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Archive for April, 2020

There’s nothing unusual about disagreements amongst scientists – indeed it is that exchange of theories and ideas which often leads to consensus and thereby conclusions.

The BBC programme Inside Science on Radio 4 is deservedly well-respected, explaining and commenting on sometimes complex issues in a way that the science can be easily understood by the average person. It’s sad, therefore, that this track record was somewhat tarnished last month. An episode on bovine TB and DEFRA’s recent statement to phase out the badger cull when and where practicable involved an interview – indeed the only interview – with Professor Rosie Woodroffe, a well-known opponent of the cull.

What surprised a number of scientists who are experts in the pathology and epidemiology of bTB, the battle against it in cattle and the efficacy of the badger cull, was the fact that not one of them was also interviewed, allowing Professor Woodroffe to make some outlandish comments without being challenged. In championing the use of vaccine in both badgers and cattle, she added that the main route of transmission is from cattle-to-cattle and that there is no real problem for those badgers that contract the disease.

Professor Woodroffe also said that the current culls have produced no positive results in reducing the number of reactor cattle and that the culls have caused disruption in badger groups forcing infected animals into territories left vacant by those removed, known as perturbation.

The BBC has now received letters of complaint regarding the programme.

Dr Lewis Thomas, secretary of the Veterinary Association for Wildlife Management said, “What Professor Rosie Woodroffe fails to recognise in her plausible but flawed response is that there is no effective vaccine against bovine TB for either cattle or badgers. The only vaccine available, the Bacillus Calmette-Guérin (BCG) vaccine is not a reliable or efficacious vaccine in man and other mammals (only 70% efficacy in man). It has been in existence for nearly a century and attempts to improve it over the years have not met with success. The so-called recent breakthrough in cattle vaccination, production of the DIVA test that differentiates vaccinated cattle from infected cattle, is no advance in immunisation/protection of cattle over previous unsatisfactory trials with BCG.”

Continuing, Dr Thomas states, “Ms Woodroffe makes the remarkable claim that badgers do not suffer from the disease. She is clearly unaware of the pathology of the disease in badgers. Tuberculosis is a severe disease in any species and the badger is no exception. It has been documented in detail some 20 years ago as a cause of lingering death with extreme emaciation and progressive respiratory distress, resulting in it being the single largest cause of death in adult badgers.”

Roger Blowey, Fellow of the Royal College of Veterinary Surgeons, was equally annoyed by the programme, “I was amazed at the hugely biased interview with Professor Woodroffe in last week’s programme. The actual current state of knowledge regarding bTB in cattle was totally ignored”. Addressing further points regarding vaccination, he said, “A perturbation effect has only ever been shown to exist during the Krebs/RBCT cull, and even then for several years post culling, bTB levels in cattle were considerably reduced in the 2km perturbation zone…Cattle vaccination has been tried in the past, and found to be unsuccessful. In a massive UK trial, over 6000 calves were vaccinated every 6 months for ten years. At the end of the trial it was found that the vaccine had not eradicated TB from any of the herds. It was for this reason that the Government of the day decided to adopt the ‘test and cull approach, a strategy that was enormously effective, almost eliminating TB from the UK by the mid-1980s. Unfortunately, from the 1990s the massive -probably 20 fold – rise in the badger population, combined with the explosive increase in bTB in badgers, has led us to the current situation…The only UK badger vaccination trial (in South Gloucestershire) found that, after 4. 5 years of TB vaccination of badgers, there was absolutely no measurable effect on bTB in cattle. In comparison, after 4 years of badger culling, there was a 66% reduction in bTB in the Gloucester cull zone.”

Emaciated female badger, half normal weight and with advanced lesions of bTB throughout her body. The disease “doesn’t really do the badgers any harm” according to Professor Woodroffe.

The DEFRA announcement, if read carefully, states that culling can reduce when circumstances allow, but what perhaps should have been predicted was a hijacking of the press release by groups vehemently opposed to the cull, along with their false claims that culling was always wrong and had never worked, while at the same time promoting the effectiveness of vaccination.

At the time of writing, no response has been received from the BBC or from Professor Woodroffe.

A relevant question is raised by Dr Thomas. “Why does the government consistently appoint people to head up enquiries whose area of expertise is not in the relevant field?” he asks. “In the case of bovine TB, scientists have been employed who are not experts in the epidemiology of the disease. This has occurred in other fields, such as the examination of the physiology of deer during hunting, and often leads to incorrect conclusions.”

Such fake news has become a fact of life in controversial matters, especially where animals are concerned, but what is far more depressing is a well-respected science-based programme, on this occasion, dropping its standards to join in.

 

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