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Wildlife Reservoirs, is the badger a costly distraction, a scapegoat ...?



 Added by  Thomas (Guest)
 22 Jul 2010, 6:43 PM


Prof John Bourne, who conducted the infamous ten year, government-funded study which showed that badger killing is a waste of time and money, recalled what he was told by a senior politician:
 
"Fine, John, we accept your science, but we have to offer farmers a carrot. And the only carrot we can possibly give them is culling badgers."
 
This strand on the forum deals mainly with the wildlife reservoirs involved in the bovine TB saga. In the UK this is, as we are probably all aware by now, believed to be mainly the badger. No other mammal has been studied in the UK as intensely as the badger so actually we don't really know just how other animals are implicated. In other countries different species are implicated. There are some anomalies too, including the example below.
 
Has anyone an explanation for the following!
 
According to last issue of Gwlad, Australia is now bTB free after 27 years of trying. We are told it has no wildlife reservoir. New Zealand is still aiming for eradication. It has a wildlife reservoir - possums - which are considered a pest species as not indigenous so are being culled - and vaccinated!
 
HOWEVER - possums ARE native to Australia and bTB was rife in country for years so - why are the Australian possums not a reservoir?

becky
http://www.scoop.co.nz/stories/SC1110/S00048/epa-annual-report-on-aerial-use-of-1080.htm
 
New Zealand are killing possums using the poison known as 1080. October saw the fourth annual report published by The Environmental Protection Authority (EPA). It covers aerial 1080 operations conducted in the year ended December 2010 and research carried out to July 2011.
 
It includes data gathered from mandatory post-operational reporting, from monitoring, and from reported incidents and public concerns.
 
There were 45 aerial operations in 2010, covering nearly 440,000 hectares.
 
In 2010, 34 incidents and complaints about aerial 1080 operations were reported to the EPA (17 in 2009). All were investigated and six instances of breaches of the regulatory controls due to operator practice were found.
 
Sixteen breaches of the law were caused by actions of members of the public, some of which had the potential to create unacceptable risk to people and the environment, the report says.
 
Ms Eng said the report shows there has been progress in the last four years through research, development of industry standards and better communication, but that there is still room for improvement, as operator breaches are still occurring.
 
"The EPA will continue to monitor the use of 1080 and provide information on how the industry is performing," Ms Eng said.

 
Sally
Good summary from a post by a beef farmer at www.fwi.co.uk/community/forums/p/60717/189404.aspx#189404
 
The only justification for turning our attention to other hosts of bTB would be if the effects of the disease itself was responsible for the death and ill-health of the majority of warm-blooded mammals in this country including our own species. But this is simply not the case, instead it is the current policy which poses the biggest threat.
 
If a diary cow has bTB, is her milk a threat to human health?
No, her milk is made safe by pasteurisation.
 
If a beef animal has bTB, is the meat a threat to human health?
No, meat inspectors will decide how much of the carcass is fit for consumption and cooking kills M. bovis anyway.
 
Is the welfare of cattle severely compromised by bTB?
No, the vast majority will be in sufficiently good health for their immune systems to cope with exposure to the infection and their relatively short lives, economically speaking, means clinical signs of the disease will be very rare.
 
Do we need to slaughter cattle for their own health and welfare?
No.
 
Do we need to slaughter cattle for the welfare of other susceptible hosts?
Humans - there is no evidence to support the argument that the welfare of humans is significantly threatened by bTB in this country because of advances in science resulting in all of the safeguards already mentioned above.
 
Wildife - there is no evidence to support the argument that the welfare of our wildife is threatened by bTB. On the contrary, our own eyes tell us that Mother Nature's system of 'survival of the fittest' is working very well.
 
So a change to the way in which we view bovine tuberculosis, ie. by recognising that the disease itself is no longer the serious threat that it once was, would allow us to manage the disease within each herd with little attention paid to other hosts, ie. the badger, in common with our approach to other serious infections which can cross the species barrier.
 
