Monday, August 11, 2008

"Zoonosis" - define.

While many attempt to pigeonhole the disease caused by m .bovis - b.Tuberculosis, to either cattle or badgers, depending on your point of view, its significance, control and eradication should be defined by its 'zoonotic' status.

B.tuberculosis passes from animals to other animals, and to human beings. Thus it is known as a 'zoonosis'. That is what they do. So it was 'disappointing' to read in Western Morning News a story where the disease was said to 'crossed species' and infected a veterinary nurse. In a lightweight jumble of disparate quotes, farmers organisations distanced themselves from milk / meat and stressed how many cattle were being slaughtered, while Andrew Biggs speaking for veterinary organisations, suggested the infection could be linked to badgers - but that cattle may be involved too.
Fears have been raised about the spread of bovine TB after the disease crossed species and infected a Cornish woman.
The patient, who has not been identified but is believed to be a veterinary nurse, is undergoing treatment for the serious respiratory infection.

The WMN opinion column (no link) has a more coherent view. They realise that drawing attention to a 'human' case of bTB, risks suspicion falling on cattle products, but quantify their publicity thus:
".. Government does have a responsibility to tackle the problem. And that extends to dealing with the reservoir of bovine TB in wild animals, which inevitably means a cull of sick and dying badgers.
There was speculation yesterday that a badger was the more likely source of this case. Swift testing [and slaughter - ed] of cattle, means cases among domestic stock are caught early on, while the disease runs rampant among wild animals, from which domestic pets can catch the illness and pass it on. If that is the case here, it ought to make even Mr. Benn sit up and take notice.
If diseased badgers are implicated, not only in passing this illness to cattle but to at least one person as well, the excuse for failing to act with a badger cull will surely become untenable. There is no need for panic, but there is now a desparate and overwhelming need for action. "

More on this story comes from Farmers Guardian who have some delicious quotes from a Defra spokesperson:
“We are aware of a case of M. bovis infection in a human patient in South West England, and the patient's dog. The patient is receiving treatment,”
“M. bovis is a recognised zoonotic agent and that is precisely why we have a compulsory bovine TB control programme in cattle."
"Bovine TB can affect domestic pets such as dogs but the apparent incidence is low.”
On that final quote, we remind Defra to 'watch this space'. It is only two years since Hilary Benn's predecessor, another Ben - Bradshaw made bTB notifiable in 'all mammalian species'. That means that veterinary practitioners have a duty of care to forward suspect cases for full post mortems, at the taxpayers' expense. And once a problem is sought out, then it is more likely to be found as our posting below illustrates.

Playing devil's advocate here, we trust that the whole machinery of tracing has clanked into force? This unfortunate lady, (and of course her dog) will have had numerous 'dangerous contacts', which must be traced and tested. All the animals she has handled, petted, treated (?) in the veterinary practise where she worked for starters. Then her dog's contacts. Other dogs? his favourite lamp-post? fields and footpaths?

This whole scenario throws into sharp focus the utter futility of slaughtering thousands of cattle, whose test results show they have had 'exposure' to the zoonosis known as bTB, while leaving the cause of that exposure - said to be 80 - 90 percent in areas of high incidence - to mushroom out from the original 7 or 8 badger hotspots ten years ago. As seen from Defra's TB incidence maps, just like Topsy, these areas have 'amplified' (Defraspeke) into red blotches which now stretch from Lands End to Cumbria, giving users other than tested cattle, opportunity for contact and spillover transmission.

So our comment on this story is - it was inevitable. And this is not the first time it has happened And as long Defra are content to slaughter sentinel tested cattle, while leaving the source of their problems to spread rampant infection across England's green and pleasant land, the potential for transmission into human / domestic pets and all other mammals is also 'amplified'.

The inappropriately named 'bovine' Tuberculosis is a zoonosis - it's what they do.

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