Sunday, February 07, 2016

Strategy? what strategy?

In today's Sunday Telegraph - [link] columnist Christopher Booker examines the rationale behind Defra's road block on its own research into a DNA test which will identify infectious badgers.

And a road block of some proportions it certainly is, with spurious misinformation freely offered, despite this test, as we remarked in this posting - [link] passing 4 out of 5 strict criteria (when offered genuine positively infected samples, not 'putative') And it achieved this even when the 'blind' testers used half the optimum samples required, one tenth of the bacteria and a third of background prevalence it needed for the best results.

What was left was 'specificity' (false positives) at group level which was described as 'borderline'..

But the samples were singles, were they not? And the group level specificity was 'calculated' from 1 animal out of 10. We think what Defra's apparatchiks did, was to take a single sample / badger? at say 99 per cent specificity and model it back to a group, thereby creating a heap of falsely accused, but very dead badgers.

But qPCR cannot to be modeled. It is DNA. So a simple answer - Yes or No, but not the milkman.
It is also a group test, not a single animal test.

These are the results chart for  Warwick University's Test B in Defra's 'blinded' trial.

The reason for this rejection and all the hubris surrounding it, is we think, that once zTB is found in an animal - any animal - then under International Statute, responsibility for its eradication commensurate with dealing with a grade 3 zoonotic pathogen, passes to Defra. It cannot be shafted onto farmer funded population reductions. Thus a battle is raging, as Booker explains:
" The truth is, I learn on very good authority, that a battle is raging, with officials still too much under the influence of the animal rights lobby, who are stopping further research needed to perfect the test. If they win, it would be a scandal not only to those thousands of cattle farmers for whom TB has been an appalling tragedy.
This is a tragedy for all the healthy badgers too. Badgerists please take note.

Thinking about this 25 year strategy which Defra are ratting on about, (21 now as the first four years have elapsed - but let that pass) designed apparently to eradicate zTuberculosis from our shores, we have come to the conclusion that it is not a 'strategy' at all.

What this country has is a reactive, annual, farmer funded cull, over very few of the affected areas, repeated in 4 year bites, 25 times plus a shed load of cattle measures. And then what? When areas deemed to have jumped through enough of Natural England's hoops have completed their 4 years, there is nothing at all to put in place afterwards. No 'management' at all.

And the so called, but ever moving 'Edge' area with its expanding number of TB restricted herds and slaughtered sentinel cattle? That mobile buffer between the High Risk area, steeped in cattle measures and infected badgers, and the far North, North East and Eastern counties, for whom zTB is a distant problem. For those farming cattle in the Edge, with an ever increasing, bubbling  infection, there is nothing at all.

 So when we speak of using qPCR to locate infectious badgers, we do not mean as an alternative to an initial population reductions in the areas where badgers are so abundant - [link]  and their infection rates extend to half the population.

We see this technique of DNA matching as a long term tool, to screen and manage infected groups of badgers (and wild boar or deer) over the whole country as and when they occur. Disease driven. And certainly to give the pilot cull areas some sort of safety net after their 4 year stints.

 The alternative is to leave infection to build up to the extent which is seen now in Wales, the West and South West, and then apply for a four year wipe out cull. Which is no strategy at all.

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