Friday, November 30, 2012

Spoligotyping gets headlines.

Making headlines in the Daily Telegraph today is a study by Glasgow University on the different strains or 'spoligotypes' of m.bovis circulating between tested, slaughtered sentinel cattle, and free ranging badgers in which Tuberculosis is endemic.

We have discussed this many times and quoted a previous Parliamentary question to explain what 'spoligotyping' means:
"Spoligotyping is used to determine molecular type for all isolates of the bovine tuberculosis bacillus (M. bovis) obtained from badgers and cattle. Variable Number Tandem Repeats (or VNTR), a technique able to subdivide some spoligotypes, is also used. Generally the different strain types of M. bovis that these techniques identify exhibit distinct and probably longstanding geographical clustering. Within each geographical cluster the same strains tend to be found in badgers and cattle ".

So there is nothing really 'new' in this research, which can be read on this link.

VLA have been logging the spoligotypes of bTB for decades now, and produced some very clear maps to show the spatial clustering on the twelve main strains.

And we have pointed out that if cattle were spreading TB across the country as much as some would have us believe, then these maps would be a pointillist picture of a mass of colours and not spatially distinct at all.

Farmers Guardian also covered this subject in this 2007 article, with overviews from people uniquely qualified to speak on TB, its microbiology and epidemiology.


What seems to be the core of the new research is that the VNTR (Variable Number Tandem Repeats) copies of m.bovis DNA have been found to be identical in badgers and cattle on the same farms.

 'Not unsurprisingly' they were identical on the farm of one of our contributers, one who had no bought in cattle, but let that pass.

And the same observation is made of dead cats. After a death due to 'bovine' tuberculosis, the strain type is described as being the spoligotype 'unique to the area'.

We understand that in some areas where sentinel cattle have all gone, domestic cats are now filling the gaps of VLA's spoligotype maps. They use alpacas, sheep and pigs too..... and the spoligotypes, right down to VNTR copies, are likely to be just the same: "unique to the area".

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