TB IN CATTLE?
1. We recognise that the risk of TB transmission
from meat to humans is negligible, but public health concerns
are paramount in our policy decisions. Professor Sir John Krebs
concluded that the current risk of human infection with M.
bovis in Great Britain is negligible. However, the disease
has the potential to cause problems and a rationale underlying
policies for control of bovine TB is to ensure that this risk
does not increase. He therefore recommends that the incidence
of M. bovis TB in humans should be kept under review in
the light of the increasing incidence in cattle. To this end we
have established a joint MAFF/Department of Health group which
meets quarterly to monitor the situation.
2. The disease still remains a serious threat
to cattle. The incidence of TB in cattle has been rising since
1990, and in 1998 over 6,000 cattle were compulsorily slaughtered.
This represents a huge financial burden to the industry and the
taxpayer, and has welfare implications for the cattle and other
animals which contract the disease. Bovine tuberculosis also causes
considerable distress to farmers and their families.
3. Following a review of scientific knowledge
in this field, published in the Krebs Report, the Government
announced a package of measures designed to provide a science
based approach to controlling TB in cattle. This package includes
vaccine research and development, epidemiological work to improve
our understanding of the disease and how it is transmitted to
and between cattle, and research in improving testing and diagnosis
to detect the disease more quickly.
4. The report also concluded that the evidence
that badgers were a significant source of infection in cattle
was compelling, but that because the relevant data had not been
collected and analysed, it was not possible to state how large
a contribution badgers make to cattle infection nor how effective
badger culling had been in controlling TB. Professor Krebs therefore
recommended the culling trial as a controlled scientific study
designed to test the conditions in which the removal of badgers
is an effective method of controlling TB in cattle.
5. As you have pointed out, wildlife species
other than badgers can become infected by M. bovis. However,
previous investigations suggest that badgers are peculiarly susceptible
to TB and the prevalence of infection is higher in badgers than
in any other species. The Krebs report concluded that the potential
for other species to transmit M. bovis to cattle is extremely
small, but that this possibility should be kept under scrutiny.
Two research projects are being funded to help our understanding
of the contribution other wildlife makes to TB in cattle.
6. The TB testing arrangements applied in
this country are based on the principles set out in EC legislation.
The testing frequencies range from annual, in areas where the
average incidence of confirmed TB in cattle over the past two
years has been more than 1 per cent, down to four yearly in most
of Great Britain, where average incidence over the past eight
years has been less than 0.1 per cent. The fact that there has
been no increase in the incidence of TB in much of northern, eastern
or south-eastern England, north Wales or Scotland demonstrates
that these arrangements do not result in uncontrolled cattle to
7. We are looking at how existing controls
could be improved through the newly established TB Forum. Chaired
by MAFF officials and made up of representatives from farming
organisations, veterinary associations and conservation bodies,
its remit is to consider new measures which may be taken to control
TB in cattle.
8. A new epidemiological questionnaire is
being used to gather information on a full range of factors which
might affect the spread of TB. This includes wildlife vectors,
but also husbandry practices, nutrition and local terrain and
climate. A detailed questionnaire will be completed by MAFF veterinary
staff in interviews with farmers, on whose holdings a TB incident
has been confirmed since 1 January 1999. The data collected should
give us a better knowledge about the factors influencing the way
the disease spreads and helps us target future research.
9. We recognise that development of a vaccine
may offer the best long term solution to the problem of TB in
cattle. It is one of the Government's priorities in the fight
against TB. However, this type of research is complex and unpredictable
and scientists estimate that development may take between 10 and
15 years or longer, with no guarantee of success. MAFF is investing
over £1.4 million a year into the programme and it is not
being held up by lack of funding. The research is being undertaken
in collaboration with international experts, drawing on the latest
scientific advances and work already undertaken to find a human
vaccine. In the meantime, TB in cattle needs to be controlled
by other means.