Home Page

Bovine TB and human health

 Added by  Sally
 20 Jul 2010, 5:27 PM

Professor David Torgerson, and academic at York University and co-author of the report 'Public Health and Bovine Tuberculosis - What's All the Fuss About' has been speaking to the Yorkshire Post. He says it would be cheaper to contain the disease, using vaccines, even if that meant giving up some exports into the rest of Europe. Professor Torgerson says the case for trying to eliminate bTB is based on out-of-date fears of transmission to humans. The risk was more or less eliminated by universal pasteurisation of milk and the government is wasting £100 million a year which would be better spent on worse public health threats.. The main risk of transmission of bovine TB to humans was more or less eliminated years ago, by pasteurisation of milk.
'The UK resists vaccination because vaccination interferes with the standard European skin test, which certifies a herd TB-free. But we could get dispensation to vaccinate', said Professor Torgerson. It might mean losing the right to export live cattle to the rest of the EU. But that would cost less than the £100 million a year currently being paid out for testing and culling cattle and compensating farmers.
The Torgersons' report says there is no veterinary case for instantly culling all TB reactors. Most would be ready for the slaughterhouse, at the end of their careers, before they were ever seriously ill anyway. In other countries, animals come through the illness and herds develop resistance to it. And they sell beef to the UK.
Professor Torgerson told the Yorkshire Post: “As far as I can see, Defra has never done a full cost-benefit analysis of its policy and it needs to. It is difficult to see what the benefits are. But there is now a big vested interest in the system. Vets, for example, get quite a lot of income from it.”

Some interesting comments below from Professor Paul Torgorson, co-author of the excellent paper 'Public Health and Bovine TB, what's all the fuss about?'.
There has NEVER in the UK been a verified case of human bTB caused by eating beef. DEFRA knows this which is why they are happy to sell on the carcasses to recover costs and why bTB cattle are not condemned fro human consumption.
Milk is the vehicle of transmission to humans from cattle, hence why pasteurization of milk alone had virtually eliminated the disease in humans. When ever there is chance to give the zoonotic aspect of bTB a bit of exagerated publicity, it is done. Well you have to have some justification for spending £100 million a year. And all the stuff about for every case there are many more infected but asymptomatic is just speculation. There is no evidence for that....
If this disease (bovine TB) is so dangerous, that the government spends £100 million per year and wants to kill large numbers of badgers, then why is the government allowing it in the food chain?
The threat to human health of bovine TB
In a recent article published in the Independent, the UK's Chief Vet warned that without badger culling, there could be a serious threat to human health by increasing levels of human tuberculosis caused by the bacteria causing bovine tuberculosis. This statement is not supported by the evidence. Whilst bovine tuberculosis is a zoonosis (a disease that can be transmitted from animals to man), the way in which it is transmitted is virtually entirely food borne through milk. Providing milk is pasteurized before consumption there is a very low risk of transmission to humans, regardless of the amount of disease in cattle, wildlife or indeed cats and dogs. This is well recognised which is why there are no restrictions placed on infected farms in supplying (pasteurized) milk. Infected cattle which are slaughtered are not condemned as unfit for human consumption and indeed enter the human food chain. Even in the 1930s when perhaps 2000 or more people were dying each year of bovine tuberculosis, the primary lesion in humans was nearly always associated with the gastrointestinal tract due to the consumption of raw milk. Infection by other means was extremely rare. This was when perhaps 40% of British dairy cattle were infected with bovine tuberculosis. The high incidence of disease in humans was the original motivation for the control of tuberculosis in cattle, but the near universal pasteurization of milk has solved the public health problem. The latest figures in the UK indicate 8314 cases of human tuberculosis in 2011, of which just 37 were caused by bovine tuberculosis Even with the massive epidemic in cattle, virtually all human cases of bovine tuberculosis are either in old people, who were infected when young before universal pasteurization of milk, or in immigrants. And the diagnostic test used for surveillance in cattle only detects approximately 80% of cases. Thus there are many thousands of infected cattle in the UK, not being detected, but clearly not infecting humans.
