Monday, January 04, 2010

"Eliminate the Cause"

As another miserable and expensive year of Minister’s non-policy on ‘bovine’ TB has drawn to a close, we have received a sobering overview of the situation from Dr. Ueli Zellweger, a veterinary practitioner of some 30 years experience both in this country and Europe.

Dr. Zellweger explains that after so much experience of treating cattle diseases, testing for TB and the experience in other countries in the eradication of this disease and trading implications surrounding TB, he feels ‘entitled to comment’.
“ When a veterinary surgeon is called out to treat a cow or a whole herd of cattle it is vital that he finds the real cause of the trouble. This may be an infection by either a species of bacteria, virus,a mycosis, possibly interaction with parasites or environmental influences. It is the skill and experience of a successful vet, to discover the real diagnosis and to treat and eliminate the very cause”.
He explains that infections with bacteria are normally treated with antibiotics and disinfectants and subsequent preventative care; and that if an infection is treated soon after starting success is most of times quick and guaranteed. But not so easy to treat are chronic infections.
"Bovine Tuberculosis ( bTB ) in 99% of all cases is a very chronic disease, mainly because of the extremely slow multiplying of these bacteria. Death quite often occurs after suffering over months or even years only. Apart of bTB there are quite a number of other strains causing Tuberculosis; e.g. the human strain ( M. Tuberculosis ), the strain causing leprosy, the avian strains including M. Avium paratuberculosis ( Johne’s disease in cattle and rabbits ) and others which may be even harmless.”
Dr. Zellweger then goes on to explore vaccines, saying that there a lot of vaccines against all kind of infections on the market which normally give quite reliable results if administered correctly in healthy animals and humans.

For Tuberculosis the common vaccine is the BCG which was discovered some 80 years ago and has been used to vaccinate healthy babies mainly. But unlike all other vaccines, Dr. Zellweger explains:
“ BCG does not prevent an infection; it just keeps it from becoming generalized, thus reducing the risk that the bacteria are swept into various other organs followed by massive excretion and transmission of disease ( coughing, urine,milk etc ). There is scientific evidence that the efficiency of BCG is not more than 50% and in a lot of countries it is therefore not in use any longer.”
( Here, we would point out that the ability to excrete large numbers of bacteria varies tremendously between species. In cattle, regularly tested with reactors removed for slaughter, half of the kill will show no lesions at all and no bacteria can be traced even in culture as culture forming units ( CFU ). Of those with lesions, AHOs tell us that they ‘can look for half an hour and still cannot find any bacteria’ on a slide with material from cattle lesions. Conversely the smears from even microscopic lesions found in badgers may contain huge amounts of bacteria, and we make no apology for repeating the answers to our PQs which gave a figure of “up to 300’000 bacteria per ml” which may be found in the urine of a badger with TB in his kidneys. Other questions dragged out the nugget that 30 ml urine can be splattered indiscriminately ( across grassland ) at each incontinent void, and that exposure to just 70 or so bacteria are needed to provoke a positive skin test reaction and possibly onward disease in a cow. Alpacas too seem unlucky enough to develop open lesions very quickly, which may contain large quantities of bacteria, facilitating fast spread within the whole herd. But we digress…)

Dr. Zellweger continues:
" Any animal, group or herd of, with bTB is a focus and as long as a focus is not eliminated it is a high risk for further infections. It is outrageous that these aspects are widely ignored by DEFRA for years now with apparently no end in sight. In 2008 over 40’000 head of cattle reacting to bTB ( skin test ) were slaughtered ( with DEFRA predicting a 10 – 20 % increase annual increase, should the ‘dynamics’ of their non-policy not change – ed ). Nobody knows how many 10’000s of badgers and their setts are infected. Thus the infection within this most relevant wildlife reservoir is permanently spreading, including all its risks of infecting further cattle, other farm animals, pets and humans.”
And on vaccination, as Dr. Zellweger has pointed out many times before:
“Vaccinating badgers cannot be the solution for there are locally far too many badgers and setts which are infected." And in his view, “vaccinating cattle with BCG is absolutely contra-indicated, for the only way of diagnosing bTB in cattle will be seriously compromised.”
( The skin test may react in vaccinated animals, and given the ‘damping down’ effect of BCG previously referred to, animals may still be ‘infected’ but not ‘infectious’ - ed). So, Dr. Zellweger explores another beneficial opportunity:
“ DEFRA thinks to manage to develop a DIVA test thus being able to differentiate between a skin reaction caused by bTB and the one by BCG. It is unclear if such a test will ever reach permission or European wide approbation; however there is a high risk that at some stage various countries will decide , that they are not interested in any English beef products any longer when it cannot be guaranteed that there is no bTB.”
And he points out that “the skin test appears to produce many inconclusive or even false negative results ".( But we are aware that it is testing for exposure to the bacteria which causes disease and not the disease itself – ed ) “And that the Gamma Interferon blood test – apart from being expensive – is quite often hampered by some other influences. There is – (Dr. Zellweger says) – definitely no need of another uncertainty in this whole issue.”

So as the New Year begins, with several hundred head of reactor cattle on the bTB killing lines of abattoirs this week, numerous new breakdowns involving many alpacas which have not yet made it to DEFRAs data sheets and not a few pet cats and dogs, Dr. Zellweger concludes that:
“It is horror for me to see how things are going the wrong way and every month some hundred more Farms are starting suffering dramatically. It is not 5 minutes before noon to rethink this whole
approach by DEFRA – politically steered as it is – NO it is half past noon and even with a quick and total U turn the future of battling bTB looks very bleak. Eradicating bTB in Southwest England will take some 10 years at least, with or without this actual Government and its TB Eradication Group, but with enormous costs, efforts and many more tragedies.”
It is 'a horror' to us as well. And an expensive, futile, bitterly divisive waste of resources. But the gleeful chortle of a young inspector lining up over 200 TB reactors in a Midlands abattoir last week, put it all in perspective. "Another load of cattle who won't be polluting the planet" said she cheerfully. So how many ROC global-warming credits can Defra attach to each reactor's tail?

A Happy New Year.

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