SMALL-SCALE FIELD STUDY FOR BOVINE TB VACCINES

Originally from: mona parr
                        
SMALL-SCALE FIELD STUDY FOR BOVINE TB VACCINES
 
Defra is to start a small-scale, three year vaccine field study in badgers as part of its ongoing research to control bovine TB.

Research into the use of a vaccine for badgers has been underway since 1999. It has now reached a stage where field trials are necessary for the next phase of the vaccine licensing procedure.

The study will primarily gather safety data, but will also attempt to assess the protective effect of the vaccine. The badger field study and ancillary diagnostic testing is estimated to cost about £1.1 million a year for three years. Further work on oral vaccine formulation development is to be taken forward from November 2005 at a cost of £500k a year for three years.

The vaccine used, BCG, is the same one used in man.

Animal Health Minister Ben Bradshaw said: "We will be injecting badgers with the vaccine during the study. There are cases where this method of administration may be useful as an alternative to culling, for instance in disease hotspots.

"To that end, both the UK and Republic of Ireland are continuing to carry out work on a version of BCG that can be taken orally."

The proposed field study, which will take place in a high bovine TB prevalence area in the SW of England, should start in mid 2006, at the end of next Winter's closed season. Defra is now seeking landowner permission and evaluating improved diagnostic tests to support the study.

Defra has also announced further work looking at new vaccine candidates and delivery protocols in a natural transmission study in cattle at the Veterinary Laboratories Agency. A naturally infected herd will be used to compare the effectiveness of several vaccines.

http://www.defra.gov.uk/news/2005/050609a.htm

Originally from: mark purdey
                        
TB and elevated iron.
Hi Folks,

This TB outbreak is degenerating the backbone of many of the family farms here in somerset. Most of what is left of our own herd have now developed inconclusive reaction lumps at the last skin test, and, if it follows the pattern of progression as before , then these poor cows will be wholly doomed by the next test in six weeks time.

But this heartbreaking drawn out experience has got me thinking about the origins of TB. What has suddenly made my herd susceptible to TB agent when we have been TB free for all of these years whilst being surrounded by the TB affected cows of neighbouring farms – along with their badgers too ?.

One management strategy has changed on our farm which might give a clue towards the root of our own and other folks TB problem. Drastic cost cutting over the last five years has caused us to terminate our organic registration , which, in turn , has caused us to cease using the superfluous amounts of calcified seaweed and lime fertilisers which we always used to use. The soil has become highly acid as a result. Buttercups are flourishing where clover used to predominate in our pastures.

I typed in the keywords lime and TB mycobacteria into the internet search engine, and lo and behold it linked me onto a massive study carried out in an hotspot endemic zone of mycobacteria infestation in Michigan USA – an area that was known to be an acid soil district. The experiment was to monitor the impact of liming on levels of mycobacteria infection in bovines, and the incidence of infection was reduced by ten fold three years after lime was spread on the affected farms.

The study concluded that the relevant causal criteria was the high elevation of iron in these soils which had been enabled by the acidic nature of the soil. The liming had subsequently rendered the iron unavailable , which , in turn, had lowered the levels of iron in the biosystem of the bovines involved in this study.

What is intriguing, is that iron is required as a pathogenic co-factor in the pathogenesis of TB mycobacteria, and without iron, the TB agent could never really take ahold in the biosystem of the cow or badger.

Amazingly , this high acid / high iron prerequisite is not only extremely relevant to my own farm context here in somerset, but it seems highly relevant to the TB areas right across the UK. The former iron mining areas like the Forest of Dean, The Mendip hills, the Brendons /Exmoor and Mid Devon are all the key areas where TB is rife.

Recent drastic cost cutting in farmer's overall expenditures over recent years has meant that the use of lime has been one of the first husbandry tools to be eliminated ( our local lime salesman confirmed this to me yesterday ). Combining that with the continuation of use of acidifying artificial fertilisers
, the high rainfall of recent winters, etc, the net effect has been one of increased acidification of farmland across the UK. In the areas where high iron is simultaneously present , there is a dramatic increase in opportunity for the TB mycobacteria to take ahold in the iron-elevated biosystems of the bovines and badgers that are resident in these areas.

For once, Margaret Beckett and her side kicks could be right. Why cull the badgers if we are not going to deal with the root of the problem ? Whilst badgers undeniably harbour the TB agent, it might be the high levels of iron due to changes in our management practices / increased rain that has enabled this dramatic TB epidemic to take ahold over recent years.

I have ordered in the lime spreaders onto our farm toute de suite. It may be more economic for governments in the long term to supply lime / or iron chelators for all farmers in TB hit areas as a best means of thwarting the origins of the disease, than to carry on mindlessly slaughtering out the end result ( the TB affected animals ) of what is truly yet another underlying environmental imbalance – at great cost to animal life and the tax payer.

 The TB agent is always going to be endemic in the environment. It only seems to take ahold in the impoverished environments where mammalian immunity is rendered susceptible in some way – witness the sufferers of AIDS who invariably develop TB as a secondary complication ( Aids victims carry high iron levels in their biosystems ) or those living in the industrial slums who were breathing in acidic sulphurous metal contaminated smogs 24 hours a day, etc.

Best,

mark Purdey