Due partly to the inability to eliminate this disease from cattle in the UK and EU legislation that demands an elimination programme, the original aims of the programme have been lost. Effectively, the UK tax payer is spending £100 million per year on an animal health issue. This compares to approximately £40 million per year the NHS spends on treating the 8000 cases of human tuberculosis. Whilst farmers are rightly concerned about the impact of bovine tuberculosis on their enterprises, it is not the direct costs of the disease that are causing the problem (i.e. reduced productivity due to diseased animals), but the legal obligation of having a bovine tuberculosis control programme. As it is the programme, not the disease that is the root cause of the problem it is essentially a man made issue. DEFRA's Chief Scientific Officer asks those that oppose the cull to suggest an alternative. The UK Government should negotiate with their EU partners to obtain a derogation allowing a different approach that does not entail the unnecessary slaughter tens of thousands of cattle, farming enterprises being severely restricted and the pointless destruction of British wildlife. Vaccination of cattle, presently illegal, has an efficacy of approximately 60% whilst badger culling has an estimated efficacy of just 16%.
The Times ran a report 'Doctor warns of rising threat to humans from animals infected with bovine TB' in a recent edition under Health News (http://www.thetimes.co.uk/tto/health/news/article3881497.ece). In an email today Prof P Torgerson commented as follows.
The article says 'More than 20 young British men and women have been infected with potentially fatal bovine tuberculosis, and a specialist warned yesterday that unless it is brought under control in wildife, many more people could be at risk.' However, this is NOT ACCORDING TO PHE (see below).
The article states 'Badgers are being culled in the West Country to try to reduce the spread of the disease in cattle, but the danger to human health has been less well documented.' It IS documented - the danger is vanishingly small.
It continues 'Official figures, obtained by The Times, show a continuing threat to people, with a sharp increase in recorded infections since screening improved. Experts do not know whether the rise has been caused by more people catching it or because of better detection.' Again not according to PHE (see below).
The report continues saying, 'Professor Peter Davies, consultant physician at Liverpool Heart and Chest Hospital, said: “The more TB there is in the world the more the chances are that it’s going to spread. This is why we are trying to control TB in cows and other animals. There have been cases in which pets and humans have been infected with the same strain. One possible explanation for the increase is that there is more transmission from wildlife to humans.” ' HOWEVER, the number of cases of bTB in cats and dogs is small and DECREASING according to DEFRA's figures. The numbers of cases of bTB in cats peaked in 2010 with just 26 notified cases. This has decreased to only 9 in 2012. Likewise in dogs, the peak was in 2009 with just 3 cases, with just 1 case in 2012. In many years there were no cases reported in dogs. Thus domestic pets rarely have bTB and hence very rarely have any opportunity to transmit to humans. In an article in the Telegraph, the sensational headline was "Cats being infected with TB could be risk to owners, vets warn" See:http://www.telegraph.co.uk/health/petshealth/10150363/Cats-being-infected-with-TB-could-be-risk-to-owners-vets-warn.html However when you read the article it states: "One of the world's formost experts on feline TB (Prof Danielle Gunn-Moore) says that she had never seen an infection passed onto a human and so believes the risk to be extremely low". It seems the vested interests in bTB control and badger killing always spin missinformation to keep the public missinformed and hence on the side of killing wildlife....
It goes on to say, 'In 2004, the Chief Medical Officer imposed an action plan to stop TB. This declared that “if tuberculosis is being controlled successfully”, there should be a fall in cases of bovine TB involving under-35s born in the UK.' Yes but when you do not have any cases in the under 35s, you cannot get a fall.
It continues, 'The statistics suggest that Britain has failed to get the disease under control. Only five cases in British-born people under 35 had been recorded for the entire period 2000-2005. Public Health England (PHE) said that there had been one or two cases per year in such people for most of the past decade and fewer than five cases in any year but declined to break down the figures. However, the indications are that it missed the target to reduce cases.' Exactly - just one or two cases. What is the target - £100 million per year by DEFRA to get it down to zero. How many hospitals could you build with that money and save many other lives?
It continues, 'PHE said that there were 23 bovine TB infections in British-born people under the age of 45 between 2005 and 2012. Ibrahim Abubakar, of the TB section at the Centre for Infectious Disease Surveillance and Control, said that it was “difficult to draw any conclusion about trends”.' Exactly, there is no trend - its just a horizonatl line close to 0.
It continues, 'Traditionally, most people who get bovine TB have been elderly men and women who drank unpasteurised milk in their childhoods'. Or immigrants and is still the case.
It continues, 'Total recorded cases in humans soared to 104 in the period 2010-2012, compared with 66 in the previous three-year period, a rise of 58 per cent. The increase happened after the peak of the illness in cattle in 2008 but also after a change in detection methods.' Change in detection methods can increase (or decrease) the apparent number of cases. But also it depends on who has the disease. As PHE England state, only 1 or 2 possible cases in British born under 35. Also there was a surge in immigration in the last decade and that will take several years to feed through into the figures. Indeed most cases of human TB (M tuberculosis as opposed to M bovis) are also in immigrants, usually from poor countries like India (According to the PHE report over 1800 cases of TB were in people originating from India). Lots of cows in India, lots of unpasteurized milk drunk by Indians....
