Wednesday, July 29, 2009

Infectivity - badgers.

When the word 'tuberculosis, is mentioned it is simplistic to suppose that infectivety is similar between species. In our posting below, we quoted the remarks of VLA personnel on the results of camelid postmortems thus:
.. the predominant distribution of tuberculous lesions in alpacas which they had postmortemed as "within the lungs and associated thoracic lymph nodes", which they say, is "similar to most TB cases diagnosed in British South American camelids." And go on to describe " a heavy concentration of thoracic mycobacterial infection" which indicates that the respiratory route is the most likely means of transmission between these animals in close contact. This effect they say "may well be enhanced when some of the lesions show pulmonary cavitation".
So how does tuberculosis in camelids compare with the disease in badgers or cattle? Buried in the labyrinth of information on this subject is a passage from earlier work, which describes relative infectivety in badgers and cattle;
Within an infected social group of badgers, only a limited proportion of them may be infected, and even fewer individuals may be excreting the bacteria due to the presence of open lesions leaking infected material. The badger can remain clinically normal for many years despite having severe lesions that produce infected material and will often excrete intermittently. The lungs and kidneys are most frequently affected, but infected bite wounds can result in new infections and can themselves excrete large quantities of infected pus into the environment.
And then the important bit:
Tuberculous lesions in badgers differ from those of humans and cattle in that there is little cellular reaction but massive numbers of tubercle bacilli are present that can contaminate the surroundings. Infected lactating sows are known to pass infection to their cubs, and this may be a major means of spreading infection within the sett. Disease does not spread rapidly between social groups unless there is a dispersal of the badgers or there are males fighting to protect their territories.
(Stuart F.A., and Wilesmith J.W. 1988. Tb in badgers: a review. Rev. Sci. Tech,,7(4),929-935.)
From that we assume the authors support local AHO postmortem results in that cattle lesions are generally pretty non-infectious even when open. And that in 'field' conditions (as opposed to shooting zillions of bacteria up the noses of young calves), cattle to cattle transmission is overstated, as we reported here from work done in Ireland.

But badger lesions are highly infectious without appearing large and open and will shed intermittently throughout the animals' life, eventually overwhelming the system and leading to them becoming 'super excreters'. Camelid lesions would appear to be both large, open - and highly charged.

The observations on badgers and cattle by Stuart and Wilesmith was published in 1988 Ten years later, the National Badger Survey, published in 1997 showed that the UK badger population had increased by 77% in the previous decade. No current figure is available for population density, and thus the opportunity for more 'territorial fighting'.

Tuesday, July 28, 2009

Transmission - alpacas

We are grateful for sight of this week's Veterinary Record, where a report investigates an outbreak of disease which appears to be the result of convoluted movements, undertaken by some of this country's alpacas.

We have touched on the thorny problem of tuberculosis and camelids before with an on-going breakdown in a herd of Cornish alpacas covered by Farmers Guardian.

The report was submitted by VLA staff at Starcross, Exeter and follows the fortunes of some Devon alpacas, sent to a herd in south-east England for mating, where they were mixed and stirred with alpacas from different parts of GB, there for the same purpose. All are subsequently dead, with we understand, some onwards transmission from this outbreak evidenced on the Devon farm. The spoligotype isolated from the Devon females was neither Devon nor West Sussex, but proved to be Shropshire. A female from Shropshire visited the stud over a similar time period, and she had subsequently died.

The report points out that there is little or no documentation on the transmission of tuberculosis between alpacas - but as we have said, if a scientist hasn't seen something, that does not mean it does not happen. The saga of this deadly triangle is described thus:
"Four adult females alpacas from a herd in Devon (A) visited a breeding herd in south-east England (B) from October to December 2008. The owner noticed clinical signs in two of these, including lethargy, weight loss and occasional coughing, four and eight weeks respectively after returning to herd A. The disease was progressive and despite treatment under veterinary supervision, both alpacas eventually died in May 2009."
The report describes clinical postmortem results, including extensive lung lesions, pulmonary cavitation and lesions on the kidney in one alpaca. M.bovis was cultured and identified as VLA type 35 or SBO134. (The part of Devon from which the alpaca came is usually home to badgers and spillover sentinel cattle hosting VLA type 11)
Searches of VLA's extensive database revealed that SBO 134 had been reported in a Shropshire alpaca (Herd C) which had presented with weight loss and respiratory disease over a period of three weeks, and which had died in February 2009. This animal had not been off the farm for 16 months, but another female from the herd had visited the stud farm in the south east (Herd B) in September 2008, and remained there until December, when it developed 'respiratory disease' and died. It was not postmortemed, although clinical signs were consistent with TB.

