Thursday, June 27, 2013

'Seal' of approval?

This post has been updated.

This weeks' media is full of the story of an injured seal pup washed up in Cornwall, which was subsequently found to have 'bovine' Zoonotic tuberculosis, now identified as a strain found in West Wales.

The report says that this is a unique occurrence, and that no seal has been found with bovine Zoonotic tuberculosis before. Not according to German molecular geneticists Brosch et al, who describe the progression of this bacterium through its DNA as 'developing over thousands of years and now firmly established in:
"... natural host spectra as diverse as humans in Africa, voles on the Orkney Isles(UK), seals in Argentina, goats in Spain, and badgers in the UK." [Brosch et al]
So it is well known that seals can be a wildlife host - but in Argentina. No mention of cattle there either - even for a bacterium with the tag of 'bovine'. Not one. And such geneticists (not celebrity rock stars who just lurve badgers) say that analysis of recent work suggests that true cattle TB was eliminated by the 1970s, and what we have now is badger adapted TB spreading back into the environment.

Which is pretty much what the current Chief Scientist, Professor Ian Boyd, said in his explanation of the genetic development of m. bovis which we reported in this posting.

So how did this seal pup arrive, injured, in Cornwall with a variety of bovine Zoonotic tuberculosis unique to Wales? Cows roaming the beaches of Wales? Nasty farmers infecting all and sundry with their illegally dumped cattle excretions? All and others have been suggested. What part of 'bovine' are you missing, is the usual snipe. And it's called 'bovine' tuberculosis because it 'only infects cattle', is the mantra believed by many dangerously misguided souls.

But many farmers and people who live in coastal areas have reported that badgers are regularly and increasingly seen on beaches, in sand dunes and near the high water line. So it not surprising at all to find a young pup, having sustained what is thought to be a bite wound from a badger, which in turn transmitted generalised tuberculosis.

What is irritating is the assumption that this story is propaganda put out by Defra to support a badger management strategy, but even more irritating shameful is the continued reference to those 'other species' statistics, peddled by Defra, which show the single (one) confirming microbial sample at the beginning of a disease outbreak.

As we've said many times since this came to our attention in 2010, this is deliberate manipulation of the spill over of a deadly zoonosis into other mammals, particularly pets and companion animals. It is inaccurate, recklessly dangerous, and it has to stop.

In late January, we thought a new broom had managed to count most of those 'other species' TB deaths and publish them. Particularly after media reports detailing over 400 alpacas, dead in a single outbreak of bovine zoonotic tuberculosis in June 2012. But no, Defra's table shows 35 alpaca samples for that year, which is what a gullible media hoover up and spit out.

Defra's new, improved tables proved just as inaccurate at adding 2 + 2 and when this was pointed out, they were removed for 'correction'. That was on January 28th 2013.
They too have 'disappeared'.

However, we look forward to seeing the addition of another line in the tables for this Cornish seal, with a Welsh spoligotype of bovine  Zoonotic tuberculosis - in due course. And when, finally those damn tables are accurately reflecting the number of deaths, not just single samples, they may get our 'seal' of approval.

Comments about this story led us to paper published in 1986, in which bovine zoonotic tuberculosis was identified in seals which had died at a marine park in Australia.  Subsequent spoligotyping made a link from them, with onwards transmission to their keeper at the time of their deaths.

 The Abstract of that paper suggests monitoring of keepers, and seal trainers.
In 1986, three seals died in a marine park in Western Australia; culture of postmortem tissue suggested infection with Mycobacterium bovis.

In 1988, a seal trainer who had been employed at the Western Australian marine park until 1985 developed pulmonary tuberculosis caused by M. bovis while working in a zoo 3,000 km away on the east coast of Australia.

Culture characteristics, biochemical behavior, sodium dodecyl sulphate polyacrylamide gel electrophoresis, and restriction endonuclease analysis suggested that the strains of M. bovis infecting the seals and trainer were identical but unique and differed from reference strains and local cattle strains of M. bovis.

The infection in both the seals and the trainer had a destructive but indolent course.

This is the first time that M. bovis has been observed in seals and the first time that tuberculous infection has been documented to be transmitted from seals to humans. Further investigation of the extent of tuberculous infection in seal populations elsewhere in the world seems warranted, and those working with seals and other marine animals should be monitored for infection.

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