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Five letters in 2009 from the Swiss vet (now living in the UK), Dr Ueli Zellweger MRCVS GST TVL
Email from Dr Zellweger Feb 4 2010
Why BCG does not perform like other VaccinesIn any normal infection the body defence works by production of vast amounts of antibodies. Such antibodies can also be stimulated by ordinary vaccines for all kinds of bacteria and virus diseases and they can be traced in blood which makes diagnosis with various techniques fairly easy.
But this does not work for Tuberculosis - it never did and it never will do - because the tubercle bacteria have a waxy coat to which antibodies cannot attach. Tuberculosis therefore causes a so called humoral body defence; that means the very slowly multiplying bacteria are attacked by enzymes and white blood cells mainly. These are killing or even digesting the bacteria by a method called phagocytosis resulting in crumbly pus in the so called tubercles - whole heaps or lumps containing several 1000 to billions of bacteria.
This defence is much more unspecific and slower than the usual one by antibodies.
Any BCG vaccine stimulates this humoral defence only but never prevents an infection; it may keep it on a low scale maybe. There is no other vaccine available and there most probably will never be another one.
No matter how many millions more DEFRA invests ( I hear of some 30 so far for the Vaccine only ) this is nature - which cannot be forced by politics.
Dr. Ueli Zellweger
Email received in reply to Dr Colin Fink (here) On the subject of Antibiotics and Contraceptives for Badgers Dr Zellweger writes:
"Having used all kind of available antibiotics and contraceptives in my veterinary practice I dare to inform that it is most unlikely to find any way to administer either of those at the right time in the adequate dosage.
A cure with antibiotics would have to be maintained over 6 months with daily intake. Any person who has ever tasted 3 0r 4 granules ( some 0.2 grams) of antibiotics would be amazed and embarrassed how bitter or disgustingly strange tasting antibiotics normally are. There are antibiotics with improved acceptance when administered highly diluted e.g. in a soup; but then those showed no efficiency against bTB. Dr P Gillett's idea of resistance is highly valid.
How to guarantee that of a sett with some 10 badgers every inhabitant gets the right daily dosage over several months?
As to contraceptives for animals: These are normally applied in females and in the period when they are sexually absolutely inactive. Who knows? It is very tricky to say for how long one treatment is effective. Again, as with antibiotics, the correct dosage is vital and has to be used according individual bodyweight.
The oldest sow might be almost double the size of her daughters and when all females of a sett are treated there is good risk that the pecking order is sooner or later getting upset, apart of the fact that with each and every hormone therapy there is a risk that something goes wrong.."
Email received December 30 2009
DEFRA and bovine TBAfter some 30 years as a country vet for cattle mainly I feel entitled to comment.
When a vet 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. Quite often this is an infection by a species of bacterium, virus, a mycosis or when there are parasites involved. It is common that there is a mix or environmental influences e.g. a draught in the calf shed.
It is the skill and experience of a successful vet to find the real diagnose and to treat or eliminate the very cause.
Infections by bacteria are normally treated with antibiotics and disinfectants and subsequent preventing methods. If an infection is treated soon after starting success is most of the time quick and guaranteed.
Not so easy to treat are chronic infections. Bovine Tuberculosis ( bTB ) is in 99% of all cases a very chronic disease, mainly because of the extremely slow multiplying of these bacteria. Apart from bTB there are quite a number of other strains causing Tuberculosis like the human strain, the strain causing leprosy, the avian strain, Mycobacterium paratuberculosis ( Johns disease ) and others which are even harmless.
There are a lot of vaccines against all kind of infections on the market. They normally give quite reliable results if administered correctly and in healthy animals ( and humans ). For Tuberculosis the common vaccine is the BCG which was found some 80 years ago and has been used to vaccinate healthy babies mainly. BCG does not prevent an infection like all other vaccines; it just keeps it from becoming generalized, thus reducing the risk that the bacteria are swept into various other organs followed by massive excretion ( coughing, urine, faeces, 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 used any longer.
Any animal, group or herd of with bTB is a focus and as long as such 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 absolutely no end in sight. In 2008 over 40,000 head of cattle reacting to bTB were slaughtered (10 % annual increase to be expected ) and nobody knows how many 10,000s of badgers and their setts are infected. Thus the infection within this most relevant wildlife reservoir is permanently growing including all its risks of infecting further cattle, other farm animals, pets and humans.