The Veterinary Record report is submitted by D.F Twomey and T.R. Crawshaw of Exeter VLA, who describe the predominant distribution of tuberculous lesions in alpacas which they had postmortemed as "within the lungs and associated thoracic lymph nodes", which they say, is "similar to most TB cases diagnosed in British South American camelids."

The illustration shows an camelid lung, with extensive necrosis and cavitation. The authors of the VR report consider that a "heavy concentration of thoracic mycobacterial infection" indicates that the respiratory route is the most likely means of transmission between these animals in close contact. This effect they say "may well be enhanced when some of the lesions show pulmonary cavitation".

In other words, camelids are very susceptible to TB, the disease advances extremely quickly, most lesions are found in the lungs and, unlike cattle lesions, these are pretty loaded with a 'heavy concentration' of bacteria, especially when 'pulmonary cavitation' occurs.

Control over this potential swamp of tuberculosis is non-forthcoming from Defra, who believe it to be 'a minor problem'. Camelids are outside the TB regulations in England, thus movement records, AHO entry to trace-back premises and herd restrictions may be considered 'voluntary'. Or kicked into the 'too difficult' box? And then there is the thorny question of a test. At the moment the intradermal skin test is the only test recognised to indicate TB free herds - of any animal, including camelids. No matter that it is 'meaningless' on camelids (Vet Record 2007.) Nevertheless, herds are exporting alpacas, being released from TB restriction (always assuming they have actually reported ill-health or deaths of their animals, and not buried the evidence) and tested or untested, offering mating services such as undertaken with such devastating results by the Devon herd described above, and exhibiting these delightful creatures within children's play areas in tourist attractions and agricultural shows.

The VR report concludes:
"These new TB cases provide evidence of spreading M.Bovis infection through uncontrolled movements of South American camelids between holdings, particularly those situated in recognised endemic TB regions." and they warn "The zoonotic risk to human contacts is also a serious consideration to those handling potentially infected animals".
That risk is ever thus, as we posted here.

Saturday, July 25, 2009

FCN - New report

The Farm Crisis Network , a charity which supports farmers in times of stress ( for whatever reason) has produced a report on the effect a TB breakdown has on the farmers caught up in it.

We covered some of the many 'advantages' of TB restriction in a very early post on this site, many of which are repeated in FCN's report. The pdf.document (Note - file size 1.12 MB) is called 'Stress and Loss' and contains the results of interviews with many farmers whose herds have experienced TB restrictions.

FCN carried out research on the impact of bovine TB on farming families in three TB hotspots. The results are contained in a 39 page document, inter spaced with quotes from the many farming families interviewed.
"The worst thing was that cows very close to calving had to be shot on farm. We could see the calves kicking inside as they died....I feel there is a constant dark cloud of uncertainty over me, causing stress, anxiety and fear. I feel weary, mentally and physically which results in pain in my body.....Financially it is very stressful. Cash flow is a huge problem. Having to keep animals when I would normally sell them puts more pressure on me, on my family, animal accommodation and feed costs. I don't know how long we can keep going...."

The interviews were carried out by FCN volunteers in three areas - West Wales, the South West and Worcestershire - all longstanding bovine TB hotspots which having experienced decades of Ministerial prevarication, just like Topsy, have grown.

In fact they now link up, in a river of red annual testing parishes, from Lands End heading northwards and westwards, (as Defra's 2008 Parish Testing Map shows.)

Defra are more than happy to pile on the cattle restrictions (and pile up the carcasses) but as one farmer interviewed remarked:
"[TB] restrictions change the nature of the business - we are 'dancing to others' tune' rather than managing our own business as we would wish to."
And by dancing to Defra's tunes on their non-control of environmental tuberculosis, we are all playing games with a most deadly of diseases.

Tuesday, July 21, 2009

Hansard - Vaccination update

As the long hot summer begins and MPs trot off with their buckets and spades for the longest recess on record, a raft of answers to Parliamentary Questions appeared, some of which dealt with vaccination of badgers.

The MP for part of the Cotswolds, Geoffrey Clinton-Brown was asking about Defra's Vaccine Deployment project. Questioned about the time scale, junior minister, ex fireman and member for Poplar and Canning Town
Jim Fitzpatrick replied that the six proposed area sign ups would be in phases.
".. to allow capacity to be built up and early lessons to be implemented. Therefore, during 2010, vaccination will be carried out in a lead demonstration area, where contractors will be trained, and 20 per cent. (20 km(2)) of the other five areas.