It reports that, Dianne Summers caught bovine TB from her herd of alpacas and now has a hole in her lung. She was unable even to lift a bale of hay and now has breathing difficulties. “It has absolutely changed my life,” she said yesterday.' She may have been one of the few (1 or 2). And alpacas are very susceptible to bTB, so their owners might be at greater risk. But to missquote Winston Churchil....In the whole history of human conflict has so much been given (£ 100 million per year), by so many (60 million UK tax payers) for so few (the 1 or 2). If there is a percieved risk to livestock owners, vaccinate them with BCG (especially alpaca owners), that would be whole lot cheaper than endless rounds of killing cows, badgers and everything else....How many cancer patients are being deprived of expensive treatments because of the National Institute of Clinical Excellent sates that some drugs are too expensive and so cannot be used on the NHS.
It goes on to say, 'She has recently stopped drug treatment and is being closely monitored to see if she is free of the illness.' See she was cured, probably cost the NHS a few thousand. Unlike the cancer patients who are denied effective treatments that are too expensive.
And then it refers to, 'Elizabeth Yeomans, 67, was the leader of Bridgnorth council in Shropshire when bovine TB was diagnosed. It was blamed on unpasteurised milk she drank as a child. The infection lay dormant in her spine until activated by a fall two years ago.' Exactly - not contracted recently!
It says 'The Farmers Union of Wales is so concerned that it wrote to the Welsh Assembly asking for childhood innoculation to be reintroduced.' The only possible risk group for bTB are those in contact with infected animals, and then only a very small risk. Sure vaccinate them if they want it: BCG vaccine has a long and well tested history of use in humans. Certainly better than slaughtering all the cattle and badgers....
See report of Public Health England, 'Tuberculosis in the UK 2013 Report' published August 2013. It can be downloaded from: http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317139689583

When does bTB stop being a 'pressing health problem in the UK'? When Minister is asked precise question!
Parliamentary Questions - bTB & badger cull
Hansard 9 July 2013 : Column 118W
Bovine Tuberculosis: Milk
Paul Flynn: To ask the Secretary of State for Environment, Food and Rural Affairs how many incidents have been reported to his Department of milk infected by tuberculosis (TB) since May 2010; and for what reasons his Department bans the sale of milk known to be infected by TB. [163633]
9 July 2013 : Column 118W
Mr Heath: We are unaware of any incidents being reported of milk being infected by TB. The TB status of herds is assessed by live animal testing and I am advised by the Food Standards Agency (FSA), which has responsibility for food safety and hygiene matters, that the EU Food Hygiene Regulations state that milk from individual animals showing positive reaction to the TB test must not be used for human consumption. This restriction contributes to a series of controls which aim to minimise the food safety risk. In rare undetected TB cases, organisms of the bacterium that causes TB can be excreted in milk but are killed by pasteurisation.
This is well worth reading.
Coalition culls and zoonotic ontologies
Diseases which can pass between animals and humans (zoonoses) have been headline news several times in the last ten years. This paper looks at bovine tuberculosis (bTB) in the United Kingdom, which, although not a major health hazard for humans, has been problematic for farmers and the veterinary health institutions. At its current rate of spread, the disease will cost the authorities £1 billion in compensation to farmers for slaughtered animals and in administrative expenses over the next decade. The present Coalition government are planning to cull badgers in England because they are the principal wildlife reservoir of bTB and are said to pass infection to cattle. We argue in five stories that the heterogeneities of bTB help explain the difficulties in dealing with it. In our opinion the present reductive set of policies would be improved by taking this ontological multiplicity into account.
I share Prof Paul Torgerson's view 'bTB and public health: what's all the fuss about'. The human and bovine form are very similar and there are many parallels. The link at www.cdc.gov/tb/publications/factsheets/general/ltbiandactivetb.htm gives an excellent and clear summary which could, I think, apply equally as well for badgers and cattle. It confirms that only in a very small minority does the TB bacteria overcome the defenses of the immune system and begin to multiply, resulting in the progression from latent TB infection to TB disease. Interesting facts re latency (and remember ALL cattle testing positive are culled - most will not be diseased and the aim is to kill min 70% of all badgers in an area without testing - most of these will be healthy):
... not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and TB disease.
