We showed that BCG vaccination of neonatal calves aged less then one month old induced a significant level of protection against experimental M. bovis infection. The duration of immunity induced by BCG vaccination of neonatal calves is currently being assessed and has been shown to be at least 12 months. Our current studies will enable the efficacy of BCG at two and three years post-vaccination to be assessed. One prerequisite for the use of a bTB vaccine is a test that can distinguish vaccinated cattle from those which are infected with bTB. We have developed a rapid, sensitive test that can distinguish BCG vaccinates from infected cattle..."
 
The last line shows that the Diva test is already available.
 
Sally
Some of our supporters have been writing to their MPs about the 'vanishing' vaccine. A letter and standard response received is set out below. We ask why, when they have had decades to work on this, the BCG vaccine for cattle is STILL not available, despite assurances that it would be licensed in 2012.The person who forwarded these letters to us says: 'I am writing back to my MP re the Paice response. I am also planning to issue a FOI request to try and find out why the change from 2012 to some time never!'. We hope others will do the same.
 
Letter to MP: 'During the English consultation on badger culling in September last year Defra stated that they “aim to have a licensed cattle vaccine by 2012” along with the accompanying ‘DIVA’ test capable of distinguishing infected from vaccinated cattle.
 
The vaccine is BCG which has been used on humans for decades and has been trialed in Ethiopia by a team including UK scientists. Martin Vordermeier and Glyn Hewinson from TB Research Group VLA and Doug Young from Imperial College(see attached report). This year Defra are saying that they are “continuing to invest heavily in developing a cattle vaccine and an oral badger vaccine but both are still many years away and we simply can’t say with any certainty when they might be ready to deploy.”
 
This is hardly progress. From an estimate of two years there is now an indefinite delay. There must be a reason for the delay and there must have been an announcement of the change with full reasons. Can you please ask the Minister for a full explanation. Can you also find out what steps the government has taken to change EU law to allow vaccination in anticipation of licensing.'
 
Here is the unsatisfactory response from Jim Paice MP, Minister of State for Agriculture and Food: 'Whilts Defra’s research programme has been designed to minimize the time required to deliver licensed vaccines, research by its nature takes time and a significant proportion of the work can only be carried out sequentially, rather than in parallel. There are defined steps in obtaining a licence (Marketing Authorisation) from the Veterinary Medicines Directorate for vaccines, which include studies to demonstrate both vaccine safety and efficacy. These studies must use the final formulation and therefore cannot start until this formulation is available. Also, large animal experiments take time to run; TB is a chronic disease with a long incubation period, and pathology takes time to progress.
Currently there is no licenced cattle vaccine available. Defra is funding the development and licencing of a vaccine for use in cattle. However, vaccination of cattle against TB is currently prohibited by EU legislation because the BCG vaccine interferes with the tuberculin skin test. Vaccines based on BCG will potentially react to the current tuberculin skin test as if they are infected with TB. Therefore, an important part of the research programme involves developing a test to Differentiate Infected from Vaccinated Animals (a so-called ‘DIVA test). Changes will be required to rhe EU legislation before vaccination can be used. This will not be quick or easy and so is still likely to be many years before a cattle vaccination can be used in the field. Even then other measures will be needed.'
 
becky
Good blog on the Rethink bTB site at http://www.rethinkbtb.org/blog.html#home
 
Vanishing Vaccine
 
During the English consultation on badger culling in September last year Defra stated that they “aim to have a licensed cattle vaccine by 2012” along with the accompanying ‘DIVA’ test capable of distinguishing infected from vaccinated cattle. The vaccine is BCG which has been used on humans for decades.
 
This year they are saying that they are “continuing to invest heavily in developing a cattle vaccine and an oral badger vaccine but both are still many years away and we simply can’t say with any certainty when they might be ready to deploy.”
 
This is hardly progress. From an estimate of two years there is now an indefinite delay.
 
There must be a reason for the delay.
 
There must have been an announcement of the change with full reasons.
 
Well, if there was an announcement it was very discrete, and no reason can be found. We have Stephen Crabb MP on the case, and hope to bring you a detailed explanation soon.
 
