Wednesday, October 09, 2013

The Numbers Game

As the Somerset badger cull draws to a close - maybe - the thorny question of how many beans make five has raised its head again. Or in this case, how many badgers there are, pottering around in any one patch at any particular time anyone chooses to try and count them.

 In the early 1970s, while advising on the first Badger Act, the late Earnest Neal described 1 per  as 'abundant' . But after forty years of ultimate, mega protection, FERA cage trapped 844 in 55 sq km during their vaccination 'Elf n' Safety' trial in 2007/8. That is over 15 per sq km. (or 15.5 if one counts half a badger). And in parts of Oxfordshire, population densities of 38 per sq km have been recorded.

Based on the charade known as the RBCT Badger Dispersal Trial, which in its turn, admitted a political steer (link) from its inception, proposals for these pilot culls staggered along with cull protocol organiser, Natural England (link) putting as many obstacles in the way of their success as possible. And being so much attached to mathematical models, numbers were crucial.

And it was these numbers which have proved to be a movable feast. They were however, the key to perceived 'success' : so much so that after the first foray into how many badgers occupied 350 sq km of land, they were changed, stirred and possibly now changed again. (link)

The Independent reports this morning that cull targets have been halved after a hard winter. An announcement is imminent and that the cull has been a success.

Now bearing in mind that this exercise was to see if picking off a nocturnal, subterranean, group mammal in ones and twos over a set period of time (42 nights) in a given area ( 350 sq km) and achieving a 70 per cent cull rate over 75 per cent of the area was 'humane', its 'success' should not be measured by X per cent of Y multiplied by anything at all. Provided no badgers were wounded, free shooting could be deemed a success.

 However we know from the aforementioned Badger Dispersal Trial that occasional 8 nights forays into a population endemically infected with zoonotic tuberculosis using cage traps, was not the best way of dealing with the Grade 3 zoonotic pathogen, roaming our countryside. And done haphazardly, may make things a whole lot worse for resident cattle, sheep, pigs and alpacas.

 There are many rumours flying around about these pilot culls, to which we have no intention of adding anything at all. But while we wait for official comments on this, the latest political shenanigans to avoid culling a known and acknowledged wildlife reservoir of Grade 3 zoonotic pathogen, we muse on the numbers game which has bedeviled these culls. But our observations are not for culling badgers but for vaccinating them.

The accepted protocol for any vaccination programme is that to be anything close to effective, over 80 per cent of the target population must be jabbed or dosed. So one would assume that the badger population numbers would be known at the start? Yes?

No. We are not aware of any pre-vaccination population head-count attempted for this latest wheeze (link) to avoid culling badgers infected with zoonotic tuberculosis. And in fact the protocol for vaccination is just as restrictive, expensive and daft as that dreamed up by NE (Natural England) for its pilot culls.

Readers may be amazed to hear that only 2 nights' trapping is allowed, and if one badger is caught (and that has happened) out of how ever many were expected at this particular party, that's it.

 The operators vaccinating have to pack up and walk away. If none are caught, they may stay a further two nights.

Badgers certainly are not queuing up for their jabs as in Ken Wignall's wonderful cartoon.

The amount of walking involved (for that, read 'work hours') for operators is not inconsiderable too, as live BCG vaccine cannot be mixed from its refrigerated containers ahead of knowing if anything has volunteered for  their traps. So two visits are needed from vehicle and fridge to each trap site - and back. And that can be miles. But at least it's good exercise for the vaccination operators, if not particularly fruitful as no one knows if the trapped animal already has zoonotic tuberculosis, or what part of a larger group number he may constitute..

The consequence of this slap happy, comfort blanket is that  no one knows how many of the endemically infected resident badger population they have jabbed with a vaccine now boasting an assumed 54 per cent efficacy, and of those jabbed, how many were already infected (FERA's haul of 844 had a 43 per cent infection level, which was said to be 'typical of badgers in endemic areas'). They haven't a clue. Because contrary to the the X and Y multiply and divide critically modeled cull protocol, for vaccination, no population count ahead of vaccination or pre screening for existing disease was undertaken at all.

So while a cull, (in some form) which eventually will prevent the spread of zoonotic tuberculosis, is tied in a cats' cradle of red tape on numbers, before, during and after the event, vaccination of that same species appears to be so very much more relaxed.
So much so that the difference and perceived outcome, is quite astounding.

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