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Bovine TB. Email received July 23 2009

Mary ,
The TB vaccine and badgers letter is just so true.

 We do not have sensitive and specific testing methods for differentiating truly diseased cattle, with widespread infection ( rather than just picking up cattle that have met and raised an immune response.).  So many head of cattle are culled when not openly infected. The problem in TB is that we do not have an effective vaccine either.   So we are faced with this huge dilemma:  Any animal that has met the disease and contained it, may under conditions of stress, other illness or just older age ( also seen in humans) experience recrudescent disease which is then infectious and so transmissible to other species including man.  Cattle and badgers both fall into this category.

If badgers are the present major reservoir, and if they are the source of this disastrous increase in the infection in our herds, widespread and continued baiting with more than one antibiotic may reduce the infectious load.   This would be potentially useful for the few often excluded animals that are heavily infected and transmitting the organism. But we risk in this way also creating a resistant strain of Mycobacterium bovis.  and other gut bacteria'     Oh how wonderful it would be if we had an effective oral vaccine that could also be placed in bait.  Alas, in 2009 we do not have this facility.

An alternative could be oral contraceptive bait for badgers and thus a slow decline in numbers. But we do not know how this would affect the hierarchy of colonies (nor for that matter their pension arrangements).

In truth the organism is still one step ahead and we simply do not know what is best for all the species involved.

It is a very distressing time for everyone trying to address this problem.

As ever , Colin


Dr Colin G Fink