1 Introduction
1. Bovine tuberculosis is a disease of global importance
and one of the biggest challenges facing the cattle farming industry
in the United Kingdom today. It is a disease with public health
and international trade implications. It is caused by the bacterium
Mycobacterium bovis (M. Bovis) which can infect and cause
TB in many other mammals than cattle, including badgers, deer,
goats, pigs, camelids, dogs and cats. Furthermore, M. Bovis
has zoonotic potential[1]
and in certain circumstances can be fatal in humans.[2]
In the European Union, M. Bovis accounted for 132 cases
of human tuberculosis in 2011, 31 of which were in the UK.[3]
2. Bovine TB is present, and in some areas increasing,
throughout Europe, but, with the exception of Ireland, the scale
of the problem in the United Kingdom is significantly greater
than in any other country in the European Union.[4]
In 2011, of those countries with an EU co-financed eradication
programme (i.e. those with the greatest problem), proportionately
more herds tested positive for bovine TB in the United Kingdom
than any other country.
Table 1: Mycobacterium bovis in cattle herds in
co-financed non-OTF Member States in 2011[5]
| Non-officially free MSs
| No. of existing herds
| No. of positive herds
| % existing herds positive
|
| United Kingdom | 106,131
| 9,620 | 9.06%
|
| Ireland | 116,061
| 5,002 | 4.31%
|
| Spain | 126,473
| 1,485 | 1.17%
|
| Portugal | 58,503
| 267 | 0.46%
|
| Italy | 128,393
| 488 | 0.38%
|
While Ireland, Portugal, Spain and Italy have seen
a decrease in the proportion of herds testing positive for bovine
TB since 2008, the overall proportion of existing herds testing
positive for the disease in the United Kingdom increased from
2.88% in 2008, to 5.58% in 2009, 8.63% in 2010, and 9.06% in 2011.
The highest financial contribution from the EU budget to eradicate
animal disease (€31m out of €203m) goes to the UK for
its bovine TB eradication programme.[6]
3. Bovine tuberculosis is estimated to have cost
the UK taxpayer more than £500 million over the last decade
and is predicted to cost more than £1 billion over the next
10 years unless there is further action.[7]
It causes a huge emotional and financial strain on farmers whose
herds have to be regularly tested and subject to movement controls
and whose infected cattle must be culled.[8]
In 2012 alone more than 8 million tests were carried out on cattle
in Great Britain and 37,754 cattle were slaughtered. According
to Defra, there are approximately 10 million cattle in the UK:
'a little over two million adult dairy cows in the UK, a little
under two million adult beef cows, and about six million younger
animals'.[9] In 2012 it
is estimated that 1% of the dairy herd was slaughtered because
of bovine TB.
4. Bovine TB is primarily a respiratory disease.
There are thought to be two principal methods of transmission.
Transmission can occur directly through close contact between
infected and uninfected animals whereby uninfected animals inhale
droplets containing M. Bovis bacteria exhaled or coughed
by infected animals. It may also occur indirectly through ingestion
of water or feed that has been contaminated with excretions or
discharges from infected animals. The latter method of transmission
is more difficult and more M. Bovis bacteria are required
to infect an animal by ingestion than by respiration. Both direct
and indirect transmission methods potentially occur at pasture
and in farm buildings.
