ABSTRACT
Many of the emerging diseases worldwide
are shared between domestic livestock, free ranging
wildlife, and humans. Infection by mycobacterial
organisms is not a recent or newly emerging issue, but
the increasing frequency of disease caused by
Mycobacterium species, where wildlife, domestic
livestock, and humans are epidemiologically linked is
cause for concern for wildlife management, agricultural
and public health agencies alike. Human tuberculosis,
including that caused by Mycobacterium bovis,
once thought to be a well understood disease of
lifestyle and socioeconomic consequences is once again a
global concern. Johne’s disease (Mycobacterium avium
subspecies paratuberculosis infection),
previously considered a production limiting disease
important only in domestic ruminants, has recently been
implicated in the pathogenesis of Crohn’s disease in
humans. Furthermore, wildlife and livestock reservoirs
of infection are now considered to be important to the
epidemiology of both of these mycobacterial diseases.
Innovations in diagnostic testing and
laboratory techniques have led to the discovery of many
infectious agents and evidence of non clinical infection
in previously unrecognized species and circumstances.
Among the innovations, molecular DNA detection methods
demonstrate the presence of mycobacterial organisms in
new species not known to show classic signs of clinical
disease and also permit the identification and
characterization of mycobacteria to a much higher degree
than previously possible.
The generation of information is usually
followed by its evaluation and analysis, and a search
for the meaning and consequences of the new knowledge.
At times, new information is merely supportive of
current and conventional thinking, but often it forces
change and the adoption of new principles and ideas. The
same is true with the rapid evolution of disease
diagnostics. New, more sensitive tests, and testing in
previously impossible circumstances are generally
desirable activities, but what can or should one do
about interpreting and acting on the results?
The increased intensity of research into
Mycobacterium avium subspecies
paratuberculosis (MAP) infections in domestic and
wildlife species, and concern about the zoonotic
potential of MAP organisms is leading to new information
on the distribution of this organism in wildlife and
natural ecosystems. MAP DNA has been identified in fecal
samples from free-ranging and captive Wood and Plains
bison in northern Canada, without signs of clinical
disease.
A
workshop, entitled Mycobacterium avium subsp.
paratuberculosis in North American Bison (Bison
bison) was held in Edmonton, Alberta, on Friday,
February 18 and Saturday, February 19, 2005. Invitees
included scientists, veterinarians, wildlife and
agricultural workers and managers, and students from
universities, institutes and governments in Canada and
the United States. Following an information session, the
group discussed how to assess the risks and consequences
associated with this discovery and the implications to
wildlife management and translocation activities.
The
results of the workshop are contained in this report.
Key research needs include better surveillance to
determine the distributions and prevalence of the
organism in wood bison across Canada, identification and
characterization of this organism (by culture), and
determination of the significance of this organism to
wood bison health at an individual and population level.
The need remains to follow up on these plans: this will
require a collaborative effort between the varied
stakeholders involved in wild bison conservation and
wildlife disease research, and the identification of
research funding to commit to this work.
About
this report…
This
workshop summary and report was funded by the British
Columbia Ministry of Environment and was compiled from
material provided by several workshop participants.
Michele Oakley from the Department of Environment,
Government of Yukon and Helen Schwantje took notes
during the workshop, which are paraphrased here, and
Jenny Powers, Wildlife Veterinarian, U.S. National Park
Service, provided an initial summary. Material from some
of the PowerPoint presentations used at the workshop is
included. The Department of Veterinary Microbiology at
WCVM kindly granted permission to use portions of an MSc
thesis by Jennifer Sibley as background information on
MAP and fingerprinting methods. Sincere thanks to all
who provided material and participated in the workshop.