Persons with latent TB infection do not feel sick and do not have any symptoms. They are infected withM. tuberculosis, but do not have TB disease. The only sign of TB infection is a positive reaction to the tuberculin skin test or TB blood test. Persons with latent TB infection are not infectious and cannot spread TB infection to others.
Overall, without treatment, about 5 to 10% of infected persons will develop TB disease at some time in their lives. About half of those people who develop TB will do so within the first two years of infection.
The risk to public health is very low.
1. A review of the global incidence of human tuberculosis caused by bovine tuberculosis. Conclusion is very little, even in countries without a bTB control programme. 'Zoonotic Mycobacterium bovis-induced Tuberculosis in Humans', published paper dated 2013.
2. A paper reviewing human cases of bovine TB in the UK (published 2007) concluded there was no evidence of a spill over from cattle to humans. 'No increase in human cases of Mycobacterium bovis disease
despite resurgence of infections in cattle in the United Kingdom', published paper dated 2006.
3. First case of bTB confirmed as spilling over from cattle (but the only confirmed case to date). Since then there may have been 2-3 more cases. 'Mycobacterium bovis infection, United Kingdom', Mycobacterium bovis', published paper dated 2006.
4. Paper from Ireland that confirms same pattern there. Human bTB is reactivation of previously acquired infections many years ago (although that conclusion is somewhat buried in the small print). 'Mycobacterium bovis strains causing smear-positive Human Tuberculosis Southwest Ireland', published paper dated 2008.
Again, we ask, why all the fuss about bovine TB?
Comment from GP (email 30/6/13) re the current bTB in meat scandal:
'Thinking about it, a ban on this meat entering the food chain would hit Defra's coffers hard. They'd have to keep paying farmers full compensation for the animals but wouldn't be able to get any of that money back by selling the meat onto processors. Interesting!'
Well, there has been a flurry of news regarding the sale of reactor carcasses into the food chain. Of course those of you who visit our website will know this is old news but some interesting facts are emerging. The Food Standards Agency (FSA) has confirmed there are no known cases where TB has been transmitted through eating meat and the risk of infection from eating meat, even if raw or undercooked, remains extremely low. So, again we ask, why all this fuss about bovine TB.
Prof PT has confirmed that 'there has NEVER in the UK been a verified case of human bTB caused by eating beef. DEFRA knows this which is why they are happy to sell on the carcasses to recover costs and why bTB cattle are not condemned for human consumption.'
'Milk is the vehicle of transmission to humans from cattle, hence why pasteurization of milk alone had virtually eliminated the disease in humans. When ever there is chance to give the zoonotic aspect of bTB a bit of exagerated publicity, it is done. Well you have to have some justification for spending £100 million a year.'
'Zoonotic Mycobacterium bovis–induced Tuberculosis in Humans' (full version at: http://wwwnc.cdc.gov/eid/article/19/6/12-0543_article.htm)
Even in areas with no control re bovine TB disease incidence in humans is very low. Again we ask; 'Why all the fuss over Bovine TB'.
We aimed to estimate the global occurrence of zoonotic tuberculosis (TB) caused by Mycobacterium bovis or M. caprae infections in humans by performing a multilingual, systematic review and analysis of relevant scientific literature of the last 2 decades. Although information from many parts of the world was not available, data from 61 countries suggested a low global disease incidence. In regions outside Africa included in this study, overall median proportions of zoonotic TB of ≤1.4% in connection with overall TB incidence rates ≤71/100,000 population/year suggested low incidence rates. For countries of Africa included in the study, we multiplied the observed median proportion of zoonotic TB cases of 2.8% with the continental average overall TB incidence rate of 264/100,000 population/year, which resulted in a crude estimate of 7 zoonotic TB cases/100,000 population/year. These generally low incidence rates notwithstanding, available data indicated substantial consequences of this disease for some population groups and settings.
It is inevitable that increased bTB testing (necessitating handling cattle for two days each time), brings greater risks to human health than any risk of catching bTB.
We have been given details of the seven incident reports received by the Health and Safety Executive (HSE) involving injury as a result of bTB testing over the last few years. It is stressed that there may well be more as the search undertaken relied only on the use of the term 'TB'. In addition the HSE tends to deal only with employees - the self employed, we are told, are responsible for their own health and safety. Brief details are set out below.
There was no incident report for the Pembrokeshire farmer who died during TB testing earlier this year - because this case is still under investigation.
08/05/2009 a vet, whilst undertaking TB testing on a herd was pushing cow into crush from behind when another cow behind her kicked out causing lacerations.
