Sunday, March 21, 2010

Baaaaa - more sheep

Hard on the heels of our posting below, comes the story this week of a flock of Lleyn sheep, with several 'bovine' TB casualties.
Vets were alerted by chronic weight loss in 20 of 220 ewes and one ram. Postmortem findings in three of the six sheep were consistent with TB and M. bovis spoligotype 10, the predominant strain in local cattle herds and wildlife, was subsequently isolated. Lesions in these three sheep were ‘extensive’, a letter in the Veterinary Record reports.
Farmers Guardian has the story which concerns a farm in Gloucestershire.

Defra's 'other species' TB statistics show 9 sheep samples under culture surveillance for 2009, and for 2005 a couple of positive samples. We told the tale of one of those positives here with Defra contacting farmers who had consigned sheep to Worcester market during late 2005, but who also farmed cattle. As the sheep sample proved positive, farmers who fell into that category were asked to test their cattle.

The tables published by Defra are by no means complete, up to date or accurate.
Although they show 144 positive samples at the time of publishing, that is the number of samples presented to VLA for culture. For camelids, if a herd is heavily infected, we understand that cash is not wasted sampling after the first couple are submitted. Thus the figures for alpaca deaths, personally communicated to vets leading the Alpacac TB Awareness roadshows, are in excess of 140, with some herds losing all their animals. Although veterinary postmortems confirm lesions which indicate TB, Defra has yet to acknowledge these deaths in their stats page - or anywhere else that we are aware of.

432 samples of species other than cattle were sent for culture surveillance during 2009, but many of the later results will not have been posted yet as these tables are compiled quarterly. Of the positives to date, 23 pigs, 26 cats and 68 alpaca make up the bulk of the culture-sample confirmed, 'bovine' TB casualties in 2009.

EDIT addition:
The veterinary press this week has published the story of TB in the Lleyn sheep, but added a cautionary wakeup call to all veterinary practitioners, advising not to confuse CLA with TB lesions in sheep:
Clinical signs and postmortem findings of TB in sheep may resemble lesions of visceral CLA. Failure to demonstrate serological or bacteriological evidence in cases of suspect CLA should trigger a suspicion of possible TB. Colleagues are reminded that suspect cases of TB detected in farm animals are notifiable to Animal Health. The small number of previous incidents of M bovis infection in sheep in Great Britain have been incidental findings at slaughter or at postmortem examination, but have not been associated with clinical signs. The VLA plans to provide more details of this incident in the near future.


Anonymous said...
This comment has been removed by a blog administrator.
Anonymous said...

"This post has been removed by a blog administrator."

So much for free speech.

Anonymous said...

three of the six sheep were consistent with TB and M. bovis spoligotype 10, the predominant strain in local cattle herds and wildlife

option a: the predominant strain in local wildlife

option b: the predominant strain in local cattle herds

Sheep got infection from?:

1/ wildlife

2/ cattle

3/ bacteria in the wider environment

Preferred option: 1


Who got it from?:

1/ cattle

2/ bacteria in the wider environment


No one knows

Matthew said...

Anon 8.54
The comment which upset you was spam mail . Junked.
Do you want really adverts for viagra? We don't.
Even with a filter, some very strange stuff still gets through and clutter up the comments section. Nothing sinister.

Anon 9.08

M.bovis doesn't fly in with the tooth fairy. And it isn't airborne, hence a double back fence to prevent nose to nose contact was/is recommended biosecurity between farms.
Had the Glos. sheep had contact with cattle? Don't know, but regularly tested cattle are pretty non infectious. No cattle are mentioned in the piece.
Would the sheep have been grazing contaminated pasture?
Possibly and probably.

Anonymous said...

Anon 9.08

You didn't mention another possible source of infection - reverse zoonosis.

People do carry deseases, including bTB, and it is possible that for instance a livestock transport driver could carry bTB and pass it on.

Matthew said...

Anon 8.31

We are aware of the possibility of reverse zoonosis. m.bovis spread readily through human beings in the Birmingham nightclub outbreak, affecting another 5 people from the index case (who died..)
In particular we have considered the spreading of sewage sludge from works which take material from a mainly ethnic communities, onto arable farms. (and thus to possible wildlife exposure?)
Should the UV system have a hiccough... then potentially many pathogens could be spread. But it is a long shot for these sheep, particulalrly as the spoligotype is local to the area.

Many questions will need to be posed to the probability of the source of this one.

Interesting that the veterinary press is flagging the similarity of CLA in sheep, to TB and suggesting vets be vigilant.

Anonymous said...

"we have considered the spreading of sewage sludge"

Round here it is not uncommon for farmers to spread slurry (from potentially infected cattle) in fields where livestock - cattle - are grazing.

Don't know if these cattle are 'ethnic community' members

Anonymous said...

"Round here it is not uncommon for farmers to spread slurry (from potentially infected cattle) in fields where livestock - cattle - are grazing."

They'd be organic then.

Anonymous said...

Any volunteers??

Mushrooms help tackle bovine TB, say scientists

Aly Balsom and Caroline Stocks
Monday 29 March 2010 11:35

Feeding mushrooms to cattle could control the spread of bovine tuberculosis, scientists have claimed.

Researchers at RPF Bioscience said compounds found in mushrooms could strengthen the immune systems of cows, helping to stop the spread of bTB between cattle.

Joy Edwards, the firm's head of science, said there was sufficient evidence to warrant testing of a fortified mushroom compound which could be delivered to cattle once a year as a bolus.

"We have been researching the issue of bTB for more than 18 months and have unearthed anecdotal and published evidence to suggest various strains of TB have been treated successfully with mushrooms for many years," she said.

After a decade of research into the effect of mushroom compounds on humans, the company has identified "incredible antibacterial properties" associated with the fungi, she added.

"There is nothing unusual about treating bacteria with mushrooms - think penicillin.

"Mushrooms have been used to treat almost every ailment known to science for more than 3000 years."

Mrs Edwards said farmers were being sought to take part in field trials of the compound across the UK.

The product is in the development stages, but will be marketed as Myco Formula 5 by September this year.

bob said...

It is the testing that is the worrying bit if this site is to be believed.

Matthew said...

The skin test is primarily a 'bovine' tuberculin antigen.
Its efficacy on other species is only now being tested. And on alpacas it is rubbish. Whether that is the case in early exposure and limited disease, we don't know. But once disease is established in camelids, then a negative skin test result isn't worth a light.

It may be that the alpaca has reached an 'anergic' state with edvanced TB and has no more immune response to the test, left to give. Or it may be that it just doesn't work. We don't know.

It works in cattle, and works well.
(We have as a link)