Sally
New group Badgers Friendly Farmers …… now on Twitter http://twitter.com/#!/badger_friendly
 
This twitter page was formed after several discussions between a
couple of beef farmers when they realised they shared similar views.
 
 
Their Statement:
We all agree urgent action is desperately needed to stop the wild fire spread of bovine TB, which is destroying the livelihoods of so many farmers. Each one of us I’m sure will have a different take on what should be happening, could be happening or is taking far too long to
happen. But we all as individual landowners have grave concerns about the Government’s proposed “big society” badger cull. We believe it has not been thoroughly thought through and has little, if any, scientific backing.
 
We cannot see any good will come from this. In fact it has the potential of making matters far worse on many levels.
 
We realise we are few in number and our voices are drowned out by the might of the National Farmers Union and, as such, have little if any chance of ever stopping this cull.
 
But what we can do is be conscientious objectors and not partake. So we vow not to apply for badger licences, not allow shooters to enter our land and not allow anyone to disturb or harm the badgers that reside there.
Many of us own land with fit and healthy badger populations and we’d very much like to keep it that way. So we promise that the food, products and services we produce and create are all Badger friendly because our badgers are safe. If you care to look at who @badger_friendly is following you can see who we are.
 
What other farmers and landowners choose to do is entirely up to them, best of luck to us all……….
 
becky
Email response from JB 17/9/11.
 
http://www.telegraph.co.uk/earth/earthnews/8647710/Badger-cull-to-start-in-pilot-areas.html
 
Over the next four years up to 90,000 badgers could be killed across the country. Each licence is issued to a group of farmers in an areas from 15 -35,000 hectares (150 to 350km2) where the majority of landowners want a cull to go ahead.
 
The cull has to be carried out over four years and more than 70% of the badgers in the area must be killed for it to work, although Natural England will insist the animals are not made extinct in any county.
Defra said between 1,000 and 1,500 badgers will be killed in each 15,000 hectare area.
 
http://www.viva.org.uk/mediareleases/display-letter-to-editor.php?articlepid=7
'call to snuff out half of britain's badgers ludicrous and scary'
From this you can guess between 95,000 and 175000 depending on who's 'guesstimate' on population you use. (No idea where NE got their 190,000 total population figure from, can't find it. The only ones I know of are 300,000 and 350,000, and they are probably pretty inaccurate). But they get their figures from the same source as above and are working on the fact that there are between 33 and 40 (according to NE this is possible in the current license proposal) areas identified. We don't know the size of all those areas obviously it could be between 150 and 350km2, but I think now they have set 350kim2 as their lowest limit?
 
If you go with 40 areas altogether including the two trial areas the total number of badgers estimated by the govt is 140,000. Assuming they are right, because density is very high in the south west. I guess it depends on whether they worked on local levels or national. SO 70% of that is 98000.
 
http://www.wildlifeonline.me.uk/european_badger.html
There's a nice summary on the above website of all things badger (If I had the time I'd be doing that myself, he really tries to cover everything and it saves me going through a load of papers for you!);
There are typically about 10 badgers per 100 ha in 'good' British badger territory (range: 2 to 300). According to Michael Clark's book Badgers, the smaller territories observed in badger clans from Gloucester were about 40 ha (100 acres), with the smallest being 15 ha (38 acres). Roughly 70 ha (175 acres) was more typical of southwest England, while in the low-density areas of Scotland, territories were around 180 ha (400 acres).
 
It looks to me like DEFRA have gone off that top line in red. ie 15000(ha)/100(ha) = 1500
 
So anyway, depending on the territory size, go roughly with 6 -8 (say 7) badgers per territory. Territory can be anything between 15-70, you're talking about 1 badger per 2.14ha-10ha areas. (average size of territory 40ha - 1 badger per 5.7ha). The lowest territory size there you can probably put down as an anomaly so bear that in mind but I'm no expert in the SW.
 
High density est- 15000ha / 2.14 = 7009 badgers
Average density est - 15000 / 5.7 = 2631.5 badgers
Low density est - 15000ha / 10 = 1500 badgers.
 