We have also asked him to find out what steps the government has taken to change EU law to allow vaccination in anticipation of licensing.
 
becky
Parliamentary question dated 4/2/11 to the Commission, Rule 117, Emma McClarkin (ECR): 'A constituent has written to me about bovine TB and EU Directive 78/52/EEC. I would like to ask the Commission if it can estimate how much the slaughter of infected cattle costs the European taxpayer, and secondly, can the Commission explain why, if an effective vaccine were developed, its use would be prohibited by the EU Directive?'
 
Response dated 8/3/11 given by Mr Dalli on behalf of the Commission:
 
'In the framework of a TB eradication programme, approved by the Commission for the financial contribution from the Union, the financial contribution by the Union is set at 50 % of the costs incurred by each Member State for the compensation to owners for the value of their animals slaughtered, subject to an overall ceiling per programme. The maximum amount reimbursed to a Member State for the slaughter of an individual TB infected animal is EUR 375 per animal slaughtered.
 
Information on the outcome of the UK 2010 programme has not yet been received by the Commission, but it was estimated that approximately 49500 TB reactor animals would be slaughtered in 2010.
 
As regards the prohibition on TB cattle vaccination, EU and international (OIE(1)) rules on TB are based on current and historical knowledge of TB vaccines and diagnostic tests. Current rules do not allow the use of vaccines against TB in cattle mainly due to the interference with the only official test (skin test) and the suboptimal effectiveness of existing vaccines.
 
If a candidate vaccine succeeds in showing scientifically sufficient protection and no interference with diagnostic tests, this vaccine might be an additional tool to accelerate TB eradication under certain circumstances. For this, EU and international (OIE) rules will need to be substantially amended.'
:
 
becky
News from http://www.eurekalert.org/pub_releases/2011-10/uoe-cpv102711.php
 
Scientists have developed a technique using a harmless parasite – which lives in cows but has no effect on their health – to carry medicines into the animals' bloodstream. Research suggests this new approach to vaccinating cattle could help farmers worldwide, research suggests
 
Researchers created the vaccine by inserting key genetic material from a vaccine into the parasite's DNA. The manipulated parasite is intended to be injected into cattle, where it would continue to thrive in their bloodstreams, releasing small amounts of vaccine slowly over time.
 
The treatment could offer long-term protection against common conditions, including bovine tuberculosis, as well as a range of other diseases.
 
The research, carried out in collaboration with the Moredun Research Institute with funding from the Wellcome Trust and the Biotechnology and Biological Sciences Research Council, was published in the journal PLoS Pathogens.
 
Professor Keith Matthews of the University of Edinburgh's School of Biological Sciences, who led the research, said: "This method has real potential to control a wide range of cattle diseases throughout the world. It is also a fantastic example of how building on many years of basic scientific research can lead to unanticipated economic potential."
 
Sally
Email from PT 10/10/11
 
But despite the lengthy story on the testing and the ins and outs, I do find some optimism from slide "the future" near the end. He concedes the lack of public health benefit and hence concedes bTB is just an animal disease and it is trade that is driving legislation. He even agrees that the inhalation risk of transmission from cattle to humans is very small. This is quite something....
 
But when the value of the trade is a small fraction of the cost of the "cure", then clearly the legislation needs to change....
 
becky
The documents from a presentation 'Bovine TB Where Are We Now' held in Feb 2011 are interesting. http://www.rabdf.co.uk/DynamicContent/Documents/Carl%20Padgett%20Presentation%20College%20Lecturers%202011.pdf
 
The bits on the skin test (and other tests) are indeed interesting and much of info echoes that of the discussion paper by the think tank Rethink Bovine TB, 'Bovine TB, Time for a Rething' (www.rethinkbtb.org) , in particular with similar concerns regarding accuracy. This section should be read carefully. It clearly reveals just how imperfect the skin test is. Those delaying the implementation of cattle vaccination give the reason that vaccination is not effective enough - however, it could well be that it would be more effective bearing in mind the policy is currently based solely on an imperfect skin test. Of great concern is that towards the end of the presentation, when discussing cattle vaccination for bTB and need to change EU legislation it states there is 'little if any appetite for this' - giving dates as 2015, 2020 and 2025? If this is correct how could Defra have got it so wrong in their 2010 consultation papers?
 
