Bovine tuberculosis

Managing Bovine Tuberculosis: Successes and Issues 243

pasteurizers; ensure they are

being used correctly and that all

milk coming from the pasteurizer

is bacteriologically safe and pro-

tein quality is unaffected.

ii. Livestock TB surveillance

1. Undertake surveys to iden-
   tify at a herd and animal level
   the TB prevalence for each live-
   stock species used for milk or
   meat.


2. Isolate the species of myco-
   bacteria from a cross-section of
   samples cultured.


3. Ideally, the samples selected
   should be based on a test-and-
   slaughter programme where a
   geographically representative
   cross-section of stock ownership
   and types of livestock are tested.
   All test-positive animals should be
   slaughtered. Samples from all TB-
   like lesions found in carcasses at
   slaughter to be submitted for
   mycobacterial culture and myco-
   bacteria isolates typed to species
   level. If a test-and-slaughter pro-
   gramme is not feasible, then the
   survey could be based on animals
   sent to an abattoir. However,
   unless the quality of inspection
   was high, this may provide a
   biased result.


4. Surveillance would provide,
   for each selected country, an indi-
   cation of the countrywide TB
   prevalence for each livestock spe-
   cies sampled and it would deter-
   mine the relative proportions of
   M. bovis and M. tuberculosis cases.
   It may also identify whether a
   particular livestock species or

region of the country poses a

greater threat of infection to

humans. The surveillance results

should assist in identifying a

course of action that has the

greatest probability of reducing

transmission of M. bovis to

humans and in-contact animals.

This would include better target-

ing of communication and possi-

bly introduction of other TB

control methods.

iii. Vaccination of livestock

1. Given a particular livestock
   species or spatial distribution of
   infection in livestock is identified,
   targeted vaccination of young
   livestock could provide a way of
   reducing future infection in that
   species or area.
   i v. Test-and-slaughter of reactors


2. If TB infection is identified to
   be particularly high at a herd or
   flock level as well as within herds
   or flocks, and there is a need to
   rapidly reduce the risk of livestock
   related human infection that can-
   not be achieved by pasteurization,
   then test-and-slaughter of the
   high-risk livestock species should
   be undertaken. This requires a TB
   programme to be developed and
   agreed to by representatives of
   livestock owners, government
   officials and knowledgeable
   veterinarians.


3. Implementation of such a
   programme is likely to require an
   ability to replace slaughtered test-
   positive livestock with equivalent
   TB-free animals at no cost to the
   owners.

References

Abernethy, D.A., Denny, G.O., Menzies, F.D., McGuckian, P., Honhold, N. and Roberts, A.R. (2006) The
Northern Ireland programme for the control and eradication of Mycobacterium bovis. Journal of Vet-
erinary Microbiology 112, 231–237.
Ameni, G., Vordermeier, M., Aseffa, A., Young, D.B. and Hewinson, R.G. (2010) Field evaluation of the
efficacy of Mycobacterium bovis Bacillus Calmette–Guérin against bovine tuberculosis in neonatal
calves in Ethiopia. Clinical and Vaccine Immunology 17(10), 1533–1538.