Vaccinating badgers cannot be the solution for there are locally far too many badgers and setts infected and vaccinating cattle with BCG is in my view absolutely contraindicated for the only way of diagnosing bTB in cattle will be seriously compromised.
DEFRA thinks to manage to develop a DIVA test thus being able to differentiate between a skin reaction caused by bTB and the one caused by BCG. It is unclear if such a test ever will reach permission or Europeanwide approbation; however there is a high risk that some countries will decide at some stage that they are not interested in any English beef products any longer when it cannot be guaranteed that there is no bTB. The routine bTB skin test alone in many cases is unreliable enough ( inconclusive or even false negative results ) and the Gamma Interferon bloodtest - apart from being expensive - is quite often hampered by some other influences. There definitely is no need of another uncertainty in this whole issue.
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 U turn the future of battling bTB looks bleak.
Tuberculosis and DEFRA - a Political Tragedy?
email received December 16 2009
Sir, During my long career as a country veterinary surgeon, nature taught me time and time again that if there is trouble with animals you have to find and eliminate the source. If it is an infection then the species of bacteria, virus or mycosis needs to be treated adequately. If you fail to get rid of these sources of infection then sooner or later there will be more trouble and misery. It is exactly the same as toothache.
With tuberculosis an infected animal or herd is a focus. If you do not manage to eliminate that focus or if you do not even try to do it, the problem will get worse. Vaccinating before the herd is clean will definitely make things worse.
If politicians continue to ignore the advice of experienced veterinary surgeons about how to get rid of bovine TB, nature will hit back and teach them a lesson or two. Nature does not look back, does not care how much money is spent, she just keeps going her own way.
Vast amounts are being spent both on compensation and on future schemes. This money will be totally wasted unless the government is brave enough to accept the fact that huge reservoirs of bovine TB lie in the overcrowded badger population. Some 40,000 head of cattle are being culled every year due to TB and this figure is rising by 10% per annum. It is unclear how many ten thousands of badgers are infected and are further spreading this disease. DEFRA seems to ignore or tries to vaccinate even diseased badgers which could well induce further spreading.
Maybe the government also needs to consider the welfare of the whole badger population. Death by TB is extremely slow, miserable and painful. Finally bovine TB can also be infectious to humans and some domestic animals ……
Dr Ueli Zellweger MRCVS GST TVL
What Happens In A Badger Sett With Bovine Tuberculosis?
It is not unusual that badger setts are several hundred years old. They consist out of various dens and chambers, well connected and spread out over some 20 to 50 yards 1 to 10 feet underground. Badgers are night active creatures and during wintertime they spend most time sleeping or dosing socially cuddled up in their dormitories ( see BBC autumn or spring watch ). In the open the family of a sett normally has a territory of up to 1 or even 2 square miles which is well defined and regularly marked by urine and latrines. In the dens and chambers the climate being obscure with sticky air and steady temperatures of some 10 - 20 degrees is ideal for numerous bacteria and other germs.
The Badger Act protects "brock" since 1992 hence the population is growing steadily. As data show this goes along with a continuously increasing of bovine Tuberculosis in cattle, alpacas, other domestic species and "brocks" of course.
Any average sett is occupied by a bigger family with a very well organised pecking order. There is one boss and a dominant sow the total size of the group may be up to a dozen or more. When youngsters move away they have to look out for their own habitat and territory. If they intrude occupied territories they sooner or later are expelled - sometimes after fierce rows. Where do they go to? And where does a diseased animal go to? There are farmyards with muckheaps, sheds and haystacks with mice and troughs with rests of grains or cereals offering shelter and easy food. In summer cattle drink from water troughs in the fields - in any dry summer spell an easy supply for badgers.
What when such a weakened or diseased brock - or a dead one - is detected by Pink Panther Toby cat or one of the pack of sheepdogs on the farm?
Bovine TB ( bTB ) as we know is a very chronic disease affecting various mammal species including people. The most common spreading is by exhaling including coughing for the lungs are "hosting" so called tubercles, which consist out of masses of bacteria either alive ( and therefore well infectious ) or digested by macrophages as defence of the immune system. Every tubercle is a focus of infection and can be an abscess of up to an inch size full of typical crumbly pus. When bacteria are swept via blood or lymph stream they may land in other organs like the kidneys, liver, intestine, saliva glands or skin, where identically after weeks pus can result. Therefore we speak of pulmonary, renal, liver, intestinal or skin TB. Urine of a badger with renal TB can contain 300’000 bacteria per ml. A badger may urinate 4 - 6 times a day some 30 - 80 ml each time. My calculator shows this rises to shedding per day of some 10 times the amount RBS topmanager Stephen Hester gets as bonus for last year earned with public cash ( 90 million germs ). A bit crazy maybe? For a new infection with bTB it would need some 100 - 500 bacteria only.
