Connecting Global Priorities Biodiversity and Human Health

disease concern for humans as well a mammalian
domestic animals and wildlife, killing over 50 000
people annually worldwide, necessitating ongoing
vaccination and/or population control methods
in domestic animals, and causing major declines
in some wild canid populations (e.g. African
Wild Dog and Ethiopian Bale Wolf populations).
Moreover, disease spill-over is not one-directional;
wild and domestic animal populations may acquire
disease directly from human contact. Integrated
surveillance and control campaigns may be costeffective
means for the early identification of
threats before they harm humans, domestic
animals, or wild species (Machalaba and Karesh
2012).
3.4 Systems approach and collaboration
While most emerging diseases originate in
wildlife, sustained infections are commonly
transmitted among humans or through a domestic
animal connection (Kock 2014). For example,
HIV originated in non-human primates, but
its principal ongoing transmission source for
new infections is human–human. However,
given the population impacts of HIV and other
diseases that have emerged from wildlife, there
are opportunities to move upstream toward
more preventive efforts for future disease while
still focusing on mitigating impacts of current
ones. Vector-borne disease will always be a
challenge for control from ongoing movement
across boundaries (but it is the vector, and not
wild host, which matters here) and attempts to
eliminate vectors are frequently ineffective or
lead to unintended and detrimental ecological
consequences. Despite this, the main concern
related to biodiversity and emerging disease
remains the spill-over of microorganisms from
wildlife into human-modified landscapes where
the organisms occasionally evolve into pathogens
(e.g. corona and influenza viruses). Importantly,
the evolution of these pathogens is largely driven
by the human system itself (landscape, domestic
animals, artificial habitats, behaviour) and through
peri-domestic wild species that have adapted to
the modified landscape (Kock 2013; Jones et al.
2013). Infectious disease funding streams are
currently heavily directed toward human–human
prevention of new cases, but dedicating a small
portion of funds to preventing future disease
emergence could yield downstream cost savings.
To tackle the issues described above requires a
highly collaborative and interdisciplinary, systems
approach. But, the big question is, where to start?
There is currently no reliable toolkit to accurately
determine which of the candidate infectious agents
will emerge as pathogens. Given limited resources
and millions of potential species and billions of
potential strains of micro-organisms, starting
efforts might be targeted to detecting pathogen
families that are known to be highly pathogenic to
humans and other species and taking preventive
measures, and refining risk analyses for wider
pathogen pools as more knowledge is generated.
In light of this evidence, measures and policies to
reduce risk of spill-over should include:
• On a precautionary principle, avoidance of
high-density monoculture agriculture and human
activity/settlement adjacent to highly biodiverse
ecosystems (especially urban centres, mining,
industrial and intensive livestock systems).
• Utilization of an ecological or “One Health”
approach to disease, rather than a simplistic “one
germ, one disease” approach to provide a richer
understanding of human, animal and environment
health links.
• High biosecurity of all industrial and intensive
animal and plant agriculture, and more judicious
or prudent use of antimicrobial agents in both
human and animal medicine and food production
systems to reduce selection pressure for evolution
of resistant strains.
• More resilient diverse agriculture and
sustainable harvesting systems. In the case of the
latter some species are high risk for pathogens
and should not be included in the human diet,
e.g. non-human primates given their high
genetic relatedness to humans (additionally, they
constitute an unsustainable protein source). For
example, the origin of the 2014 human Ebola
outbreak in the Democratic Republic of Congo
was linked to the butchering of an infected
148 Connecting Global Priorities: Biodiversity and Human Health