Tuesday, January 19, 2010

bTB in Badgers.

While the debate rages about cattle / badgers and now alpacas and other companion animals and their involvement and exposure to the bacterium known as m.bovis, Dr. Zellweger has looked at the effect of the disease on badgers. In a short communication "What Happens In A Badger Sett With Bovine Tuberculosis? " he describes the effect and spread of the disease:
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.
Successive tweaks to the Protection of Badgers Act, have awarded this delightful animal cult status and its home a Grade 1 listing - with an inevitable knock-on effect transferred to Animal Health veterinarians' methods of control under section 10 of the Act. And the badger population, when assessed by members of the Mammal Society increased by 77 per cent over the decade 1987- 97, as Dr. Zellweger points out:
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?

A description of the effects of this disease, and opportunities for its spread:
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 flow systems, 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!
And on the 'treatment' of bTB in animals?

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. Zellweger ends this piece warning "England beware!"


Anonymous said...

There are a few inaccuracies in this post.
One of them being the amount of territory used by badgers.
In Devon the average area for each social group is between 60 and 80 acres.
In places like Scotland where food is scarcer, the badgers range much further, and live in smaller groups.
bTB is actually quite a rare disease in the human, the most prolific form in the human, is the human form of the disease.
I have had Tb, the avian form which is so rare it is said not to affect humans, I would not have been surprised if it had been bTb that I caught,because of my interaction with the badgers here, but I have never caught it, even though the Dr says I would if the badgers here had it,as I am susceptible.
I still think we should test all cattle before they leave the farm to go to market to be sold on, or when they are sold privately, this would stop farm to farm transmission.
It seems to me that the badger has built up a good degree of immunity to this disease, considering the way they live, you would have expected an illness like this to have had devastating affects otherwise.

Matthew said...

Anon 10.34.

Agree that territory is variable, and depends on available food source. For instance, Woodchester Park's feeding stations would have a direct effect on how far groups had to range. But as population density increases, and food source is finite, where do they go? One of Woodchester's radio collared female badgers travelled 21 miles, to Bristol docks, and returned.

You say:
"I still think we should test all cattle before they leave the farm to go to market to be sold on, or when they are sold privately, this would stop farm to farm transmission."
Cattle moving in this way in all annual and two year testing regimes are pre movement tested before any movement. But cattle are pretty non-infectious, when regularly tested. And even in cattle with lesions where bacteria can be isolated, it is difficult to cause onward transmission in the field.(See postings describing Irish cattle/cattle trials, and the recent Pathman Project ,where all samples [over a thousand] were negative for onward transmission, even from 32 cattle with lung lesions.)

"It seems to me that the badger has built up a good degree of immunity to this disease, considering the way they live, you would have expected an illness like this to have had devastating affects otherwise."

Do not confuse immunity with the ability to wall up the disease, or live perfectly well while shedding bacteria. The two are quite different.

The badger is not 'immune' from TB but is able to live with it, maintain body weight and bear cubs, while shedding TB bacteria from highly infectious lesions. Thus it is a most successful host.

Badger lesions may wall up from time to time too, with possibly just two or three individuals within a group shedding at any one time, but the disease rippling through the group in waves.

But eventually, the disease will overcome them due to age, other bacterial or parasitic stress, or vis bite wounding. They then become what is known as 'super excreters', spilling bacteria from multiple lesions within or over their bodies. Some of the pm photos on the site give some indication of their suffering, prior to death. And they are 'devastating', as well as being highly infectious.

At this point the group will usually exclude them. Kick them out, and it is these 'dispersers' which cause the most havoc to our cattle herds and often seek shelter in, or near farm buildings.

Anonymous said...

D E F R A – Deliberately ignoring PCR

Speaking of the strangely ignored PCR technology - that is ignored for FMD - and bTB that is – there are a number of YouTube ‘PCR Songs’ the best one – I think is based on the song ‘One World’ (I’m a bit out of my depth here)

The two links are as follows:



The first is without subtitles the second is with

Note: At 1.500 feet above sea level my broadband exist but is slowish – so I initially get a ‘jerky’ version – on a second play – it plays fine!

Needless to say the first has had some 639,337 views worldwide – which indicates the state of acceptance within the USA and worldwide of PCR technology (excepting of course – DEFRA !!! )

It’s possible to embed the YouTube video in this bTB Blog but it’s a risk I’ll leave to management.

Otherwise google with 'BioRad PCR song' that should find it!


Peter Brady

Matthew said...

Thanks Peter. Can't embed anything anywhere, anytime at the moment. Main grey box, with all North's magic tricks to show seamless links has died. It's awaiting data recovery and until that happens, no tools or templates.
Agree PCR would be useful; it would also leave Defra no wriggle room and that is the problem.

badgerfan said...

the origin of the bacterium is in
farm slurry and cannot be blamed upon badgers

Matthew said...

Badgerfan said:
"the origin of the bacterium is in
farm slurry and cannot be blamed upon badgers."

When a herd that has not purchased cattle, does not share muck spreading equipment and has no cattle neighbours goes under almost continuous restriction, where does TB come from? The tooth fairy?

The majority of lesions found in cattle are in the throat, upper respiratory or head glands, indicating transmission from sniffing or ingesting it.
They don't eat slurry.

And farming operations which utilise the nutrients in f/y manure or slurry, are practised to encourage grass or crop growth, not to plaster over a mature grown crop.

To be passed into slurry, open TB lesions would have to be in the gastric tract, rumen, bowel or kidneys. (Which in badgers they often are, particularly if disease fulminates from bite wounding via the bloodstream.)

We are 'badger fans' too - of healthy ones. Delightful animals.

George said...

The potential problem of bTb being present in slurry was addressed by MAFF (now Defra) in the 1970s and in Ireland a little later. A great deal of time and energy (and public money) was spent in cleaning up reactor farms to prevent re-infection of the cattle with TB. The farmers loved it – their farms had never been so clean. It didn’t work, though and TB went on as before.

John H. said...

"To be passed into slurry, open TB lesions would have to be in the gastric tract, rumen, bowel or kidneys."

Not sure that's accurate. Slurry contains mucus and discharges from all orifii of cattle etc. It and dirty water are also applied in aerosol form which is a particularly virulent infection path. In Germany slurry has to have a high PH to kill the Bov TB bug, why don't we do the same? then this area could be excluded. Trouble with the Irish figures is that they wished to prove something and the practices don't seem to have the approval of an independant scientific body. Wish I knew what caused the problem. I am pretty sure though that the Badger cull is a bit of a red herring and that until farming practices improve little progress will be made.