Invasion Science and the Global Spread of SARS-CoV-2
M.A. Nuñez, A. Pauchard, A. Ricciardi
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Invasion Science and the Global Spread of SARS-CoV-2
Authors: M. A. Nuñez 1*, A. Pauchard2,3, A. Ricciardi4,5
1Grupo de Ecología de Invasiones, INIBIOMA, CONICET, Universidad Nacional del
Comahue, Pioneros 2350, San Carlos de Bariloche 8400, Argentina.
2Laboratorio de Invasiones Biológicas, Facultad de Ciencias Forestales, Universidad de
Concepción. Victoria 631, Concepción, Chile.
3Institute of Ecology and Biodiversity (IEB), Chile.
4Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec
H3C 0C4, Canada
5Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch
University, Matieland, South Africa
*Correspondence to Martin A. Nuñez, firstname.lastname@example.org
Emerging infectious diseases like COVID19 are driven by ecological and
socioeconomic factors, and their rapid spread and devastating impacts mirror those of
invasive species. Collaborations between biomedical researchers and ecologists,
heretofore rare, are vital to limiting future outbreaks. Enhancing the cross-disciplinary
framework offered by invasion science could achieve this goal.
Key words: Biological Invasions; Novel Pathogens; Invasion Science; Globalization;
Biosecurity; One Health
SARS-CoV-2 as a biological invasion
A sinister combination of ecosystem alteration, wildlife exploitation, and global
connectedness is increasing the risks of novel infectious disease emergence and spread
[1,2]. This combination of factors goes far in explaining recent viral epidemics and
pandemics such as SARS-CoV-2 (the virus responsible for COVID19 disease; 2019–
ongoing), Zika (2015–16), H1N1 (2009), and SARS (2002–04), and forewarns of others
in the future. Accordingly, societal efforts must be directed toward managing not only
the pathogens themselves but also the environmental factors that facilitate their
emergence, spread, and impacts. In addition to resolving the immense socioeconomic
and cultural challenges to this goal, clearly we must develop a cross-disciplinary
research program to address the consequences of increasing global connectedness and
alteration of biological systems. This collaborative effort must include the study of
biological invasions – the spread and proliferation of organisms in new regions.
SARS-CoV-2 should be viewed as a biological invasion, although infectious
human diseases are rarely treated as such. Despite the longstanding debate on how to
classify viruses as living organisms, this viral outbreak has traits typical of an invasive
species: sudden emergence, rapid proliferation and spread, adaptation to new
environments (or hosts), large-scale geographic dispersal via human transportation
networks, and significant impacts – in this case on human health and well-being. Its
management requires consideration of stage-based processes and expansion phases
quite similar to those of invasions of non-pathogenic organisms (Figure 1). Thus, we
contend that the field of invasion science  is positioned to contribute substantively to
understanding the drivers and mechanisms of the spread, and factors promoting
outbreaks, of novel infectious pathogens like SARS-CoV-2.
The spread of novel organisms and the role of invasion science
Invasion science inherently examines the connectedness between natural and
anthropogenic systems by integrating perspectives of, inter alia, ecology, biogeography,
population dynamics, evolutionary biology, risk analysis, human history, and
environmental management to understand the spread and impact of introduced
organisms in non-native contexts. The study of invasions has traditionally focused on
species per se, but ecologists have advocated extending its focus more generally to
hybrids, microbes, viruses, genetically modified organisms, and synthetic life, which are
all subject to biological constraints, evolutionary change, and opportunities to interface
with global transportation networks [3–5].
A major insight from invasion science is that the co-evolutionary relationships
between introduced organisms and their environments is key to understanding their
invasion success and impact [5,6], with novel organisms – those without evolutionary
analogues in their recipient environment – having the greatest potential to cause
disruption [5–7]. The introduction of novel organisms can create evolutionary
mismatches in which members of the recipient community have no adaptations to these
organisms and thus are highly vulnerable to their impact; the analogy to disease
immunology is evident.