It is suggested we learn from countries like Australia, New Zealand and the Americas - skin test is used as it was designed for - as a herd test so any reactors and the whole herd is slaughtered with long term stocking delays - never suggested for UK (thankfully).
 
Some contradiction - Outcomes of Human Exposure seems to be unnecessarily pessimistic (and, for some reason, compared with Ethiopia?) when much later (towards end of presentation under 'The Future') they ask 'where is the public good in controlling bTB?' and confirm risk to humans is low becuase of pasteurisation and 'little evidence of inhalation risk from cattle to humans'. Yet again we are not told why, with such low risks, bTB needs to be dealt with so much more rigidly than any other disease/zoonosis.
 
Information on dealing with wildlife reservoirs is confusing as appears to contradicts other scientific reports.
 
A few misleading phrases are clarified. Let's not forget that OTF means 'free to trade' - not necessarily bTB free. Sadly nothing in here about the terminology relating to the skin test and how many cattle are actually being killed needlessly because they have merely been exposed to the bacteria that causes bTB.
 
Interestingly looking at the graph 'Is bTB improving' which goes up to 2009 (I assume this is England and Wales), it shows it is declining from its peak, despite the number of tests increasing with WAG apparently reporting a 14% reduction in new incidents and 28% less animals slaughtered in first 10 monthsof 2010 10 months of 2010
 
Sally
This is encouraging ) - abstract extracted from www.curehunter.com/public/pubmed21420804.do)
 
In this review, the status of vaccination strategies to reduce bovine tuberculosis of cattle and wildlife reservoirs of the disease is discussed, with a focus on recent developments. Recent work in vaccines to protect humans against tuberculosis has been followed by a similar surge of interest in developing vaccines against bovine tuberculosis. The human vaccine, bacille Calmette-Guérin (BCG) affords protection against tuberculosis in cattle, but this protection is variable. In addition, vaccination with BCG compromises control strategies based on skin testing animals. In general, no single vaccine approach has shown itself to be significantly superior to BCG alone, however, vaccine combinations of BCG and vaccinating moiety such as adjuvanted subunit, virus vectored or DNA vaccines have been shown to induce protection superior to that achieved by BCG alone. Vaccinating wildlife species against tuberculosis is also an area which has been subjected to scrutiny. Recent work has focused on vaccinating wildlife orally, via the use of BCG formulated in baits consumed by these species. Results from trials in a number of animal species indicate that oral BCG vaccination can reduce disease severity following experimental challenge with Mycobacterium bovis and in a recent field trial, oral BCG vaccination was shown to prevent infection of wild possums following natural exposure to M. bovis. In conclusion, recent studies in cattle and wildlife have demonstrated the practicality and effectiveness of vaccinating animals against tuberculosis and provide much impetus for future use of vaccines.
 
becky
http://biosecurityresearch.blogspot.com/2011/09/how-much-did-mps-understand-about-rbct.html
 
This really is a must read! The notes from the seminar held for MPs in 2004 contain some useful information - it reveals how little we have progressed and how little is known about this disease and the efforts to control or eradicate it ...
 
Bourne's comments are particularly enlightening. He acknowledges skin test has failed yet it would seem that in reality we STILL have no real prospect of change in the near future (despite next year being given as date for cattle vaccination to be licenced with Diva test. There is the continuing obsession with badgers which - yet again, monopolize the debate. Bourne admits if badgers were eliminated overnight the disease would remain ...
 
We have pulled out a few of the extracts we found most interesting and reproeduce these below.
 
To answer the question, 'What is the good news that I can take back to my farming friends?', we have this response: 'there is a lot of good news. We better understand the disease in cattle. We recognise that the diagnostic test as it has been applied in the past 20 years has been inadequate for controlling the disease in cattle and has to be improved. The nettle has been grasped with respect to that and the use of the tuberculin test is now being looked at more forcibly and also changed in the field. There is also development in other tests'
 
So where is the real progress re this now we are in 2011?
 
