Wednesday, June 27, 2007

From the outside, looking in

It is enlightening to see an overview of how others see our efforts to eradicate bTb, and their reaction to the flood of papers and research generated. Did we say 'beneficial crisis'? Yes, we did.

An insight from New Zealand microbiologist, J M O'Donnell, working in the field of immunology we post below, particularly in the light of the ISG's conclusion that bearing down on the disease only in cattle, will have a disproportionate effect on overall disease incidence if the wildlife reservoir left.

Commenting on the Gilbert study of cattle movements, Mr. O'Donnell says:

This study could also be interesting to contrast with the known spread of BTB in general regions. As it predicts BTB spread based on cattle movements, it does immediately present a means to experimentally verify it on the ground (so to speak). Given their model, it should be expected that movements from areas with BTB should be associated with the detection of certain Mycobacterium bovis spooligotypes (basically strains). This is because the imported infected cattle should bring with them their M. bovis types and therefore spread that to the uninfected herd. Over time, based on what cattle movements went into a region and what spooligotypes infected cattle bought with them, you would expect to see those spooligotypes in subsequent herd breakdowns.

Here is where I become somewhat skeptical. It’s known from previous experiments which have analysed the spooligotypes of M. bovis from badgers and cattle that these tend to be shared between the two species (see part III). This also tends to be isolated by geographical regions, with a mixture of spooligotypes but only a few ‘oddball’ ones that aren’t shared between badgers and cattle. In the model predicted by Gilbert et al., 2004, where cattle movement is the primary motivator for BTB spread it also implies cattle to cattle spread. The lack of spooligotype mixing between regions from studies conducted in Ireland (for example) have shown spooligotypes of M. bovis tend to be similar in a region but not between them, raises concerns over cattle movement as a predictor of M. bovis. It may be likely that cattle movement helps to spread the infection to a new region, but is not sufficient to determine if the disease will be able to establish in the new region.


Anonymous said...


27 June 2007

With a cull of diseased badgers seemingly as far away as ever, cattle
farmers in the South West are turning increasingly to homeopathic
prevention to stop their livestock catching bovine tuberculosis.

Sales of Ainsworths' TB preventative are booming, according to agent
Geoff Derges, who said the product had grown steadily in popularity over
the past three years.

"It requires the administration of just five millilitres added to the
livestock's drinking troughs every 14 days for eight weeks, then
regularly every 30 days," said Mr Derges, from Barnstaple.

"As test dates vary from farm to farm extra information is required to
suit an individual situation."

The publication of the report of the Independent Scientific Group, which
stated a cull of diseased badgers would not necessarily help stop the
spread of the disease, had served to increase interest in the
homoeopathic product, he said.

"Farmers need to talk to me to discuss administration rates, which
depend entirely on when their herds are being tested," he stressed.

"All we are doing by administering this liquid is building the animals'
natural immunity. It is a preventative, not a cure - being used as an
insurance policy."

But Mr Derges said he could not divulge what was in the liquid.

"We are trying to spread the message to farmers that this is a way
forward," he added. "Up to now interest in this product has been through
farmer-to-farmer recommendation."

A 100ml bottle costs £75.

Matthew said...

Anon: 2.14
Thanks for that. Herd health is important for resistance to any disease.