It is not known what proportion of introduced novel organisms will proliferate
and cause substantial damage. Many have subtle or apparently minimal impacts on their
environment. Others can remain innocuous for periods of time before suddenly
becoming invasive (or virulent) in response to environmental change. Biological
invasions are growing in frequency worldwide , and the impacts of even a small
proportion (but an escalating absolute number) of these can be so disruptive and costly
that the issue is of societal importance, including to human health and well-being . At
a time of unprecedented globalization, managing the threat of invasive novel organisms
requires internationally coordinated rapid response plans. Poor preparedness and
delayed response to invasions can lead to inadequate biosecurity measures and
potentially devastating costs, as the world has witnessed with SARS-CoV-2.
A cross-disciplinary approach to biosecurity
We believe the COVID-19 pandemic can provide a powerful impetus for
ecologists, epidemiologists, sociologists, and biomedical researchers to develop an
expanded invasion science that makes broader contributions to global biosecurity by
embracing the philosophy of the One Health Initiative – whose goal is to achieve
optimal public health outcomes by monitoring and managing the interactions between
humans, animals, and their environment . Burgeoning studies have combined
wildlife epidemiology with biogeography and community ecology, and ecologists
recognize the compatibility of concepts of disease ecology and biological invasions
[11–13]. Indeed, ecological research has revealed complex, indirect effects that
invasions can have on human disease risk [9,14]. Invasion science, a broad field
devoted to understanding the processes behind the spread and impact of novel
organisms, is positioned to help prevent, control and potentially eradicate harmful
invasive organisms such as SARS-CoV-2, thereby allowing a more sustainable human
existence within an increasingly altered natural world.
Biomedical research on emergent infectious diseases would benefit from what
invasion science can offer in terms of, for example, 1) a consolidated array of
frameworks for studying the consequences of eco-evolutionary novelty, and specifically
the release of organisms lacking ecological analogues in their recipient environments
; 2) expanding knowledge of the eco-evolutionary factors that determine the success
of transitions between stages of invasion (Figure 1), which are influenced by a
combination of human activities, environmental conditions, and their feedbacks
[4,11,12]; and 3) a rich literature on the context-dependent dynamics and predictive
modeling of organismal spread and their effects.
However, although some invasion biologists have advocated greater integration
of their field with human epidemiology, published evidence of cross-disciplinary
research applied to emergent infectious diseases remains relatively meager. Ogden and
colleagues  noted the scarcity of examples where the application of human
epidemiology to biological invasions or invasion biology to emerging infectious
diseases has resulted in improved prevention or control. Undoubtedly, there is a need
for further advancement of cross-disciplinary approaches toward applied research and
management of invasive human pathogens.
Owing to international sharing of spatiotemporal data, the spread of SARS-CoV-
2 is the most meticulously mapped biological invasion ever documented on a global
scale . This unprecedented rapid sharing of information, particularly from the early
stages of an invasion is not only an extraordinary opportunity for advancing the
frontiers of invasion biology and epidemiology, but also demonstrates the potential for
global cooperation in biosurveillance of all types of novel organismal threats. Emerging
infectious diseases and invasive organisms in general are increasing in frequency with
no sign of saturation [2,8] and their prediction, prevention, and control are a societal
priority. A cross-disciplinary invasion science offers valuable underexploited
frameworks and insights that can facilitate such initiatives and we hope the COVID19
pandemic will serve to catalyze greater collaboration.
Acknowledgements: We thank two anonymous reviewers for helpful comments and W.
Policelli for help with the figure. AP funded by CONICYT PIA AFB170008
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Figure 1. Stages of a zoonotic viral epidemic compared with those of a biological
invasion. Similar stage-based processes affect the spread of infectious zoonotic
pathogens (such as SARS-CoV-2) and non-pathogenic invasive organisms,
demonstrating the need for a common set of international management actions (e.g.
early detection, rapid response, eradication or containment, mitigation) appropriate to
each stage of the process.