'We also recognise the dangers of moving infected cattle around the
countryside. Farmers must recognise that they have a responsibility for treating it as an infectious disease and putting in place rather simple biosecurity measures to prevent the transmission. We have moved a very long way in a very short time. The culling issue is still vexed, but I honestly believe that, if one eliminated badgers at a stroke over night, we would still be left with a very serious cattle disease that would have to be tackled in a way that would have to be more effective than has been used in the past 20 years'.
 
Page 9 .... 'Although we have talked continually about a reservoir of infection in badgers, on the basis of work that has been in place for the past couple of years we now recognise that there is a reservoir of infection in cattle. That would not be controlled by killing badgers. It
has to be tackled in some other way'.
 
... and on the subject of other animals ... 'Other wildlife reservoirs have been mentioned. We recently completed a report in which we concluded that deer, especially fallow and red deer, may constitute maintenance reservoirs of tuberculosis'.
 
.. and on subject of closed herds .. page 14, Professor John Bourne: 'The TB 99 epidemiological analyses suggest that there is no such thing as a closed herd. People claim to have a closed herd, but they simply do not exist'.
 
---
and on subject of cattle vaccination Page 23 ... 'It has been said that, epidemiologically, we can only get it right about half the time. I understood that cattle vaccination through the normal vaccination that we would give people is only about 60 per cent. effective. Surely, if we can reduce the amount of bovine tuberculosis by 60 per cent. we will have done a tremendous amount of good'.
 
Professor Doug Young said; 'Vaccination will reduce it by 60 per cent., but it depends on what is defined as a reduction. That does not mean that 60 per cent. of the animals do not have any disease at all. It tends to reduce the amount of disease in individual animals, so they would still remain, for example, tuberculin positive. It would be a problem with the current BCG. We have to go further than the current BCG to really get to a stage where we do not have the significant number of lesions in the animal to make it worthwhile.'
 
'The progress that we are moving to in terms of better BCG would be that,
since the Krebs report, there has been an active programme of cattle vaccination in place. People have been looking in laboratory experimental challenge conditions and now have vaccines that look better than BCG. We are now trying to put those out into a natural transmission setting, so in the laboratory we are looking at quite an unfair situation where we give cattle a very large dose. It may well be that, under natural
conditions, they see a lower dose and our vaccines may be suitable for that. At the moment, we have had five years in the lab. We are now going into a five-year phase where we can evaluate the new vaccines under natural transmission settings. We have plans in place. We can go ahead'.
 
WE ARE STILL WAITING!
 
Bill Wiggin MP: 'Is more money being used to do that quicker?'
 
Professor Doug Young: 'We are certainly going to use more money over the next year. That has been put into the DEFRA programme. At the moment, a certain amount of money has been going into the basic research to produce the candidates. Our plans for testing them in natural transmission settings mean that we need to assemble herds of reactors in some kind of contained facility and put in our vaccinated animals and see what happens. That experiment is quite expensive. It will cost several millions of pounds ...'.
 
geoffrey
It is amazing that vaccination of cattle a year ago was seen by British Scientists as being a perfect solution for bTB in other countries but somehow not for the serious TB problem in UK cattle! Many of their excuses are actually invalidated by their own research reported in the paper mentioned in the last posting.
 
Farmer
In the paper from way back in 1909 (relating to bTB) says "None of the various methods for the immunization of animals against tuberculosis has passed beyond the experimental stage". So why is it that a Century later and after £ millions spent we are still not able to vaccinate our animals against bTB. I would like to know why the NFU is so obsessed with badger culling and not pushing for a cattle vaccination?
 
Here is a quote I saw recently from Professor John Bourne, Chairman of the Independent Scientific Group - The Randomised Badger Culling Trial:
 
"If one eliminated badgers at a stroke over night, we would still be left with a very serious cattle disease that would have to be tackled in a way that would have to be more effective than has been used in the past 20 years"
 
A paper Field Evaluation of the Efficacy of Mycobacterium bovis Bacillus
Calmette-Guerin against Bovine Tuberculosis in Neonatal Calves in Ethiopia (Ameni and others 2010)) published June 10 ((http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2543804/pdf/amjphygiene00004-0113.pdf)) . This paper relates to the field experiment in Ethiopia with Holstein cattle. It demonstrated that the BCG vaccination can prevent disease in a substantial proportion of cattle as well as significantly reduce pathology in others.
 
