Coronavirus is telling the world what we have been saying for many years: if we do not protect biodiversity and nature, we will face further and worse threats in the near future
The current SARS-CoV-2 coronavirus pandemic offers the starting point to examine the current relationship between man and nature at a global level, and how this cannot be discussed in isolation from the health aspects related to the emergence of new viruses and pathogens with pandemic capacity (1).
An in-depth analysis of the WWF (1) illustrates in a detailed and holistic approach how environmental changes related to human activity favor the emergence of new pathogens in wild populations and their link to humans.
Many of the so-called emerging diseases such as Ebola, AIDS, SARS, MERS, Nipah virus, Hendravirus, avian influenza, swine flu and today the new Coronavirus (SARS-CoV-2 previously defined as CoVID-19) are not random events, but the consequence of the impact of human activities on natural ecosystems.
With his activities, man has significantly altered three quarters of the land and two thirds of the oceans, changing the planet to such an extent as to determine the birth of a new era called "Anthropocene".
In recent decades, the passage of new viruses from wild reservoirs into the human population is supported by a number of factors, including the presence of markets in Asian or African metropolises where illegal or uncontrolled trade of live wild animals (monkeys, bats, snake meat, pangolin flakes, and many other reptiles, mammals and birds) and their products (meats and preparations for traditional medicine), is practiced.
Furthermore, the deforestation of vast areas of virgin forest for the intensive production of vegetable products (i.e. palm oil), or to provide pastures intensive and extensive breeding livestock, often create the conditions for a close encounter between man and wild animals. This generate dangerous opportunities for contact between humans and microorganisms, habitual hosts of wild animals, favoring the emergence of new zoonoses.
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This brief "review" on these subjects aims to try to gather the main considerations and opinions of experts in various scientific, economic and social sectors. Moreover, it try to explain the links between human actions on natural habitats, climate change and biodiversity and the consequences that these have brought on the possibility of the onset and spread of new pathogens dangerous for public health and on the socio-economic limits of our societies.
The appearance of new pathogenic viruses for humans, previously circulating only in the animal world, is a phenomenon widely known as "spillover" (in current use in ecology and epidemiology "spillover" indicates the moment when a pathogen from one host species moves into another species).
In the case of SARS-CoV-2 the origin of the virus is not fully proven, even if it is believed to derive from viruses present in species of bats, based on the strong similarity of the genome of SARS-CoV-2 with that of two coronaviruses isolated in bats in the past (2).
It is also unknown the exact time in which SARS-CoV-2 infected man for the first time and whether other animal species have been involved.
In any case, the large animal market in Wuhan, in the Chinese province of Hubei, where for the first time, in December 2019, SARS-CoV-2 infection was detected in humans, certainly represented an important moment of amplification of the infection in the human population, with the establishment of an efficient inter-human transmission of the virus.
If today the origin of SARS-CoV-2 is still uncertain, there is greater certainty, however, on what are the main risk factors for the spread to humans, related to the often illegal trade of live wild animals and of their products.
Of all the emerging diseases, zoonoses that find their origin in wild animal species could represent in the future the most significant threat to the health of the world population (3). The 75% of the known human diseases derive from animals and, the 60% of the emerging diseases are transmitted by wild animals. Zoonoses cause approximately one billion cases of disease and millions of deaths each year (4).
Emerging zoonoses are those that concern humanity most because they appear at an unprecedented rate in our human history and because they have an important impact on human health, on the social and on the economic systems. These zoonoses are the most dangerous because with billions of human beings who gather, socialize, travel and work, they can give rise to real epidemics if not pandemics; the whole is favored by the growing globalization.
For example, compared to about 9,000 infected people, the economic loss, due to the SARS epidemic in 2003, cost to the global economy about 30-50 billion dollars (1).
According to some scientists we are facing a new "epidemiological" situation in which globalization, with the growing movement of people and goods, is accompanied by the more frequent onset of new and old diseases, placing national and international health systems in extreme difficulty in containing the spread of these pathogens.
Recent research has linked the alteration of ecosystems with the onset and spread of infectious agents and new zoonoses. Scientists around the world are aware that among the causes of the spread of emerging infectious diseases, such as Ebola, Marburg hemorrhagic fever, SARS, MERS, Rift Valley fever, Zika and many others, there are important factors such as the loss of natural habitats, the establishment of artificial environments, the handling and trade of wild animals, and more generally, the wrecking of biodiversity (5).
If on the one hand the spoiling of habitats and biodiversity creates favorable conditions for the spread of emerging zoonoses, on the other hand the establishment of artificial habitats with high human density e poor in natural habitats can further facilitate it. Intensive agriculture, deforestation, habitat fragmentation, intensive use of antibiotics, medicine and pesticides, uncontrolled urbanization of forest areas, etc., are all factors capable of seriously disturbing the balance of ecosystems, populations and individuals capable of contrasting the microorganisms responsible for some diseases (6).
Consequently, better comprehending the functioning of ecosystems, and in particular their crucial role that they play in defending us from the spread of diseases, is fundamental to understanding the importance of protecting and managing them more adequately, avoiding having to run for rebuilding and restoring ecological balances and processes crucial for human health.