When badgers fight the risk of scratches and wounds is very high. In a healthy badger these heal out in due time. When bTB is involved it is different. The very slow multiplying bacteria will sooner or later cause smelly excretions, wild flesh and pus which might be infectious - permanently or temporarily. Wounds may be licked every now and then by the very badger or by his mates even. New infection is around the corner, but this time in the intestine.
If a sow with bTB has cubs - or any other sibling of the same sett has got TB - these youngsters may get infected in their very first weeks of life by her own mother. bTB causes a very slow death after suffering over months or even more than a year. Hell - or perhaps worse? What a life prospectus!
Animals with bTB should never be treated hence the slaughtering of some 40,000 head of cattle per year. Even vaccination ( with unreliable BCG ) cannot prevent that further bTB spreading occurs. Antibiotics are not practical for they would have to be applied in adequate daily individual dosage for several months, nota bene causing resistance of other germs in grand style. Contraceptives for various reasons are no option either.
People with bTB are treated with high doses of a combination of 3 different antibiotics over 6 or more months with full success never guaranteed….
Worldwide TB causes millions of victims every year; the main part of those are caused by the human strain Mycobacterium tuberculosis, but bTB ( Mycobacterium bovis ) is equally infectious and dangerous for people.
Dr U Zellweger
An open letter from the Swiss Vet, Dr. Ueli Zellweger, sent to warmwell.com July 21 2009
DEFRA and its TB Vaccine for Badgers and Cattle
The vaccine is called BCG which stands for Bacille CalmetteGuérin. This strain of bovine TB bacteria was found 88 years ago and has been the main one reproduced for vaccination ever since. It is common practice to cultivate virus and bacteria for a long time for after some 10 to 20 generations they tend to lose their power to infect but still may produce specific antibodies.
BCG is rather an uncommon type of vaccine. In most infections the infected body copes with production of a large amount of specific antibodies within a few days which protect against an infection becoming serious trouble and these antibodies can be traced for diagnosis. This is not so with Tuberculosis for 2 reasons:
Therefore the body' s defence against TB has to work by making an allergic type of reaction instead of antibodies, a reaction which is made use of when humans and cattle are skin tested for TB.
- TB bacteria need 12 to 18 hours to multiply ( E. Coli takes 20 minutes only).
- TB bacteria have a waxy coat - quite unusual in microbes - to which antibodies cannot attach themselves.
In the past BCG was used for millions of doses for healthy young babies and in some countries it is still administered to a certain extent. It does not prevent an infection but minimizes the risk of it turning into a serious generalised form.
BCG' s efficiency was never over 80% and new scientific papers say it is dubious to rely on it.
The way BCG should work in already diseased badgers (and cattle) is highly questionable, meaning it is much more likely to produce adverse reactions such as awaking existing "silent" or low scale Tuberculosis.
The Merck Veterinary Manual covering all aspects of Vet Medicine worldwide comments:
"The BCG vaccine, sometimes used to control TB in man, has proved to be poor at protecting most animal species, and inoculation often provokes a severe local granulomatous reaction."This is likely to be a quite hurtful process and the vaccination site itself might well end up as an abscess.
As seen in trials, one cannot trap more than 60% of all badgers roaming around. Therefore if 60 out of 100 badgers are vaccinated with a vaccine which is only efficient to a maximum of 50 - 80% ( in healthy animals! ) you end up with far less than 50 badgers with a rather dubious protection.
It is well known and common practice that if you do not succeed to vaccinate up to 95% of all animals of a target species, the long term positive effects in an area are likely to be pretty close to zero.
If BCG is used as planned by DEFRA there will be huge perturbation and stress for all badgers, high costs and risk that the whole project will backfire.
In the hot spots some 50 % or more of all badgers might carry the TB infection already increasing the risk of TB spreading when being vaccinated and according DEFRAs plans all badgers should get a booster vaccination every 12 months making things even worse.
Who will be liable when it all goes wrong?
Dr. Ueli Zellweger