The project will be fully rolled out, in all the areas, by the third year (i.e. all areas will have been vaccinated by 2012). Once this initial phase has been completed vaccination across 100 per cent. of the areas will continue each year and each area will be vaccinated for at least five years."
So just a single area of the six starts in 2010, followed by others. When teams of contractors have been trained. Perhaps it wasn't such a good idea to pay all the experienced wildlife teams in 2006 after all?

The ever practical Mr. Clinton-Brown then asked how many vaccinations each badger would require. The answer is below.
We do not know how long the protection lasts but an annual vaccination campaign is consistent with published results that BCG protection lasts at least one year in animals. Safety data from the Badger Vaccine Study (BVS) on repeated annual vaccinations will be reported in the final report of the BVS which is expected in March 2010.
And on the subject of marking any candidate badgers vaccinated, the reply was thus:
The temporary marks on vaccinated badgers will last for at least several weeks, depending on weather conditions. This is so a marked badger re-trapped in any given trapping session can be released without further vaccination. There is no need for long-term marking as there is no detrimental effect if a badger is injected again in subsequent years.
Now, given the answer to Mr. Clinton-Brown's previous point on how often BCG needs to be administered, (it is expected to last at least one year) this answer would seem to be somewhat contradictory. Further questions sought information on costs (Defra don't know, they are working on it)and expected labour requirements (100sq km will employ 10 people in 5 teams of two people, for a single vaccination season) and BCG may have to adminstered annually. This really is not what our industry expected from its Ministry, particularly as we explained in our posting below, Defra are encouraging farmers outside the six trial areas, only one of which will be actioned in 2010, to sign up at their own expense.

And by 2014, GB will be slaughtering how many cattle per year?

Any talk of Defra rushly blindly into this, armed with more hope than expectation, is purely in our readers' imagination.

This post may contain nuts.

Monday, July 20, 2009

Defra on Vaccination

Defra appear to be wearing two hats. On the one hand their badger Vaccine Deployment Project, as described to veterinary personnel, uses phrases such as:
Not a silver bullet - a way of reducing risk: Another tool in the box - use with other measures, and Defra cite 'practical and legal difficulties.'
On timetable, badger vaccines are described as "2010 for an injectable" and at the very earliest, "2014 for oral." Problems envisaged include:
Expense and lack of farmer confidence ( now why would that be?
Practicality of trapping badgers, need to access land, vaccinating a wild animal and technical barriers to developing an oral bait.
The initial six areas aim to vaccinate badgers in endemically infected areas and will continue for five years. The 'trial' is completely funded by Defra and will be carried out by trained contractors. Participation is voluntary and farmers may withdraw if they want to. Protocol is described as 'flexible' as 'this is not a scientific trial'.

Defra officials say that "If vaccination reduces the level of disease in badgers it should reduce the risk to cattle."

Note our emphasis on the carefully crafted 'maybes' in that sentence and compare to what the farmers are told. And it gets better. On the thorny question of vaccinating badgers already infected with tuberculosis, Defra agree that it is a waste,
But it keeps it simple.; you can't identify an infected badger in the field, the field diagnostic tests are not good enough yet. And infected badgers don't look any different ( From what? A bite-wounded bag of bones should be pretty obvious. What happens to that one?? )

And on perturbation - the excuse-for-doing-nothing that Defra have used, when hiding behind John Bourne's skirts:
The deployment project will be a lot less disruptive and less stressful for badgers. (than what?) The only risk of perturbation would be if you try to remove badgers, and we are not going to do that.
Mmmmm. Didn't John Bourne's recent efforts in the RBCT Badger Dispersal Trial, cage trap a few badgers, leave them confined for a fair while - but then return to find a shed-load of empty cages or cages gone walkabout as 'activists' released the contents or moved them to 'safe houses'? And wasn't perturbation cited as the reason for the early years' of the RBCTs apparent increases in cattle TB? And is it not the sole reason for doing absolutely nothing about a reservoir of disease now back-spilling into many other species?

So how is trapping a wild badger (that is 'wild' as opposed to the Woodchester badger population, who view a baited cage as their Ritz self service bar), leaving it a few hours to stew, tipping the cage on its end to make sure the occupant has its backside in the air, jamming a pronged fork through the mesh to secure it, jabbing a (long) needle in its backside, painting it yellow and then releasing it, not 'disruptive or stressful' for wild badgers, and will neither cause stress related perturbation nor increase disease status from 'infected' to (highly) 'infectious' ?
(That question was rhetorical by the way)

But we digress. That presentation was for vets. And it crept along with a lot of hope, little certainty and an abiding prayer that it would not make things worse. Our European masters demand a tuberculosis eradication strategy, and hey, Defra have one.