'Bovine Tuberculosis: The Governments approach to tackling the disease',
Annex D - Veterinary assessment on vaccination, September 2010 says
 
20. A review of the effectiveness of BCG vaccine in animals was conducted by Suazo et al. (2003). They state that, in cattle, "vaccination decreased infectiousness of infected animals (rather than by preventing infection) by reducing the size of lesions and the burden of mycobacteria." However, the efficacy of BCG in laboratory infection studies may be underestimated as artificially high doses of M. bovis are commonly used to induce experimental infection. In settings of natural transmission from infected animals to vaccinated individuals, BCG vaccination may confer complete protection from disease in some vaccinated individuals.
 
Sally
On behalf of a constituent the following question was asked in February 2100 (http://www.europarl.europa.eu/sides/getDoc.do?type=WQ&reference=E-2011-000827&language=EN( by Emma McClarkin, MEP, '... can the Commission explain why, if an effective vaccine were developed, its use would be prohibited by the EU Directive?'
 
European Commissioner for Health and Consumer Policy, John Dalli replied (E-000827/2011)
 
'In the framework of a TB eradication programme, approved by the Commission for the financial contribution from the Union, the financial contribution by the Union is set at 50 % of the costs incurred by each Member State for the compensation to owners for the value of their animals slaughtered, subject to an overall ceiling per programme. The maximum amount reimbursed to a Member State for the slaughter of an individual TB infected animal is EUR 375 per animal slaughtered. Information on the outcome of the UK 2010 programme has not yet been received by the Commission, but it was estimated that approximately 49500 TB reactor animals would be slaughtered in 2010.
As regards the prohibition on TB cattle vaccination, EU and international (OIE(1)) rules on TB are based on current and historical knowledge of TB vaccines and diagnostic tests. Current rules do not allow the use of vaccines against TB in cattle mainly due to the interference with the only official test (skin test) and the suboptimal effectiveness of existing vaccines.
If a candidate vaccine succeeds in showing scientifically sufficient protection and no interference with diagnostic tests, this vaccine might be an additional tool to accelerate TB eradication under certain circumstances. For this, EU and international (OIE) rules will need to be substantially amended.' (http://www.warmwell.com/eubtbanswer.html)
 
Sally
http://www.badgerall.com/blog/early-one-morning-just-as-the-sun-was-rising
 
Interesting account about the FERA cage trapping and vaccination course from someone who recently attended and is now certified as a lay vaccinator of badgers.
 
Interestingly the course included an overview of the history of TB in cattle and the various strategies that have been tried to prevent or control – and now ‘eradicate’ it. The graphs showing the incidence of bovine TB over various periods were fascinating – and we are told did not seem to support the oft heard claim that the introduction of legal protection of badgers led to a rise in incidence of TB. Between 1935 when a voluntary attested herds scheme was introduced and 1960 when ‘all herds in GB were ‘attested’ – the number of cattle slaughtered plummeted and bTB incidence was negligible, clearly under control. But it seems they didn’t continue with this eminently successful strategy. Another graph depicting Badger Control History and the relative incidence of cattle tb from 1965 to 2008 apparently showed it remained pretty much under control across England and Wales overall from 1965 to 1980 (with a higher level of incidence in South West England) – but starting to rise steadily everywhere from 1985 onwards. We are told this rise coincided with the time that an ‘interim strategy’ of trapping and shooting badgers on infected farms was adopted. What would have been good to look at alongside this would have been the relative testing regimes in place, and also the relative pattern and frequency of cattle movements throughout the periods.
 
