Saturday, June 30, 2007

Dear Minister.....

A group of veterinary scientists and former MAFF /Defra senior officers who were successful in so very nearly eradicating bTb from the cattle herds of Great Britain over the last decades, have written an open letter to the new Secretary of State for Environment, Food and Rural Affairs, voicing their concern over the RBCT trial, and ISG's subsequent report.

We are grateful for the opportunity to publish it in full:

TB policy and the ISG findings

We are a group of former veterinary officers from the State Veterinary Service who have specialised in the investigation and control of bovine tuberculosis over many years. We have previously expressed our serious concerns to the Minister for Animal Health and Welfare about the poor conduct of the Randomised Badger Culling Trials but following the publication of the ISG’s final report we are writing to caution you against serious misinformation given in this report that may lead to an erroneous policy judgement.

As a consequence of the many problems encountered the interim DEFRA report concluded that the efficiency of the culling operation in the proactive culling areas was from 20% to 60% . These figures imply a social disruption and dispersal of 80% to 40% of infected communities ensuring an outward spread of infection. Following the many adverse comments over this poor culling rate the ISG have since adjusted their efficiency as being from 32% to 77%.

Perusal of the ISG’s final report shows that five of the ten initial culls were carried out in mid Winter (4 in Dec/Jan, 1 in Nov to Jan) which is well known to be the least successful time for trapping. Also the mean number of trapping days was only eight per annum. Consciously choosing such a course of action ensured this first cull removed minimal numbers of badgers and maximised social disruption and subsequent dispersal. At site B, Putford, Devon the second cull was also in the Winter exacerbating the disruption. Overall 16 of the 51 culls were conducted at this time.

We have long known that poor culling rates can spread infection and the initial cull must always attempt to maximise the removal of as many sett inmates as possible to avert this problem. It must be remembered that the last large cull, using the same cage trapping method, which was at Hartland, Devon, in 1984 resulted in a fall in confirmed herd outbreaks of TB in cattle from 15% of herds to 4% in 1985. Thereafter annual incidence declined and held at around 1%. In excess of 80% to almost 90% of badgers were removed which required protracted trapping efforts in some of the area. No so called edge effect was found.

The decision by the ISG not to completely remove badgers from the proactive cull areas as recommended in the Krebs report so as to “quantify the contribution made by badgers to the cattle problem” was clearly an error of judgement. The decision rather to reduce the number of badgers and “maintain this population suppression” was scientifically unsound leaving too many variables. This approach would have been expected to induce widespread social disruption.

The ISG have not used good scientific method in their culling approach and the results obtained reflect this. All the assumptions with regard to culling in the RBCT are thus based on flawed data.

We have found no evidence in the ISG report of the “huge reservoir of undiagnosed infectious cases of TB in the cattle population” to which Prof Bourne alluded to repeatedly at the final ISG Open Meeting in London. We consider this assertion to be unfounded.

We wish to caution you about the over statements by the ISG regarding cattle to cattle transmission and poor performance of the tuberculin test. Historically in Ireland and in West Cornwall during the early 1970s draconian testing and slaughter approaches alone made no effect on the incidence of new herd outbreaks. Also this test has facilitated official eradication of TB from all the EEC Member States except UK and Ireland. While the situation in Ireland has greatly improved, with a combined policy of testing and slaughter of reactor cattle and removal of infected badgers, the UK is alone in having a deteriorating problem.

If you follow the ISG recommendations regarding this approach without addressing the primary badger reservoir of infection increasing numbers of cattle will continue to be slaughtered as the TB epidemic continues to escalate. Also more badgers will become infected and the situation in other animals sharing the same habitat will worsen. Currently these include deer, alpacas, lamas, sheep, pigs and domestic cats and ferrets. The possibility of spread to man from some of these animals is real.

Regrettably no significant progress will be made unless effective culling of infected communities of badgers is initiated and rigorously applied.

Yours faithfully

Dr J Gallagher, former Senior Veterinary Investigation Officer, Devon and Cornwall, former Independent Consultant to DEFRA TB Research Division.

R.M.Q.Sainsbury, former Specialist TB Veterinary Officer, Truro.

W.G.A.Ashton OBE, former Divisional Veterinary Officer, Truro.

J.Cohen, former Specialist TB Veterinary Officer, Taunton.

J. I. Davies, former Regional Veterinary Officer, South West.

R.H. Muirhead MBE, former Specialist TB Veterinary Officer, Gloucester.

A.J.Proud,. former Specialist TB Veterinary Officer, Gloucester.

Dr J. A. Smith, former Specialist TB Veterinary Officer, Gloucester.

A. T. Turnbull, former Head Notifiable Diseases Section, Tolworth, former Veterinary Advisor to Krebs TB Review Group.

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