19/05/2009 a vet - steer escaped during a TB test, charged and kicked right chest and shoulder.
19/06/2009 a vet - right arm, fracture to radius whilst reading TB test. He entered the pen where some cattle were being held and without warning one of the cattle kicked her right arm throwing her across the pen - she landed on her back.
11/04/2010 animal health officer, during TB testing a cow his arm was trapped between the animal and crush when he was trying stik a needle into the animal. - notes say possible broken are 'due to return to hospital to have an X Ray to determine whether or not it is broken'.
13/06/2011 farm worker kicked in abdomen during TB test.
'06/08/12 down as a major injury - he went to hospital. Farmer -'we were trying to put the cattle in the cattle crush ti do testing and one of the young heifers kicked out which made contact with the injured person on his back and he fell down. The heifer then tried to move away, on doing so it stood on the injured person's ankle.
31/01/2013 vet was undertaking TB test some cattle attempted to break out past the vet (herding them from the handling yard to shed where testing was taking place) who attempted to stop them and turn them around but he was knocked/fell to the ground and dislocated a shoulder.
Email from Prof PT dated 21.05/13 referring to the report 'Zoonotic Mycobacterium bovis– induced Tuberculosis in Humans " published in current edition of Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 19, No. 6.
He commented 'It basically says that the global impact to human health of bovine TB is pretty small everywhere (even where there is no control)'.
Interesting extract from the report - we still cannot understand why so much attention and money is directed at bovine TB as it is such an insignificant risk to human health these days:
'There is evidence to suggest that zoonotic TB accounted for a significant proportion of the TB cases in the Western world before the introduction of regular milk pasteurization programs (6,7). Currently, in high-income
countries, bovine TB is well controlled or eliminated in most areas, and cases of zoonotic TB are rarely seen (6,7). However, reservoirs of TB in wildlife populations have been linked to the persistence or increase of the incidence of bovine TB in some countries, most notably the United
Kingdom (UK) (6). The absence of zoonotic TB despite an upsurge in the incidence of bovine TB in the United Kingdom sparked a controversy over the large financial expenditures for disease control in cattle (6).'
6. Torgerson PR, Torgerson DJ. Public health and bovine tuberculosis:
what’s all the fuss about? Trends Microbiol. 2010;18:67–72.
7. Michel AL, Muller B, Van Helden PD. Mycobacterium bovis at the animal-human interface: a problem, or not? Vet Microbiol.
2010;140:371–81. http://dx.doi.org/10.1016/j.vetmic.2009.08.029
Is the Animal Health and Veterinary Laboratories Agency (AHVLA) a bigger threat re bTB than cattle? According to a recent report in Farmers Weekly (/www.fwi.co.uk/articles/02/05/2013/138877/hse-censures-ahvla-over-bovine-tb-samples.htm, the AHVLA has been censured for safety failings over its handling of active bovine TB samples.
The Health and Safety Executive (HSE) completed a Crown censure procedure against the Weybridge-based organisation following an investigation into the handling of samples containing Mycobacterium bovis (M. bovis) - the causative agent of bovine TB, which in some circumstances can be harmful to humans.
The HSE found that over a period of more than two years, between January 2009 and July 2011, an AHVLA laboratory at Starcross, Exeter, had failed to appropriately inactivate M. bovis in samples that were then sent to their Weybridge laboratory for genetic testing.
Employees at Weybridge, Surrey were put at serious risk because they handled the samples without suitable control measures believing they posed little risk.
Working with M. bovis in a regular laboratory in its live form can cause severe disease and this posed a potentially serious hazard to employees. It therefore requires specific containment measures in order to protect workers.
AHVLA chief executive Chris Hadkiss attended the censure at HSE's Basingstoke office on Monday (29 April) on behalf of the AHVLA to accept a number of failings linked to the handling and control of samples.
In doing so the agency has formally acknowledged there were health and safety failings. These include:
Standard operating procedures were not fit for purpose - they lacked clarity and detail, and did not take proper account of the equipment at Starcross used to inactivate M. bovis, or the experience of personnel at that laboratory
The wrong equipment was provided - the equipment provided to the staff at Starcross for the M. bovis inactivation procedure was not the right equipment for the task
Training for Starcross technicians was inadequate - personnel undertaking the M. bovis inactivation procedure received no formal training on the process
Effectiveness of the inactivation process was not monitored - personnel at Starcross did not routinely check that the inactivation process was working and that the M. bovis samples were safe to handle
Managers failed to resolve issues - some operators at Starcross raised concerns about the inactivation process and equipment, but no action was taken
Crown bodies such as AHVLA, an executive agency of DEFRA, must comply with the requirements of the Health and Safety at Work Act. However, they are excluded from the provisions for statutory enforcement, including prosecution and penalties.
