American Bison - Buffalo Field Campaign

may not have been validated. Testing faeces for parasites or
pathogens, such as Mycobacterium avium pseudotuberculosis
(Mptb), may also be beneficial. Active sampling allows
estimation of the population-level prevalence of the disease (as
it can have greater statistical value because it is likely to be more
random than passive sampling), although passive surveillance
as a disease detection strategy may be more suitable for
protected populations. High priorities for disease surveillance,
based on human, wildlife, and livestock health considerations
could include anthrax, bovine tuberculosis, brucellosis, BVD, JD,
and MCF, among others. Finally, while foreign animal diseases,
such as foot-and-mouth (FMD) disease or heartwater, are not
highly likely to affect American bison populations, they should
be on the “watch” list of potential diseases, since introduction of
diseases such as FMD to North America would have significant
economic impacts.
Non-specific signs of disease should be monitored and
investigated, even though diagnostics are required to determine
cause (e.g., poor condition could be due to age or habitat
condition, parasitism, or JD, among other causes; Table 9.6).
9.5.3 Management
When a pathogen has been detected in a bison population,
an evaluation should be made to determine if a disease
management plan should be developed that is consistent
with the goals for the bison population. Potential disease
management objectives are: a) a passive approach where no
actions, or at least no actions that manipulate animals, are
taken to control the disease, b) a control strategy where actions
are taken to limit disease prevalence, spread, or risk, or c) an
eradication strategy where actions are taken to remove the
disease from the population. All three strategies (Table 9.5) will
likely involve monitoring disease prevalence (either actively
or passively as defined above). Strategies used will also be
influenced by the intensity of management within the herd. For
example, management options, such as vaccination, would be
more easily applied to a herd that is intensively managed with
round-ups.
9.5.4 Research
Further research will be necessary to develop and implement
tools for successful disease prevention, surveillance, and
management. For example, many of the diagnostic tests
commonly used in bison disease programmes were developed
for use in the livestock industry and have not yet been validated
in bison populations. Furthermore, key questions remain
about the presence/absence and distribution of diseases in
populations, and their potential effects on bison demography
and genetics.
Table 9.6 Non-specific clinical signs of disease.
Loss of body condition Abnormal behaviour
Abnormal exudates from body
orifices
Research should be designed to meet the needs of local
managers, so that results can be applied in more general
contexts. A limited list of some of the key disease research
themes include:
Diagnostics (specific to bison, with high sensitivity and
specificity to detect a disease);
Vaccination/immunology;
Role of genetics in disease resistance;
Disease epidemiology (e.g., transmission, demography)
and risk analysis (spread of disease among and
between wild and domestic hosts);
Identification of emerging disease threats to bison in
North America;
Pathology;
Effect of disease on population growth and viability
(both indirect and direct effects).
Where research is needed for a particular disease surveillance or
management question, bison managers are encouraged to work
with federal, state, university, and private researchers to meet
this need. An adaptive management approach will be necessary,
especially when information about a specific disease is scarce.
9.5.5 Stakeholder involvement
Isolation from the herd
Cloudy eyes Abnormal loss of hair coat
Diarrhoea Abortion
Abnormally poor hair coat Lameness (multiple limb)
Somnolence Abnormal interaction with
humans
Unexpected/ abnormal
mortality events
In summary, bison populations should be managed to prevent
the introduction and spread of diseases that directly, or
indirectly, impact bison recovery. However, bison disease
management strategies have been, and continue to be,
controversial because the apparent solution to the disease
problems (or “cure”) is often perceived to be worse than the
disease itself. Extensive stakeholder involvement in disease
management plans is absolutely critical to successful bison
disease management; such management strategies have
often failed without it. Typical stakeholders in bison disease
American Bison: Status Survey and Conservation Guidelines 2010 97