Introduction
About 13 year ago experts in
virology have written in one of the most important microbiological scientific
journals the following recommendation: “The presence of a large reservoir of
SARS-CoV-like viruses in horseshoe bats, together with the culture of eating
exotic mammals in southern China, is a time bomb. The possibility of the
reemergence of SARS and other novel viruses from animals or laboratories and
therefore the need for preparedness should not be ignored” (Cheng et al. 2007).
Other Chinese scientists make today an explicit link between the current
pandemics and unexplained pneumonia patients in the Wuhan seafood market (Xu et
al. 2020). Such statements, and a lot of other sound scientific knowledge have
been ignored by the public, the decision makers and the states, leading to
losses of lives and an estimated global economic cost, at this moment, of about
5 trillions of dollars needed for recovery (G20 estimation), not to mention the
human lives.
A problem to be solved after we
get out of the current public health situation is how to improve the
rationality of decision making with respect to zoonotic epidemics, how to take
into account all relevant bodies of knowledge to prevent such crisis, and to
better manage them when the occur. In this text I will provide a potential
research framework and a syntheses of relevant scientific information. For our
scientific community and general public there are three aspects which will be probably
perceived as novel (although there is nothing novel from international
perspective):
·
Nature and biodiversity can be not only good,
but also bad, there are so called “ecosystem disservices”, of which zoonotic
epidemics are an example. These disservices depend to some extent on how we
manage the natural capital. The “good nature” image socially constructed after
the environmental crisis has to be adjusted;
·
Effective prevention of epidemics can be performed
only by a multidisciplinary monitoring
and research.
·
Efficient reactive management (control) of
epidemics can be done only by integrated
assessment of public health, economic social and defense risks, there is not one single most
important institution in this equation.
1 Potential research framework
The scheme below depicts a
potential complex long-term research project involving scientists, governance institutions
and other stakeholders, able to support decisions about zoonotic epidemics.
Cluster A it’s a matter of
management science, governance, political science, economy, institutional
analysis and development. I will not develop it, as it is outside my direct
field of expertise. Cluster be is a matter of integrated long-term research and
monitoring, a field similar with what is envisaged in sustainability
science. Actually, while the research in sustainability science is
traditionally focused on the “good nature”, here something accounting for the
management of one kind of ecosystem disservices should be developed.
Potential objectives in cluster B
(syntheses of relevant scientific knowledge in the next part of this text
1.
Mapping hotspots of viral sharing by birds and
mammals in Romania, in the frame of a process based accounting of ecosystem
disservices at national scale
2.
Modeling the effects of habitat fragmentation
and climate change on the dispersion of relevant vector species at regional and
macro-regional scale
3.
Accounting for the management practices
responsible for the increasing risk of viruses’ transfer to human populations.
4.
Construction of a data and knowledge transfer
interface from environment and sustainability studies towards the scientific
community of epidemiologist.
A full design of the research program
can be done by standard project management techniques (brainstorming with
inter-disciplinary teams, etc).
2 Short syntheses of relevant scientific
information
As the literature is huge in each
direction here I provide only a small sample of articles. In a project
management framework full critical analysis of the literature in each sub-field
will be a must before any decisions on the research design.
2.1. Epidemiology and causal complexity
Oosterbroek et al. (2016)
“mention the linear, reductionist approaches of epidemiology and public health
research in the second half of the 20th century, focusing on proximate
cause-and-effect relationships.” They state that “by training, epidemiologists
and public health re-searchers are less accustomed to studying causes within a
systems context or addressing long time frames. Most health scientists will
therefore not be familiar with the complex quantitative modeling approaches
that are developed by ecosystem scientists”
Nature can be both good and bad
for human health, by different processes: “The relationship between
biodiversity and infectious diseases is not straightforward; disease dynamics
are complex and dependent on the system, which includes the infectious agents,
their targets and hosts, their vectors, the environment (natural as well as
technological and sociocultural), and the mechanisms and interactions
connecting them” (Keune and Asmuth 2018).
“The need of prospective
scenarios of health that are embedded in the socio-ecosystems is crucial“: “Integrating
the various dimensions of complexity thanks to disciplines such as ecology and
environmental sciences, health sciences, policies and law, we analyze
retrospectively, and comparatively infectious diseases’ dynamics associated to
policies, land use and biodiversity changes.” (Lajaunie et al. 2019).