Following from that to achieve 70%:
High: 7009 x 70% = 4906
Ave: 2631.5 x 70% = 1842
Lowest: 1500 x 70% = 1050.
 
My maths may be way out (I'd like to hope not but you never know), but it seems to me the govt could be just a little low on their population estimates. Not massively, but it will vary.
 
That's for the 150km size. You change it to 350km (35000 ha) you're looking at;
High: 11448 (at 70%)
Ave: 4298
Lowest: 2450
For the one area.
 
If you take the lowest at 35km2 you are talking 98000 badgers in total (over the whole period assuming population is static) assuming a total of 40 areas. Mid range is 171920. Highest (I balk at this figure) 457920. Fortunately, there is no way that the highest potential density figure covers all of those areas, or even much of them. If that were the case, there'd be alot more badgers in the UK than we think! It will vary an awful lot in the SW as a whole never mind the rest of the UK. And its all guesswork....
 
What is playing on my mind is that due to persecution and large areas of moorland we have a much lower density in the north, and probably it's similar in the east midlands. We as a badger group really have no idea how many active badger setts there are in our county. We have 200+ sett records, but no way of checking them. There are probably a lot more setts, but we can't get on the land. At the same time, a lot of the setts we do get around are very heavily dug and baited, so clan size can be much smaller. I surveyed one site for a year, three setts were already dug when I started, one of them was dug at all 7 chambers (that 7 badgers down the drain). I knew there was at least one badger on the site, poor thing was moving from one sett to another on a daily basis just to keep an eye on its territory. I don't believe there were more than that. Clearly there was no badgers on adjoining land to join with. We just don't know basically how many setts are still active, even in our own database. If we don't know, I don't see how anyone else can guess. If no-one knows what the UK population is, how can we take a shotgun to the area with the most of them?
 
Another summary on figures here http://www.guardian.co.uk/environment/damian-carrington-blog/2011/jul/19/badger-cull-bovine-tb-spelman Lower than mine but again who really knows?
 
If I could just find out where NE gets its UK population estimate from....
 
But anywhere if you take the figures above (98-171k) it's most likely to be somewhere in between, possibly lower, not higher.
 
Trevor
If the cull goes ahead how many badgers will be killed in England and Wales?
 
Sally
Email from BH 16/9/11,
 
Our sheep do exactly the same thing with badger setts, it's to do with the sun warming up the bare earth works like a little heat matt for the sheep, where we have open badgers setts actually in the grass the sheep sneak under the electric fence we've put round and fall asleep in the entrances of the setts.
 
In fact this is the only way we lose lambs to badgers ... lost two this year.
The lamb falls asleep right at the entrance we think probably a pregnant sow - defensive of her territory woke up in the evening walked out found a white wooly thing on her doorstep eviscerated it.
 
You can always tell a lamb thats been killed by a badger to a lamb thats been killed by a fox, badger kills = lots of bloody, and lambs look like they were beside a bomb, fox kills are a lot cleaner.
 
At this point a lot of farmers would then shoot the badgers, we didn't we moved the lambs and sheep to a new field problem sorted :)
 
Sally
Watching Countryfile recently when Adam Henson did a piece on the badger, I noticed that when they were filming his farm he showed some film from his night camera which had captured his sheep at a badger set. This got me thinking again about other mammals. Looking at Adam's sheep that were obviously lying all around the badger set and presumably in contact with areas frequented by badgers (and perhaps badger urine?) why do sheep not contract bTB more often? The number of sheep found to have bTb is miniscule (only one case last year according to Defra) but no-one seems to know why as they may be more exposed to badgers than cattle are - or maybe it is not the badgers ... Perhaps sheep don't succumb to diease easily - which I find hard to believe ... Yet another example of how little is known about bTB ...
 
becky
Email from JK 15/9/11
 
The effects of the terrible 1080 poison are horrific – and especially when you take into account the collateral damage of unintended wildlife. Again, it’s a case of wildlife dying when problems closer to home are being ignored.
 
becky
According to a posting on Warmwell (www.warmwell.com) Aug 15 2011 it causes poisoned animals a slow and very nasty death. It is not currently banned in New Zealand or Australia.
 