A Crown censure is the formal recording of a decision by HSE that, but for the Crown immunity, the evidence of a Crown body's failure to comply with health and safety law would have been sufficient to provide a realistic prospect of conviction.
HM specialist inspector Keith Stephenson, HSE's lead investigator in this case, said: "HSE's investigation at AHVLA, which resulted in the Crown censure, identified several serious failings that led to the potential exposure of a number of AHVLA employees to M. bovis over a period of more than two years. Exposure to M. bovis can be a serious health hazard.
"The evidence brought to light by the HSE investigation would be sufficient to provide a realistic prospect of a court conviction against the agency. This censure is the maximum enforcement action that HSE can take and should serve to illustrate how seriously HSE take the failings that were identified at AHVLA."
The Crown censure proceedings relate to AHVLA's discharge of its duties as an employer under Section 2 of the Health and Safety at Work Act 1974.
An AHVLA spokesman said: "AHVLA accepts that it failed to take all reasonable steps to ensure the health, safety and welfare of its employees by failing to monitor the ongoing effectiveness of the M bovis heat inactivation process. As a result a small number of employees were potentially exposed to M bovis. Potentially affected staff have been health checked and there is no wider impact on public health.
"AHVLA has now undertaken a thorough review of its standard operating procedures, updating them where necessary. Employees have also been retrained in order to ensure that they work fully in accordance with those procedures."
Email from MR dated 12/03/13: (Note: the article referred to is not specifically about bovine TB but TB in general.)
It would interesting to see how speed of approval varies between medical (and commercial veterinary) developments ones, and Defra’s lame attempts.

Thought provoking article in the Independent yesterday (/www.independent.co.uk/life-style/health-and-families/health-news/new-mrsa-superbug-strain-found-in-uk-milk-supply-8431187. html) reproduced below. This is surely a more significant and potentially increasing health risk than bTB? I see that, like with the bacteria that causes bTB, pasteurization ensure the milk is safe for public consumption.
New MRSA superbug strain found in UK milk supply
Research reveals that antibiotic-resistant organisms are gaining a hold on dairy industry
A new strain of MRSA has been found in British milk, indicating that the superbug is spreading through the livestock population and poses a growing threat to human health.
The new strain, MRSA ST398, has been identified in seven samples of bulk milk from five different farms in England.
The discovery, from tests on 1,500 samples, indicates that antibiotic-resistant organisms are gaining an increasing hold in the dairy industry.
The disclosure comes amid growing concern over the use of modern antibiotics on British farms, driven by price pressure imposed by the big supermarket chains. Intensive farming with thousands of animals raised in cramped conditions means infections spread faster and the need for antibiotics is consequently greater.
Three classes of antibiotics rated as “critically important to human medicine” by the World Health Organisation – cephalosporins, fluoroquinolones and macrolides – have increased in use in the animal population by eightfold in the last decade.
The more antibiotics are used, the greater the likelihood that antibiotic-resistant bacteria, such as MRSA, will evolve.
Experts say there is no risk of MRSA infection to consumers of milk or dairy products so long as the milk is pasteurised. The risk comes from farmworkers, vets and abattoir workers, who may become infected through contact with livestock and transmit the bug to others.
The discovery was made by scientists from Cambridge University who first identified MRSA in milk in 2011. They say the latest finding of a different strain is worrying.
Mark Holmes, of the department of veterinary medicine, who led the study, published in Eurosurveillance, said: “This is definitely a worsening situation. In 2011 when we first found MRSA in farm animals, the Department of Environment, Food and Rural Affairs [Defra] initially didn’t believe it. They said we don’t have MRSA in the dairy industry in this country.”
“Now we definitely have MRSA in livestock. What is curious is that it has turned up in dairy cows when in other countries on the Continent it is principally in pigs. Could it be in pigs or poultry in this country? We don’t know.”
The MRSA superbug can cause serious infections in humans which are difficult to treat, require stronger antibiotics, and take longer to resolve. Human cases of infection with the new strain have been found in Scotland and northern England according to Defra, but no details are available.
Dr Holmes said supermarket pressure on farmers to hold down prices was leading to the overuse of antibiotics to prevent cattle getting mastitis, an infection of the udder, that might interrupt the milk supply.