2.2 Ecosystem disservices and the role of
biodiversity in zoonotic epidemics
“Between 10,000 and 600,000
species of mammal virus are estimated to have the potential to spread in human
populations, but the vast majority are currently circulating in wildlife,
largely undescribed and undetected by disease outbreak surveillance.” (Carlson
et al. 2020). “Systematic effects of biodiversity change on infectious disease
could have enormous economic, public health, and conservation implications. As
examples, at least 60% of all human disease agents are zoonotic in origin”
(Young et al. 2016, and figure 2).
Figure 2 Left Animal
hosts of HCoVs from their natural
hosts (bats or rodents) to the
intermediate hosts (camelids, civets, dromedary camels, pangolins or bovines),
and eventually to the human population (Ye et al. 2020). Right Boxplots based on species‐level
data of proportion of viruses for several species in an order that are zoonotic
(Olival et al. 2015).
Birds can also be “carriers of
other organisms or their propagules” spreading “disease to humans and poultry”
and increasing the “incidence of human and livestock disease and death”; there
is a moderately negative valuation of birds by society, at a global scale of
relevance (Buij et al. 2017).
Disservices of nature like
zoonotic diseases are a kind of ecosystem disservices. Despite the large
scientific literature representations of ecosystem disservices are still
marginal in the public opinion (Lyitimaki 2014), because of the past
environmental crisis which led to an exaggerated shift towards completely
positive image of the nature (socially stabilized then by political ideologies
such as ecologism). There is an increasing trend for the integration of
ecosystem services and disservices provided by all parts of biodiversity (for
the case of plants see for instance Vaz et al. 2017). An example is provided in
figure 3.
Figure 3 Two examples illustrating the complexity of ecosystem –
health relationships when considering both ecosystem services and disservices
(Oosterbroek et al. 2016)
2.3 Human action on nature has consequences
on zoonotic diseases
“Changing climate and land use
drive geographic range shifts in wildlife, producing novel species assemblages
and opportunities for viral sharing between previously isolated species. In
some cases, this will inevitably facilitate spillover into humans —a possible mechanistic
link between global environmental change and emerging zoonotic disease”
(Carlson et al. 2020). Global effects on species diversity may lead to bottom
up effects on emerging diseases (figure 4). The fragmentation of natural
habitats is hypothetically related to infectious disease emergence (figure 4;
the real situation have to be checked in the case of each socio-ecological
system).
Figure 5 The framework linking the different aspects of habitat
fragmentation on biodiversity, is related to infectious disease emergence
through the two hypotheses: the “perturbation ” hypothesis and the “ pathogen
pool diversity” hypothesis (Morand 2018).
The increase in global
connectivity led to an increase in homogeneity of zoonotic diseases, i.e. in a
decrease in their modularity (the extent to which countries differ from one
another, figure 6)
Figure 6 Changes in the modularity of country infectious diseases
(Morand 2018).
2.4 Public health management as
socio-ecological management
Public health is connected with
livestock and wildlife health in the case of zoonotic diseases. “As a long-term
goal, public health systems can include paired human-wildlife surveillance
and utilize sentinel monitoring toward pre-emption of spillover in
humans. While these approaches will require upfront investments, cost-savings
can be seen from more integrated and more preventive approaches that
can benefit both human and animal health.” (Machalaba and Karesh 2015).
In ecology and sustainability science there are already general frameworks linking
the functioning of ecosystems and human health (figure 7)
„What is crucial is to find a relevant balance between taking into account
relevant complexity in order to not exclude important factors or actors, and on
the other hand, taking a pragmatic turn in order to be relevant for practical
action which cannot wait for perfect understanding” (Keune and Asmuth 2018).
In Romania one could adapt existing approaches for
multi-objective management and „lists of potential action categories considered
during each stage of pathogen emergence, with their expected
level of effectiveness and confidence in that effectiveness” (e.g. Grant
et al. 2017, figure 7). For the integrated implementation of such actions there
is a need for institutional coordination (e.g. between the USA Fish and
Wildlife Service, Department of Defense, and National Park Service, Grant et
al. 2017).
3 Conclusions
The huge global and local costs of ecosytem disservices like zoonotic
epidemics asks for future investments in trandisciplinary research involving epidemiologists,
experts from other disciplines, decisioni makers and stekeholders. At least two
cluster of sub-projects are needed: one for prevention, and one for reactive
management. There exists already plenty of scientific knowledge which have to
analysed, synthesized, and complemented with local research and monitoring in
order to build the integrated data and knowledge systems needed for an as
rational as possible decision making.
References (available
for download here)
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