On www.1080facts.co.nz 1080 attempts are made to justify the use of this poison.
 
There have been recent reports (www.stuff.co.nz/dominion-post/news/5446799/New-possum-poison-approved) of a new poison to kill the possums in New Zealand. The EPA has approved the application and a number of advantages have been cited, such as reduced secondary and tertiary poisoning of livestock and domestic animals associated with brodifacoum, 1080, diphacinone and pindone.
 
The poison, zinc phosphide, will target brush-tailed possums and apparently does not leave residues in venison for export or domestic consumption.
 
The EPA has imposed strict conditions on its use, including limiting it to trained and licensed operators.
 
A poison is designed to kill, No poisons are without their problems.
 
becky
www.scoop.co.nz/stories/SC1109/S00013/farmers-disgusted-at-aerial-1080-drop.htm This recent article tells us that farmers in New Zealand are disgusted that the Animal Health Board & the Department of Conservation have begun dropping the poison, 1080, on North & South Okarito Forests.
 
This was apparently permitted to go ahead even though the consent was issued for possum control only and DoC have widely advertised that they are targeting rats and stoats. 'This action flies in the face of the lengthy studies e.g. Wendy Ruscoe showing that some of the unexpected consequences of 1080 drops are the arrival of rat plagues, knowing that stoats are not attracted to the baits and seldom eat dead rats but prey switch from 6% birds in their diets to 67%'.
 
'Ignoring this is clearly a process of wilful blindness on behalf of the Department of Conservation and legalised ecocide by both them and the Animal Health Board, the belligerent bureaucratic juggernaut that poisons because it can. If the AHB put its poison money into meaningful farmer education, there would be no bovine TB'.
 
Sally
 
New Zealand was widely recognised as the world leader in TB management and WAG has made many references to its strategy in Gwlad. However, what has not been admitted is the growing opposition to the widespread use of poisons being used to kill possums but which are also affecting other species.
 
It has recently been reported that New Zealand taxpayers will pay $150 million in the five years to 2015 to fund the Government's share of killing possums and managing bovine tuberculosis. The taxpayers' contribution of $30m a year is on top of $45m a year from beef, dairy and deer farmers, and $6m from regional councils.
 
The funding would appear to be financing a revised National Pest Management Strategy, to eradicate the disease in possums and other wildlife from one quarter of New Zealand's vector risk areas. This was about 40 per cent of land area. The initial 1998 pest management strategy was aimed at the trade-oriented target of meeting international levels for 'official freedom' from TB - having only 0.2 per cent of deer and cattle herds infected in 2013 - a level which would prevent trade rivals using TB incidence as a basis for seeking non-tariff trade bans on NZ meat and milk exports. But in 2007 MPs were told that TB-infected possums, ferrets, and feral pigs and deer remained in nine million hectares of NZ - about a third of the country - and those animals would continue to infect farmed livestock until the disease was eradicated from wildlife.
 
In 2009, a plan was implemented over 40 years, proposing to eradicate TB from pest animals, starting with a 15-year stage to 2025: trial TB eradication from large selected areas of heavily-forested country through control operations over a five-year period involving annual ground control and four to five yearly aerial 1080 control operations.This would be followed by five years of intensive wildlife monitoring and herd testing to ensure the disease was eradicated. IT IS NOT KNOwN IF THIS WILL BE SUCCESSFUL as it goes on to say 'If large-scale eradication proved feasible, the AHB would progressively eliminate it from the rest of the country under a new pest management strategy from 2025, with nationwide eradication taking another 20 to 30 years'! If these projections are true, this is farcical and NZ should not be held up as a country whose example the UK should be following.
 
Main information from http://www.nzherald.co.nz/business/news/article.cfm?c_id=3&objectid=10692507
 
Sally
New Zealand is being upheld by WAG as an example to follow with regards to dealng with bovine TB. But ... have they really got it right! Friends returning from New Zealand recently commented about the number of warning signs indicating use of poison and dead carcasses strewn around, not just of possums, but other species too.
 
