in the bTB firing line
is wreaking havoc on the UKs farming industry and the badger has been
targeted as a culprit. But is it really to blame?
Peter King, Executive Committee Chair at the European Livestock Association,
NFU Director, Anthony Gibson, and Animal Health and Welfare Minister Ben
Bradshaw, are among those Neil Davey speaks with to find out.
by Dr Helen
Evidence suggests that trace element deficiencies induce a susceptibility
to M.bovis, which can be corrected by restoring the nutrients to depleted
soils, particularly in the hot spot areas that occur on soil types intrinsically
deficient. Furthermore, inadequate trace element intakes are a risk factor
for false negativescattle that do not respond to the TB skin test
because their circulating lymphocytes are suppressed, a condition known
as anergy. These are silent carriers, healthy in themselves, but whose undetectable
infectivity could explain the persistence of the hot spots. Suppressive
factors include zinc, selenium and cobalt deficiency. Adequate trace element
intakes would lift the suppression and allow the silent carrier to be identified
by the skin test.
TB: Vaccine research
Developing a TB vaccine
for badgers and cattle is a long-term goal and a substantial part of the
Defra research programme focuses on this. Over the past 7 years we have
invested more than £10.5 million in vaccine development and associated
research. Real progress has been made. Testing candidate vaccines in naturally
infected cattle and badgers, and developing novel vaccine delivery systems,
is underway and we have committed to future funding of approximately £5.5
million per annum on this work.
vaccination one step closer?
Control of bovine tuberculosis
(bTB) using vaccination could be one step closer in the UK, with the development
of a test able to distinguish between vaccinated and infected animals.
TB is on the increase in the UK cattle herd, costing more than £90m
a year and vaccination is under active consideration, say the
Institute of Animal Health. This would involve using the same vaccination
used to immunise humans against the disease, BCG.
human vaccine may protect cattle from TB
A vaccine to protect cattle against highly infectious bovine tuberculosis
is to be tested in national herds within three to five years, following
successful trials in laboratory animals.Government vets plan to use a modified
form of the human BCG vaccine to protect cattle from the disease, which
was responsible for at least 20,000 animals being sent for slaughter last
The disease was almost
eradicated from the national herd in the 1980s but there has been a dramatic
resurgence since, with cases rising 14% year on year. The disease cost the
taxpayer £80m last year in compensation paid to farmers.
Tuberculosis in cattle and badgers
Bovine Tuberculosis (bTB) was a major problem in cattle herds earlier this
century but was virtually eradicated by tuberculin testing and slaughter
of infected cattle. However, bTB has persisted in southwest England, its
traditional stronghold, some parts of Wales and the West Midlands, and is
now increasing in other parts of Britain. Since the mid-1970s tens of thousands
of badgers have been culled in response to bTB outbreaks because of circumstantial
evidence that badgers spread the disease.
for discussion on Bovine TB in the UK. Ruth Watkins.
I have been surprised to learn that veterinary public health microbiology
is not conducted in the same way as in human medicine and there are no trained
clinical specialists nor is there peer reviewed best practice. The only
veterinary laboratory in the UK doing work on TB funded by government grants
is Weybridge, and in order to get funding for their work the scientists,
few of whom are vets, must formulate
hypotheses to competitively bid for research funding or carry out government,
DEFRA, commissioned work to devise a new test such as to detect the gamma
interferon response specific for M bovis infection using peptides derived
from proteins absent in the BCG vaccine (Bacille Calmette Guerin) but expressed
by M bovis.