“If farmers were not screwed into the ground by the supermarkets and allowed to get a fair price for their milk they would be able to use fewer antibiotics,” he said.
“Common sense tells us that anything we can do to reduce use of antibiotics will reduce the growth of resistant bugs. We want to wean our farmers off antibiotics and the only way we can do that is with better regulation.”
Vets in Norway and Denmark had much more limited prescribing powers than in the UK, he added.
The excellent, well researched and referenced report, 'Bovine TB and public health: what's all the fuss about" can now be downloaded from http://www.zora.uzh.ch/47412/
KH has emailed today referring to an interesting extract at www.alpacatb.com from Dianne Summers' account of illness - she contracted bTB from her alpacas. She said:
On 10 May I received a letter from H.P.A. in response to my constant requests asking why none of my contacts had been offered testing. The letter informed me that because I was culture positive but smear negative this meant I was not infectious to others and therefore none of my contacts would be offered tests. Only members of my family household would be offered: but as I live on my own this meant no one would be tested.
It is a relief to me and no doubt to my contacts that they were not at any risk nor were my own animals.
According to reports in Farmers Weekly Dianne Summers (Redruth, Cornwall), the person who has led the campaign regarding bovine TB and alpacas (she founded the Camelid TB Support & Research Group after losing one of her own alpacas to the disease almost four years ago), has contracted the disease herself. She was apparently diagnosed with human TB caused by Mycobacterium bovis last week, after doctors initially thought she was suffering from pneumonia. She is now taking a cocktail of drugs, including ethambutol, rifampicin, isoniazid and pyridoxine. Recovery is expected to take around nine months.
Dianne fell ill in February with symptoms of a severe common cold. Pneumonia was was initially suspected but later tests indicated she had contracted TB. She is waiting to find out if her disease is linked to her herd or to another as she has regularly visited alpaca herds as part of her campaign to help other owners.
Dianne lost her first alpaca in 2008. Seven further losses were confirmed in November 2009 and it is understood the herd is currently clear of the disease. We understand that bovine TB has affected around d 56 alpaca and llama herds in England and Wales as of 1 March 2012. However, Dianne says she believes bovine TB is more common in camelids in the UK than reports suggest. Testing is not routine for camelids. There are currently no movement restrictions for camelids either. They can be riddled with lesions but still look well.
According to the Health Protection Agency there were just 35 cases of human TB caused by the bovine form of TB in 2009, only 29 in 2008 and 28 in 2007. An agency spokesman said the risk of people contracting the disease from any livestock was 'very low', continuing with 'Human TB caused by Mycobacterium bovis counts for less than 1% of the total TB cases in the UK. It's a really tiny percentage".

For information on comparing bovine TB with the human form of TB see http://www.bovinetb.co.uk/article.php?article_id=106
Conclusions: This study highlighted a low BTB prevalence in sheep and goats despite intensive contact with cattle reactors.
TBLN in humans was caused entirely by M. tuberculosis, the human pathogen.
M. tuberculosis seems to circulate also in livestock but their role at the interface is unknown.
Full report at www.biomedcentral.com/content/pdf/1471-2334-11-318.pdf

Email from PT 10/10/11
But despite the lengthy story on the testing and the ins and outs, I do find some optimism from slide "the future" near the end. He concedes the lack of public health benefit and hence concedes bTB is just an animal disease and it is trade that is driving legislation. He even agrees that the inhalation risk of transmission from cattle to humans is very small. This is quite something....
But when the value of the trade is a small fraction of the cost of the "cure", then clearly the legislation needs to change....
The documents from a presentation 'Bovine TB Where Are We Now' held in Feb 2011 are interesting. http://www.rabdf.co.uk/DynamicContent/Documents/Carl%20Padgett%20Presentation%20College%20Lecturers%202011.pdf
The bits on the skin test (and other tests) are indeed interesting and much of info echoes that of the discussion paper by the think tank Rethink Bovine TB, 'Bovine TB, Time for a Rething' (www.rethinkbtb.org) , in particular with similar concerns regarding accuracy. This section should be read carefully. It clearly reveals just how imperfect the skin test is. Those delaying the implementation of cattle vaccination give the reason that vaccination is not effective enough - however, it could well be that it would be more effective bearing in mind the policy is currently based solely on an imperfect skin test. Of great concern is that towards the end of the presentation, when discussing cattle vaccination for bTB and need to change EU legislation it states there is 'little if any appetite for this' - giving dates as 2015, 2020 and 2025? If this is correct how could Defra have got it so wrong in their 2010 consultation papers?