Sally
What is bovine TB? Why are we set to cull huge numbers of badgers to deal with it? Why can't we use a bovine tb vaccine? Cattle farmer and permaculturist Tim Green answers some of these questions - and poses more - in an excellent and very thought provoking article at
 
http://www.permaculture.co.uk/articles/1608111008/bovine-tb-badgers-and-permaculture-perspective
 
becky
Interesting post on Warmwell (http://warmwell.com/jan11ruth.html) 8/8/11 is response from Dr Colin G Fink, Clinical Virologist & Hon. Senior Lecturer in Biological Sciences University of Warwick who discusses the immunity issue. He confirms that 'any mammal that comes into contact with Mycobacterium bovis, and remains well, will develop antibodies and a white cell memory for the bacterium which may cause no clinical disease, but become walled up within the animal's tissues. Probably some animals (camelids and occasional cattle in a herd come to mind) have a poor ability to develop any host response to this organism and they may become overwhelmimgly infected with many lesions and then die. They represent a serious infection risk in this state but may remain undiscovered until late on in the disease process. For most animals this is not the normal course of events and they resist the organism and remain well.'
 
He goes on to say the same applies to man and meeting Mycobacterium tuberculosis. Later on in life or under stress,( for example perturbation of badger social groups by culling) they may have a recrudecence of this infection and become clinically infected and excretors of the organisms.
 
Most cattle that are skin test positive have been exposed to the organism but remain healthy. However, they are culled as a precaution.
 
He goes on to discuss badgers and ends by saying that 'At present there is no ideal solution. I am of the opinion that feeding and including trace elements to the badgers ( and other herbivore/omnivore wild life reservoirs) along with hormones to limit reproduction, may be a useful experiment to undertake. I have previously suggested mixed antibiotics in the feed. Maybe this is a way forward and worth a serious trial?'
 
becky
Email from BF dated 31/7/11:
The best answer to this long running problem would be to vaccinate all cattle and to persuade farmers to block badgers to stop them from joining cattle when they are grouped in barns as pictured in a recent BBC Countryfile programme! Had the farmer concerned not heard of Electric fences etc? As a boy I had Bovine TB from helping deliver untreated milk on my bicycle into jugs and bowls on doorsteps from a stainless steel container. I also caught Scarlet fever. However Vaccination came along and myself and a large family of relatives never succumbed to other deadly diseases simply by being vaccinated by needle and by mouth. So why all the fuss in avoiding such modern methods these days on cattle? Think of the savings to the farmers and taxpayers this ridiculous Government course of action has and still is costing at a time when we need to get the economy thriving again.
 
becky
In Defra's infamous badger consultation paper we were told that a cattle vaccine would be licensed in 2012 and it would take until 2015 to obtain the necessary EU approvals. However, recently Caroline Spelman, State for Environment, Food and Rural Affairs, has admitted that an approved cattle and an oral badger vaccine were still "much further away than we thought". This is inexcusable and one wonders exactly what is happening and what is being hidden from us?
 
www.defra.gov.uk/news/2011/07/19/next-steps-to-tackle-bovine-tb-in-england-2/
 
Sally
There are some interesting posts about vaccination at www.warmwell.com, including an email from farmer, virologist and wildlife conservationist, Dr Ruth Watkins - www.warmwell.com/badgervaccines.html
 
Sally
We keep hearing (from main stream media reporters, well known presenters and others) that in some EU countries (France and Germany) cattle are vaccinated using the BCG vaccine. This is illegal and we have not yet been able to substantiate such rumours so we would be interested in hearing from anyone who can substantiate such claims.
 
I have found a mention of the BCG vaccine being used in Germany in the 2003 edition of 'A Guide to Child Health' by M Glockler and W Goebel (first published 1984). On page 168 under 'Tuberculosis (BCG Vaccine' it states '... More important in this regard are: ... vaccinating cows and pasteurising milk from farms that cannot be reliably certified as TB-free'.
 
becky
Interesting news item in the summer 2011 newsletter of the Small Farms Association. It relates to bluetongue disease and not bovine TB but there are some interesting parallels.
 
Apparently restrictions on exporting sheep and cattle from GB as a result of bluetongue disease will be lifted on 5 July 2011. Bluetongue free status enables the UK to export animals to other bluetongue free countries.. Oddly we are told that after 5 July we will no longer be able to vaccinate for this disease as EU law will prevent this!
 