To kill the possum they use a poison known as 1080. It kills without discrimination and a lot of other species too are being poisoned. The United Future party has pledged to push for a ban on this poison. This has disappointed some farmers who are battling to deal with bTB in their herds and are apparently losing stock worth thousands of dollars. However, because the poison is killing a wide range of animals, not just possums, and is polluting streams and rivers, The United Future's leader, Peter Dunne, plans to negotiate a ban in the wake of next year's general election. He said the party would encourage other forms of pest control, including the greater use of traps, and support more scientific research to that end.
 
Source: http://www.radionz.co.nz/news/national/61765/1080-ban-would-jeopardise-tb-fight,-say-farmers
 
 
 
 
Sally
http://blogs.nature.com/news/thegreatbeyond/2010/11/bob_watson_faces_the_bourne_su.html
 
http://www.badgerall.com/blog/farmers-are-being-led-up-the-garden-path
 
Reports of meeting of top scientists 09/11/10 'Zoological Society Debate on Badger Culling'
 
Whilst the UK's top environmental scientist strongly defended government plans to cull there was an impassioned intervention from the floor by Professor Bourne, who chaired the Independent Science Group conducting the former Randomised Badger Culling Trials (RBCT). He said that whilst he found it reassuring that DEFRA had based their proposals on the RBCT they had stepped away from science in how they propose to implement the programme. He was very aware of the logistics involved in achieving 80% removal of badgers – it had involved dedicated teams working around the clock. To suggest farmers could do this was a ‘by guess and by God approach’. If they really intend to cull he said let the Government do it, spend a lot of money and accept that the returns won’t be great. He went on to say that he was distressed that DEFRA hadn’t had a coherent TB strategy over so many years and refuse to learn from the former eradication programme in this country in the 60s and from Australia’s experience. He called for an approach based on a ‘herd test’ leading to identification and quarantine of infected herds (for up to 2 years) – rather than the current inefficient individual animal testing. Without such stringent measures, he said, Australia made no progress – with it they made progress. He ended by saying that ‘farmers are being led up the garden path’ by current policy and practice.
 
 
Keith
Even Professor John Bourne, who co-ordinated the RBCT killing 'experiment', stated to the BBC 
. 'I think it is true to say the badger has been made a scapegoat,'
 
'... we conclude that badger culling cannot meaningfully contribute to the future control of cattle TB in Britain.' (ISG Final Report, 2007 The science that says a cull will not work (Prof Krebs) was actually set up for the Conservative government by Angela Browning MP in November 1996.
 
Sally
The following post is of interest from www.warmwell.com/2010fink.html 'I am still of the opinion that feeding stations with high dosage of triple antibiotics for say 6 months coordinated, could be worth a try. It would not be that expensive, but would need very good attention to detail. It would at least reduced the bacterial load in those wild animals that are a reservoir for infection and often excluded from the badger setts'. 
Email received January 7 2010 from Dr Colin Fink,
There is a problem with badgers highlighted to me by Professor Liz Wellington at Warwick, whose team have done the surveillance work. Evidently there will be a few badgers who are the high excreters of Mycobacterium bovis. They are ill and often excluded from the setts. The question which is difficult to answer is how many unaffected badgers are carrying the bacterium? They may remain healthy and not excrete particularly. We could decide to eliminate whole sett populations. If we do we would have to destroy and disinfect the setts as they will be re-colonised by other individuals and the Mycobacteria will still be there to infect the new population. It may be possible to both undertake sett elimination if the evidence of infection is available, and also treat geographically around the sett with triple antibiotic loaded bait (repeatedly). So those locally will at least have any infection reduced and carriage eliminated. It may also be possible to bait with contraceptive hormones so populations also naturally decline.
I do not think that any single policy is a panacea and we need to consider combined approaches, to reduce the carriage and excretion of organisms, minimise population pertubation, which creates stress and increases mycobacterial disease ( rather than carriage), by using selective sett culling and also consider in conjunction, both contraception and antibiotic baiting.
Any combined approach will need very careful policing and implementation. Surely that is a better investment than constantly killing herds of cattle and all that which goes into raising these animals?
We have no other alternative as vaccines are not available because the organism is not amenable, and we are losing herds of cattle, alpacas etc and increasing the organism load in the wild population at an alarming rate.
(Dr Colin Fink is Clinical Virologist & Hon. Senior Lecturer in Biological Sciences University of Warwick, and Company Medical Director, Micropathology Ltd Research and Diagnosis).
 