5. While bovine TB is transmitted between cattle,
it is widely accepted that where wildlife populations constitute
a reservoir of M. Bovis, wildlife to cattle can be a route
of infection though the precise nature of the transmission remains
poorly understood. Since the 1970s and the discovery of badgers
infected with M. Bovis, studies have demonstrated the presence
of infected badgers across large parts of the United Kingdom and
Ireland, that badgers excrete M. Bovis, and that they are
a potential source of M. Bovis for cattle.[10]
The role of the badger in the spread of bovine TB amongst cattle
is an emotive issue and their relative contribution a matter of
intense debate. As Professor Hewinson, Chief Scientist, AHVLA,
told us:
One of the real evidence gaps is how much TB
is given from cattle to badgers, how much TB is given from badgers
to badgers, how much TB is given from badgers to cattle, and how
much TB is given from cattle to cattle.[11]
The Government has made its position clear that in
order to control the disease in cattle it must also be tackled
in badgers. In December 2011 the Government announced that it
would pilot two badger culls. The United Kingdom is not the first
country to consider the culling of infected wildlife as a means
of combating bovine TB in cattle; the USA (white-tailed deer),
New Zealand (brushtail possum) and the Republic of Ireland (badger)
have all included this approach in their efforts to control the
spread of the disease. The UK is the only EU country to have given
its wildlife vector, in this case the badger, protected status.[12]
In addition to the pilot culls, the Government announced that
up to £250,000 a year will be made available
over the next three years to support and encourage badger vaccination.
The Government has already spent £35 million on developing
badger and cattle vaccines since 1994 and plan to spend another
£20 million on the development of practical and usable vaccines
over the next five years.[13]
6. The aim of our inquiry was to explore the extent
to which vaccination can contribute to the control and eradication
of bovine TB. When the Government announced plans to pilot a strategy
of culling badgers many interested parties questioned why a programme
of vaccination, both of cattle and badgers, was not being considered
instead. In conducting this inquiry, we set out to question the
key people involved in researching, licensing and legislating
on a vaccination approach to the prevention of bovine TB and to
get on public record their views on the availability, cost and
effectiveness of a vaccine for cattle, an injectable vaccine for
badgers and an oral vaccine for badgers. We are grateful to all
who contributed.
1 Can transfer from animals to humans Back
2
In 2009, 10 EU countries reported 133 cases of M. Bovis in humans
with mortality at 5.3% (source: http://veterinaryrecord.bmj.com/content/172/12/310.extract)
Back
3
Scientific Report of EFSA and ECDC: The European Union Summary
Report on Trends and Sources of Zoonoses, Zoonotic Agents and
Food-borne Outbreaks in 2011,EFSA Journal 2013, 11(4):
3129, 9 April 2013, http://www.efsa.europa.eu/en/efsajournal/doc/3129.pdf Back
4
Q 103 Back
5
Scientific Report of EFSA and ECDC: The European Union Summary
Report on Trends and Sources of Zoonoses, Zoonotic Agents and
Food-borne Outbreaks in 2011,EFSA Journal 2013, 11(4):
3129, 9 April 2013, http://www.efsa.europa.eu/en/efsajournal/doc/3129.pdf Back
6
Q 103 and Commission Implementing Decision 2012/761 http://ec.europa.eu/food/animal/diseases/eradication/programme2013/2012_761_eu_en.pdf Back
7
Defra website, http://www.defra.gov.uk/animal-diseases/a-z/bovine-tb/ Back
8
11.5% of herds in England were under movement restrictions in
2011. The average cost of a TB breakdown on a farm is £34,000,
of which £12,000 falls to the farmer (source: Defra website,
http://www.defra.gov.uk/animal-diseases/a-z/bovine-tb/). Back
9
Defra website, http://archive.defra.gov.uk/foodfarm/farmanimal/diseases/vetsurveillance/species/cattle/ Back
10
Chambers et al, Bacillus Calmette-Guérin vaccination reduces
the severity and progression of tuberculosis in badgers, Proceedings
of the Royal Society: Biological Sciences, 22 June 2011, vol.
278 no. 1713 1913-1920 http://rspb.royalsocietypublishing.org/content/278/1713/1913.full Back
11
Q 308 Back
12
The badger is protected under the Protection of Badgers Act
1992 which protects badgers and their setts. It consolidated and
repealed the Badgers Act 1973, the Badgers Act 1991 and Badgers
(Further Protection) Act 1991 Back
13
Defra website, https://www.gov.uk/government/news/update-on-measures-to-tackle-bovine-tb Back
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