The original restrictions were imposed in 2007 following the first case of bluetongue found in the UK - thought to have been from midges blown over from the Continent. The last notified case was in 2008 and the UK has demonstrated to the European Commission that no cases have been reported for the last two years. The disease affects all ruminants and is spread by biting midges. It causes a reduction in milk yield, abortions, deaths and reduced fertility.
 
There have been no reports of active bluetongue in Northern EU Member States, and Hungary, Denmark and Sweden have all been declared disease free with other countries suspected to follow later in 2011.
 
The Bluetongue Directive doesn't allow animals to be vaccinated unless a bluetongue zone is in p;ace, then export restrictions apply. The UK Government is pressing the EU to change this so vaccination can be used more flexibly.
 
becky
Why can we not move to a control, rather than eradication policy? This would mean we could rely mainly on cattle vaccination. Whilst the effectiveness rate for the BCG varies in cattle most of the trials have shown it will reduce the severity of infection and prevents spread of the disease. Why has there been so little progress re cattle vaccination when research done some years ago has suggested it is a viable option?
 
Interesting Defra research project final report (SE3212 'Testing TB Vaccines in Cattle') from 1999 - 2005 at http://randd.defra.gov.uk/Document.aspx?Document=SE3212_2831_FRP.doc which confirms that 'Cows receiving prior BCG vaccination develop markedly fewer visible lesions, and fewer bacteria can be recovered from their lymph nodes. BCG vaccination was more effective when delivered to neonatal calves than to older animals. This could be due to a difference in the neonatal immune response, or to a detrimental effect on BCG vaccination caused by exposure of older animals to environmental mycobacteria.'
 
An interesting conclusion in a study publised in 2002 'A review of M. bovis BCG protection against TB in cattle and other animals species' by Feliciano Milian Suazoa,*, Ana Marõ Âa Anaya Escaleraa and Ruth M. Gallegos Torresb
(www.sciencedirect.com/science/article/pii/S0167587703000035)
 
'A strong argument against vaccination in TB-control schemes in cattle is that it interferes with the tuberculin test. Either DNA vaccines or vaccines based in mutant strains of M. bovis or M. bovis BCG (mutants which do not cause response to the tuberculin) could solve this problem, and such vaccines are already in the laboratory (Hewinson, 2000). We conclude that M. bovis BCG might be used in TB-eradication programs to reduce the prevalence of the disease to a point where the strategy of test-and-
slaughter is economically feasible especially in dairy operations in developing countries where the prevalence of the disease is high. BCG has efficacy in protecting against the development of lesions and bacillus loads in internal organs; this prevents the spread of the disease in populations.'

 
Michael
It seems that vaccination against Bluetongue was allowed because other means are ineffective (just like bTB I hear you all say). Does this show a degree of flexibility that Defra could exploit to get cattle vaccination allowed?
 
I would not be surprised if Defra were inventing obstacles to a change in EU law or a derogation to protect the status quo as bureaucrats tend to do.
 
http://ec.europa.eu/food/animal/diseases/index_en.htm
 
Control measures against major epizootic diseases, essentially list A OIE diseases, such as foot-and-mouth disease (FMD) and classical swine fever (CSF), to be taken as soon as a disease is suspected.
 
In case of a disease outbreak the animals in the infected holding are culled and their carcasses destroyed to interrupt the chain of infection as quickly as possible. When deemed necessary, preventive culling of animals in suspect (contact) farms may also be applied. Emergency vaccination can be used as an additional measure to achieve eradication. Generalised preventative vaccination against FMD and CSF is not applied. as it may "hide" the infectious agents and favour disease spread. However, for some diseases, such as bluetongue, which may not be effectively controlled by other means, vaccination is applied as the most important disease control tool.
Michael Ritchie

 
becky
The Secretary of State for Environment, Food and Rural Affairs has confirmed that vaccination will have a role in the future control of bovine TB. he was responding to questions raised. See below.
 
http://services.parliament.uk/hansard/Commons/bydate/20110607/writtenanswers/part013.html (7/6/11)
 
Questions to Secretary of State for Environment, Food and Rural Affairs from Charlotte Leslie: To ask the
 