But already the Defra spin machine has clanked into action, inviting farmers outside the six 'trial-that-isn't-scientific' areas to volunteer to vaccinate their badgers. Farmers Guardian has the story.
Briefly, vaccine will be available at between £12 - £20 per dose and licenses to use it from Natural England. The work will be contracted out to trained personnel who will bill the farmer and that cost is likely to be much higher than that of the vaccine. But an upbeat presentation used rather different phrases and tone from that which was delivered to vets. Defra officials:
... believe farmers elsewhere, particularly owners of high value pedigree herds, may also see the economic benefits of doing it themselves.
... are confident that vaccinating in the project areas will bring benefits in terms of cattle disease.

To be fair (and why should we be?) Defra's upbeat officials also accept their latest prevarications strategy could take a number of years to come through "as already infected badgers will survive for some time". Other pamphlets we have seen use 4/5 badger generations (that's 20 - 30 years), but Defra say "disease trends will be carefully monitored".
Good. We are sure the world is watching UK's 'disease trends' with interest..

Defra conclude:
Badger vaccination will not eliminate the risk but should reduce it and will not make things worse.

Well that's all right then. Some strategy. Some eradication programme.

Tuesday, July 14, 2009

Specific powers for Wales

The Welsh Assembly has issued a document in which they describe a more comprehensive approach to TB.
"Specific powers have already been granted in Wales for inspectors to enter land and obtain a warrant for the purpose of testing for disease. The Order applies to cattle, sheep and goats and all other ruminating animals (including camelids) and swine."
Defra (England) may like to take note.

Sunday, July 12, 2009

BCG - what it is, how it works.

We are most grateful to Swiss veterinary practitioner Dr. Ueli Zellweger, who offers a thumbnail sketch of BCG, the vaccine with which Defra hope to stem the tide of badgerTB (and thus cattle casualties, camelids, cats and dogs, goats, sheep and pigs) by injecting the product into badgers, which are likely to already have er, badgerTB.

Dr. Zellweger and many others are less than enthusiastic about Defra's plans, as we posted earlier. We quote Dr. Zellweger's short paper, in full.

"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 loose 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:
1. TB bacteria need 12 to 18 hours to multiply ( E. Coli takes 20 minutes only).
2. TB bacteria have a waxy coat – quite unusual in microbes – to which antibodies cannot attach themselves.

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.
We have pointed this out on numerous occasions, that 'reactors' to the skin test, both cattle and human, are 'reacting' not necessarily to active or infectious disease, but producing an 'allergic reaction' to exposure to the bacteria which causes disease. A serious, often fatal bacteria, which it must be stressed, has no place plastered in increasing quantities across our green and pleasant land.
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?
Taking a wild guess at any future 'culpability', not a career politician, that's for sure.

Friday, July 10, 2009

"You've killed a third of my herd unnecessarily"

Having lost over 60 cattle in the last couple of years, a SW pedigree beef breeder told a top Defra civil servant yesterday that the non-policy which she was following on badgerTB, was responsible for killing a third of his prize winning herd, unnecessarily.

Gordon Tully's herd of South Devon cattle had a severe TB breakdown in 2007 / 2008, which culminated in the loss of over 60 cattle. Yesterday at the Royal Show, Mr. Tully was able to give Katrina Williams, director of animal diseases at Defra, the benefit of his experience. Western Morning News
has the story.

BVA press release

The British Veterinary Association (BVA)has issued a press release which calls for "humane, targeted and managed culling in specific areas where badgers are regarded as a significant contributor to the persistent presence of bTB"

Nicky Paull, President of the BVA, said:
"Bovine TB has an unacceptable impact on animal health and welfare and has the potential to be a risk to public health. Yet the current strategy for dealing with it is inadequate."

Badger culling is necessary in certain circumstances to tackle the spread of bovine tuberculosis (bTB), according to the British Veterinary Association (BVA) and British Cattle Veterinary Association (BCVA).
"Veterinary surgeons take an active role in surveillance, diagnosis and treatment of disease and we know that the only way to control bTB is through simultaneous and coordinated measures across all susceptible species.
The BVA's policy also states that the current Government strategy for bTB control is inadequate and calls for simultaneous control measures in both cattle and badgers and other wildlife and susceptible farmed species.

Thursday, July 09, 2009

Sometimes we wonder

Defra's 'Farming link' magazine arrived today and in it was a piece on their badger vaccination plans, but also an absolute gem within the piece on 'Developments in Animal Health Research'.

