http://blog.38degrees.org.uk/2011/07/19/badgers-trial-shoots-to-go-ahead/
Today, the government announced it plans to go ahead with two trials of shooting badgers. This would be part of measures to reduce the spread of disease – bovine TB – between different herds of cattle. Badgers can carry the disease and as a result many farmers are keen to reduce their numbers as they think it’s essential for controlling the disease. Caroline Spelman, the Environment Secretary, says she is “strongly minded” to back the shooting of badgers.
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To understand what is going on here, you have to know a little of the history of bovine TB (bTB) in Britain. Firstly, the bTB agent isn't host-specific; it can cause disease in cattle, sheep, badgers, humans, deer and even camelids (it seems to hit alpacas especially hard). Back in the 1940s, bTB was endemic in Britain and readily jumped species from cows to badgers and back.
Cattle testing based on immune reaction to bTB antigen was introduced and this allowed infected cows to be found and culled. This effectively stamped chronic bTB out of the cattle herd, but badgers remained infected. Culling infected setts by gassing with hydrogen cyanide was introduced, and by the 1980s had almost wiped out bTB in Britain; had the campaign been carried on this would have been achieved by the early 1990s.
However, the badger culling was suspended, and this led us to the present situation. With strong protection badger populations increased greatly, but with them spread the bTB infection from hotspots in Devon and Gloucestershire out to the present widespread area all over southern Britain. Cattle breakdowns (positive tests for bTB) were rare in the 1980s; presently they are common and getting commoner, and the amount of compensation for culled cows is rising steadily; last year's total was around £80 million.
So we are led to the current situation. Badgers are getting to be endemically infected with bTB, and badgers don't respond well to bTB infection; they have a very poor immune response to it, and suffer rapid and widespread disease. Vaccine trials on them also demonstrate that even injections of huge doses of vaccine don't have all that much protective effect; there is not an oral vaccine for badgers yet (this would need to be partly transgenic to be effective), and given how poor the response to BCG was, there is unlikely to be one.
Vaccinating cows against bTB is also out of the question. The vaccine for bTB is live, weakened bTB bacteria; the immune response thus generated is identical to that from naturally infected animals. As it happens bTB is rather good at evading immune responses; the humoral inflammation response is the only one which really slows it down. Cows are actually quite resistant to bTB; badgers alas are extremely poor at this.
The Government now cannot let this one lie, since to do so is to risk Britain being declared to have endemic TB (which cuts out our dairy export market), and in any case will only lead to a steady rise in compensation for culled cows as the disease spreads through the badger populations. Local badger culling is the only option left, unfortunately.
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