(1) what recent assessment her Department has made of the efficiency and viability of inoculating badgers against bovine tuberculosis; and if she will make a statement; [56859]
 
(2) what her policy is on the level of evidence required in respect of the viability of inoculation of badgers to establish that method as a means to prevent the spread of bovine tuberculosis. [56860]
 
Reply from Mr Paice:
'A licensed injectable badger TB vaccine is already available for use on prescription. Experimental studies have demonstrated that vaccination is safe and effective in reducing the progression and spread of TB in badgers. DEFRA is funding a Badger Vaccine Deployment Project to assess the practicality of vaccination in the field and to train lay vaccinators. However, while we would expect vaccination to result in reduced transmission of bovine TB to cattle, we currently have no hard evidence on this. Therefore, the precise contribution vaccination could make to reducing disease in cattle is unknown.'
 
'It is important to note that vaccines can never represent a single answer to the problem of bovine TB. Vaccination is a risk reduction measure, most likely to be successful in controlling bovine TB when used alongside other disease control measures.'
 
'Despite the relative lack of scientific evidence, the public consultation document made clear that we do see a role for vaccination. We are carefully considering the large number of responses we received to the consultation.'
 
becky
A more effective TB vaccine (see http://stoptb.citizen-news.org and http://www.medindia.net/news/Effective-TB-Vaccine-81198-1.htm) has been produced. According to the Asian News International, 21 February 2011, researchers have improved the effectiveness of the vaccine for tuberculosis. The work was done by Nele Festjens and Nico Callewaert of VIB and Ghent University. It is alleged that the new vaccine affords - as already proven in mice - better protection against the disease.
 
The bacterium from which the BCG vaccine is derived 'hides' from the immune system of the organism in which it ends up when it should really trigger an immune reaction in order to be able to afford the best protection. Festjens and Callewaert have discovered that the bacterium hides behind the SapM enzyme that acts as a kind of shield.They have used this knowledge to develop the new vaccine. They adapted Mycobacterium bovis BCG in such a way that it was no longer able to generate SapM and could therefore no longer hide from the immune system. Testing the new vaccine on mice has shown that it affords better protection than the present BCG vaccine. "Our vaccine is more effective because it is more quickly recognized by the immune system of the vaccinated person. We have, as it were, undressed the existing vaccine by removing its protective shield," said Nico Callewaert.
 
Keith
In January a BBC news item (www.bbc.co.uk/news/health-12224172) reported on a new vaccine (developed by Danish scientists) that can fight tuberculosis (TB) before and after infection. This could apparently offer protection for many years more than is now possible. I wonder if this could be used for bTB?
 
The human form of TB is a disease of the lungs, causing symptoms such as coughing, chest pains and weight loss. However, only in a small number of cases (estimated to be fewer than 5%) do the symptoms develop immediately after infection. In more than 90% of cases, once Mycobacterium tuberculosis, the bacterium which causes the disease, has invaded the body it changes its chemical signature, and lives in a dormant (latent) - state, as with bTB.mUsually the bacterium never emerges from this latent state, but in around 10% of cases it does reactivate, often years or even decades later - to trigger severe symptoms. Current vaccines, such as the BCG vaccine, apparently work only if given before exposure to the bacterium. They do not prevent infection, but do prevent acute symptoms and disease from emerging. But once the bacterium has changed into its latent form it is effectively immune to the vaccine, and can bide its time, reactivating after the vaccine has ceased to have a preventative effect. If successful in human trials, the new vaccine would be able to tackle that problem.
 
Developed by a team at the Statens Serum Institute in Copenhagen, it combines proteins that trigger an immune response to both the active and latent forms of Mycobacterium.The number of tuberculosis cases in the UK topped 9,000 in 2009 (only 0.05% of these cases were bTB) - the highest for nearly 30 years. Despite the greater risk to humans and the increasing number of cases, there is no expensive eradication programme for the human form! There has also been a sharp rise in drug-resistant TB cases. The Health Protection Agency has warned more efforts must be made to curb the problem. Maybe the current resources being channelled into eradication of bTB in cattle should be transferred instead to dealing with tuberculosis in humans!
 

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