Comments received from Ruth by email 24/7/10
I was not previously aware that latent TB could be treated to prevent its reactivation at any time in future life, (unless reinfection takes place later (reinfection is documanted in humans and when opportunitiy for reinfection is high it commonly occurs)).  Latent TB can be treated by 9 months of ISONIAZID alone (and a shorter course for chemoprophylaxis after exposure), unless the infecting organism was already resisitant at the time of initial infection.  I believe this is what some camelid owners are doing for exposed camelids.  Both camelids and goats as species seem to be particularly susceptible to M bovis with progressive infection from which they die.
 
The infection rate in a confined space such as a social group or sett of badgers will be between 25 and 50% if comparable to humans, but genetics and species may make it higher or lower. The diagnosis of latent M bovis infection in badgers is not accurate in microbiological terms as yet and would be likely to be underestimated by any tests currently used on them.
 
If Isoniazid alone is put out for badgers then the actively infected badgers that eat it (one cannot exclude actively infected badgers from eating the bait) are likely to develop resistance and the M bovis shed will be resistant to isoniazid within weeks or months and infect other badgers with resistant M bovis, so that strategy won't work.
 
In humans active infection is treated with multiple antibiotics taken every day, isoniazid, rifampicin, pyrazinamide and ethambutol for example- 2 months on this combo, then depending on the culture, typing and sensitivity report, reducing to 3 for a further 4 months, but in the case of M bovis dropping pyrazinamide as M bovis is intrinsically resistant so that in M bovis 3 drug treatment is given for 9 months in total.  If the treatment is taken reliably then the person is cured of that M tuberculosis or M bovis infection.   For example elephants have been cured of M tuberculosis infection (they are only rarely infected with M bovis). (It is likely to be unaffordable for farmers to treat cattle) 
 
As you have probably heard multiple drug resistant and even extremely drug resistant M tuberculosis is now circulating in humans because they have not taken the full course of treatment.  These organisms can infect hitherto uninfected individuals and may be untreatable and lead to death or indefinite confinement if excretion cannot be stopped by surgical removal of infected lung.
 
For this reason I have argued against Colin Fink's idea of putting out triple antibiotic therapy bait for badgers hitherto.
 
However if there is essentially a reservoir of M bovis in badgers and cattle (and deer, camelids, cats etc) that humans almost never get maybe such an approach together with vaccination of badgers and birth control of badgers / population reduction would not be such a bad idea afterall.  Vaccination of cattle and testing and culling of infected cattle would have to continue to get rid of M bovis infection.  The cycles of infection would be broken, stopping reinfection of either badgers or cattle from the other species.
 
The reasoning would be
1  The closely observed sett would thus have triple drug treatment of the active and latent infected badgers if this was continued for at least 9 months hopefully eliminating infection from that sett.
2  All the setts in possible contact with each other would have to be treated simultaneously.
3  If multiple drug resistant M bovis developed (part of the monitoring) then that group of badgers would have to be culled as it could spread to other badger setts.  If such resistant M bovis infected a human which would be very unlikely that human is anyway very unlikely to pass it on to another human (though this has been recorded on rare occasion).  An epidemic of resistant M bovis in humans would not happen as it is essentially a preventable zoonosis (by pasteurisation of milk).
4  Having small numbers of closley observed and monitored setts would necessitate reduction in the badger population, at least of infected setts (ie latrine PCR positive for M bovis)
5  However vaccination with the live attenuated vaccine BCG would not be successful if treatment was being given simultaneously (vaccine is killed by treatment), so perhaps vaccination could follow the treatment in infected areas.
6  Birth control would be a way of reducing the population without the suffering of culling, the consternation of animal rights people, and be ulikely to perturb the badger society.
 