The former describes how this voluntary 'trial', relying on a few summer months of cage trapping (efficacy 20 - 70 per cent) and vaccinating the cage's occupant with BCG - a vaccine of uncertain efficacy, ranging from 0 - 80per cent - may damp down, over several generations, tuberculosis in badgers. Farmers were lectured on efficacy of vaccines last year for a different problem, and if memory serves us correctly, the target for a successful vaccination programme was said to be at least 80 per cent of the candidates.
Do the maths on this proposed 'trial' - and then post Defra a shiny new battery for its departmental calculator.

The latter describes VLA's spoligotyping team venturing more deeply into tracking the movement of strains of TB, and suggesting (tentatively) that this is "usually as a result of cattle movements". We would accept that statement, if other known reservoirs of this disease were not freely moved around the country with no records whatsoever of their passage, and if cattle were not pre movement tested. But it should not be a foregone conclusion with unfettered movement of translocated badgers and other species now known to be particularly susceptible to TB, and more than capable of onwards transmission, both among themselves and to human beings..

But the paragraph which had us tearing our hair was dealing with the development of badger vaccines, first injectable and then orally. But it is then noted by the commentator:
"Of course, vaccinating badgers would be unnecessary if it were possible to give calves lifelong protection against disease".

If one accepts the modelled, contradictory and topsy turvy world of the ISG who are still peddling the '70% cattle' v. 30% badgers line, one could postulate why vaccinating badgers to protect cattle is thought by VLA to be necessary at all. But let that pass... As they are beavering away to produce a BCG vaccine which may or may not work, may or may not obtain licensing and may or may not make the disease worse in endemically infected candidate badgers, what the blazes would vaccinating calves do if badgers infected with tuberculosis are to be left to fester in an environment shared with so many other mammals?

Have they not spoken to their colleagues at VLA who process the increasing number of samples from diseased alpacas, llamas, cats and dogs, more cats and another dog, free range pigs, goats, sheep and deer? The majority of these have had no contact whatsoever with sentinel, tested slaughtered cattle, but are victims of increasing spillback from environmental contamination on a scale we have not experienced before. The level of infectivety sustained and spread within herds of some of these species, indicates the real possibility of a second or third reservoir of tuberculosis.

Is VLA's next 'research' project to develop BCG for all mammalian species (including human beings) so that tuberculous infected badgers can roam free?

Tuesday, July 07, 2009

A different attitude..

.. to TB problems within camelids is seen from the llama society, and we are pleased to post the following link to their site.

The Britsh Llama Society say that bTB is spreading out of control and that llamas are susceptible to bTB. They remind members that "an increasing number of llamas are being found to have bovine TB."
Although the mode of infection is as yet unknown, it is likely to be either llama to llama, cow to llama or badger to llama. This is very concerning especially as we, as an industry, do not have any workable systems in place to reduce the risk of infection.
The latter comment would, we think, refer to the lack of any statutory identification or 'movements' database, combined with lack of 'right of entry' for Animal Health Officers on contact or trace visits and a serious lack of a reliable test for TB in camelids.

The bulletin explains that "TB is not caused by the owners lack of knowledge or by bad management. If you have infected animals you should not be embarrassed or ashamed. Our llamas and your fellow members need you to stand up and talk openly about your particular situation. This is the only way that others can become educated about the problem, how to handle it and what our rights are as llama owners."

In stark contrast to the response we understand individual alpaca breeders have had when flagging up their own TB problems, the Llama Society end their TB piece thus:
Unless those affected tell me who you are, I have no way of knowing how many of our members are affected. Your information will be treated in the strictest confidence, and will be known only to those on the board who are actively involved. As a relatively small industry we are much stronger when we talk as one. I can only do this if all those affected as well as those who may be in a hot spot come together and define what is required.

The first step is to let me know in the strictest confidence if you are affected. Please get in touch even if you think I already know.

The contact numbers are HYPERLINK "" or call on 01737-823375. And the bulletin ends:
We, as representitives of the Camelid industry, can't go forward with this unless we know what you want. Those with infected herds know who you are. You have a duty to the greater livestock industry to eradicate bTB from your herds, to do this efficiently and effectively everyone needs to work together. Herds do recover from TB and there is light at the end of the tunnel. The future of llamas in the UK could be seriously damaged if we do not get to grips with this issue.

The bulletin was issued by Liz Butler, Vice Chairman BLS & Health & Welfare Representative of the British Llama Society.

Update on the terrier

VLA have cultured samples of the generalised bTB found at postmortem in this little chap. Results have come back positive for
m. bovis - the spoligotype being the one circulating in his local environment between tested, slaughtered, sentinel cattle and untested, free ranging (and sometime re-homed) badgers. Type 17.