It is suggested we learn from countries like Australia, New Zealand and the Americas - skin test is used as it was designed for - as a herd test so any reactors and the whole herd is slaughtered with long term stocking delays - never suggested for UK (thankfully).
Some contradiction - Outcomes of Human Exposure seems to be unnecessarily pessimistic (and, for some reason, compared with Ethiopia?) when much later (towards end of presentation under 'The Future') they ask 'where is the public good in controlling bTB?' and confirm risk to humans is low becuase of pasteurisation and 'little evidence of inhalation risk from cattle to humans'. Yet again we are not told why, with such low risks, bTB needs to be dealt with so much more rigidly than any other disease/zoonosis.
Information on dealing with wildlife reservoirs is confusing as appears to contradicts other scientific reports.
A few misleading phrases are clarified. Let's not forget that OTF means 'free to trade' - not necessarily bTB free. Sadly nothing in here about the terminology relating to the skin test and how many cattle are actually being killed needlessly because they have merely been exposed to the bacteria that causes bTB.
Interestingly looking at the graph 'Is bTB improving' which goes up to 2009 (I assume this is England and Wales), it shows it is declining from its peak, despite the number of tests increasing with WAG apparently reporting a 14% reduction in new incidents and 28% less animals slaughtered in first 10 monthsof 2010 10 months of 2010
Good summary from a post by a beef farmer at www.fwi.co.uk/community/forums/p/60717/189404.aspx#189404
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?
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.
Email from Prof PT 20/9/11
In the information you sent me, somewhere someone makes a point that only bTB is a chronic zoonosis which can result in life long infection of symptoms appearing many years after infection. This argument was used to suggest why bTB is such a priority.
However this is also not true. Other examples of "chronic" zoonoses that occur in the UK, create more damage to the health of the human population but are largely ignored. These include echinococcosis and (congenital) toxoplamosis. The former remains with the patient untill (s)he is treated whilst the latter is lifelong for the baby affected by it. Echinococcus can be totally eliminated if appropriate dog controls and treatments are introduced whilst toxoplasmosis could be amerliorated if some money was spend on developing suitable diagnostic tests in the food chain (meat). A carcass testing positive to toxoplasmosis could be frozen before it is consumed (freezing kills the parasite). This would effectively prevent a substantial number of the hundreds of congenital cases of toxoplasmosis that occur in the UK each year.
£100 million a year spend more appropriately could help prevent real carnage caused by other zoonoses....
(A recent paper published in 2011 reports on a Japanese woman who contracted echinococcosis whilst living in the UK, 'Case Report : A Case of Pulmonary and Hepatic Cystic Echinococcosis of CE1 Stage in a Healthy Japanese Female that Was Suspected to Have Been Acquired During Her Stay in the United Kingdom by Kiwamu Nakamura, Akira Ito , Satomi Yara, Shusaku Haranaga, Kenji Hibiya, Tsuneo Hirayasu, Yasuhito Sako and JiroFujita.)

Email from JB 19/9/11
I personally have no concerns about human tb rates, having looked at all the HPA stuff, and other zoonoses. Wouldn't be keen on a major rise in btb, with no controls at all in place because of the wildlife implications, but as far as I'm concerned vaccination should be on the table for all cattle (excluding live exports), and the money saved from the test and cull policy could go towards badger vaccination schemes and cattle (if so required). There might be a blip in tb rates while vaccination took effect on herds, but its much more sustainable to my mind
Email from Prof PT 19/9/11
The risk to humans of bTB would remain very small even if all controls were removed and there was a massive epidemic in cattle PROVIDING milk for human consumption is pasteurized. The evidence to support this comes from a series of studies in the 1930's (pre control, pre pasteurization, pre antibiotics). People with TB were institutionalised...there was a series of large (human) necropsy studies looking for the primary lesion in TB cases. In the cases of human TB (M. tuberculosis), many primary lesions were indeed in the lungs indicating aerosol spread. But in the case of M. bovis, virtually every cases had the primary lesions associated with the gastrointestinal tract, indicating foodborne (milk) transmission. This was when up to 40% of Brirtish cattle had TB. I reviewed this evidence in my article "Public health and bovine tuberculosis: what's all the fuss about?" and you can all get the details there. It is a common argument used that controls are preventing a massive human epidemic. In reality based on pre control human data, the TB programme in cattle is preventing nothing, as long as milk is pasteurized.

  [ 1 of 2 ] 2 Next Last  

Free Forum by ViArt Ltd