A question that I couldn't answer is whether it is possible to get the badgers to eat sufficient of the bait daily for 9 months so that the triple drug therapy had an opportunity to work.  In a way the badgers of the treated setts would have to be trained.  Would some eat so much they would poison themselves?
 
A method such as this could only be used in a developed country and would have to have the full co-operation of people.
 
I have corresponded with badger trust people in Wales and they are implaccably against population control of badgers by birth control methods.
 
I also suspect that DEFRA and the HPA would never countenance the treatment of badgers with triple drug therapy.  The EU rules would be a problem I am sure. 
 
In conclusion I do think Colin's idea is more interesting and possible than I thought as a first reaction.  People have no difficulty getting badgers to come to their gardens and eat peanuts for example. 
 
The problem is that to do anything other than killing is obstructed and slowed for lots of different reasons, rules, bureaucracy and scientific difficulties, so that nothing can be given a try.  Why should the Irish be at the stage of trialling oral vaccine for badgers and yet we be 5 years away from it?
 
 
 
 
 
Sally
Dr Dan Forman (conservation and ecology) has said that the behaviour of possums in New Zealand (alien spp) is very different to those in Australia (native spp). The epidemiology of diseases is context and locally specific. What happens in the UK is likely to be very different to that which occurs in New Zealand / Australia, between Australia and New Zealand, New Zealand and S America etc – this is because the environments, ecology, animal spp, their densities, behaviour, landscape management and land use all differ significantly. Quite why no possum has succumbed to bTB infection (even as a non-aggressive form of TB) is not currently clear. Possums are an easy option to cull in New Zealand as they aren’t native and the national pride is to restore the ecology of New Zealand back to pre-non-native species introduction status. In Australia this would be a very different issue and one not tested in courts over there yet!
 
Sally
 
 
Also, Ruth, in her email dated 21 July 2010 says, 'I don't know why the Australian brush tailed possums were not a reservoir in Australia but they weren't. The climate, the distribution of possums etc are very different in Australia to NZ. The problem with the introduced animals to New Zealand is the extraordinary way in which they have thrived- grown larger, bred more and of course have no natural predators or diseases. It may be there are more possums in NZ than Australia, and their density is also greater etc. The climate is milder and reliably wetter, again features that may favour the survival of M bovis in the environment. They are not sparing vaccinated possums but are seeking to kill all possums in NZ. The trouble is there are 20 million of them!'
 
We were sent this link to a more detailed report on this very subject. http://www.wildlifehealth.org.au/AWHN_Admin/ManageWebsite%5CFactSheets%5CUploadedFiles/119/Possums%20and%20TB%20in%20Australia%201%20Apr%202010%20%20(1.1).pdf
 
On 22 July, Ruth, after reading the report in the link above, commented, by email, 'they seem rather certain the organism survived for 2 or 3 weeks in dens but only 2 days on pasture. I expect that is from swabbing and culture. Prof Elizabeth Wellington from Warwick University did a sophisticated PCR analysis specific not only for M bovis but also for metabolic competence and presumed viability that suggests that in Ireland in favourable conditions on pasture, damp and shaded, the organism may be viable fo 6 months.
 
Poor NZ. I saw they are looking at sterilising vaccines for possums and that may be the way to get the population down so they can poison the remaining few. The possum is described as a folivore and if it hasn't eaten the native NZ fauna it destroys the flora, so depriving the NZ fauna and destroying the biodiversity of the ecosystem. Also I read that possums established in the wild in NZ in the mid 19th century so it is interesting that they have been implicated as M bovis reservoirs only recently, perhaps M bovis infection in cattle became widespread shortly before the possum became a reservoir through infection from cattle. I don't know if NZ has variety in the spoligotypes and genotypes of M bovis as we do (badgers largely coinciding with the same in cattle in the same area). Interestingly our efforts at M bovis elimination from cattle has narrowed the genetic variation in current M bovis strains- old humans who reactivate do so with strains not currently present in cattle.'
 

 

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