The growing human population, which today has almost reached 7.7 billion, and the rapid growth in per capita consumption of goods and services, which together determine humanity's growing ecological footprint, are altering the planet's land cover, the rivers and oceans, the climate system, the biogeochemical cycles and the functioning of the ecosystems.
The 2019 report of the IPBES (Intergovernamental Science-Policy Platform on Biodiversity and Ecosystem Services of the UN), which is the most authoritative and recent report on the state of planetary biodiversity, shows that 75% of the Earth's environment and approximately 66% of the marine environment have been significantly modified. Moreover, about one million animal and plant species risk extinction (7).
Furthermore, the Living Planet Report written by WWF in 2018 informs that the planet has lost on average 60% of vertebrate populations in just over 40 years (8).
Land use changes and the destruction of natural habitats - such as tropical forests - are believed to be responsible for about half of emerging zoonoses (9).
As David Quammen writes: "Where the trees are cut down and the fauna killed, the germs of the place find themselves flying around like dust rising from the ruin" (10).
The trade in wild species and direct contact with parts of animals exposes humans to contact with viruses or other pathogens of which that animal can be a host. Bushmeat consumption is growing dramatically in many parts of the world.
Bushmeat is consumed directly in the forests, but it is also transported to the countryside and cities. In some cases, what are considered delicacies, like unfortunately monkey meat, follow real illegal trade routes even between distant countries.
Just as hunting wild animals and bushmeat consumption can pose serious risks to human health, the same is true of the widespread wildlife trade or parts of animals: the wildlife trafficking. The wildlife trafficking and of plant species is not only one of the main causes of loss of biodiversity (i.e. the illegal trade in rhino horn or pangolin scales), but it can be an important mechanism to spread zoonotic diseases.
Wild animals of all kinds travel along the commercial roads that connect continents and distant countries, potentially amplifying the spread of pathogens. Farmed or wild animals have enormous potential to transmit viruses. They can in fact scratch, defecate, urinate, cough, infect each other or, in a more or less relevant way, infect humans. Furthermore, the close proximity of different species facilitates genetic recombination of different viruses and the spillover between species.
Environmental policies must promote suitable land use plans, reduce deforestation and contact with potentially hazardous animal species. Ecosystems maintain an irreplaceable role in the regulation of diseases; they guarantee a perfect biological dynamic that reduces the probability of transmission of pathogen to humans.
Although the fundamental and priority objective is still maintaining the vitality of natural systems in order to preserve their evolutionary capacities and their dynamics, it is also necessary to proceed with actions to re-establish and to restore the functions, processes and dynamics of these extraordinary systems that nature has designed in billions of years of evolution. We must start real works of "re-establishment" of the ecosystems that we have destroyed and degraded. Aware of this difficult challenge, the United Nations has decided to dedicate this decade to Ecosystem Restoration.
“We all depend on healthy ecosystems for food and energy, water and biodiversity. Their continued degradation contributes to climate change and increases the risk of serious ecological disasters. . The widespread loss of functionality of terrestrial and aquatic ecosystems will be catastrophic for our planet and will represent a huge step backwards compared to the progress made towards achieving the United Nations' Sustainable Development Goals. It is time to rebuild what has been lost“ (11).
The program is based on 17 global objectives, conceived as the ideal continuation of the Millennium Goals, approved in 2000 to be completed this year (only part of the commitments has been respected). The new targets were divided into 169 specific objectives. The first is "to eliminate poverty in all its forms". Therefore, the key points of the program include issues such as health, access to education, the decrease of inequalities and the promotion of women, as well as the fight against climate change. It is a promise made by the state officials to the population of the whole world.
Understanding the functioning of ecosystems, and in particular the role that biodiversity can play in decreasing the probability of spreading diseases, is very important to fully realize how the protection of natural habitats is not only a simple conservation objective, but a real measure of global healthcare. Managing natural habitats and ecosystems becomes crucial for guaranteeing and preserving human health.
“We must learn once and for all that the coronavirus pandemic is not something that has happened to us, but it is the result of the things we do, how we dominate the environment, the choices we make. We are all responsible for it and that if we want to be able to manage future epidemics we will have to change our perspective and think about solutions that take into account the fact that we live in delicate ecosystems of which man is part and not a stranger. The solution is obviously not to kill bats, but to leave them alone, because our ecosystems need them: they are important bio-indicators, essential for the maintenance of certain ecosystems, such as the tropics and deserts, through seed dispersal and pollination (10). “We must find a way to live in harmony with nature. Viruses have coexisted with wild animals for millennia their presence is nothing new. What has changed is the way we interact with wildlife: population growth, urbanization, intensive exploitation of natural resources and destruction of the environment have brought man more than ever in close contact with fauna and made it easier cross-species transmission”(12).
The solution, therefore, on paper would seem simple: "For zoonoses we must predict and control, we will never be able to eradicate them, except for the extinction of the animals in which these pathogens live. The most sensible suggestion is to leave these animals in their habitats, preserving and not destroying them", explains Professor Carlo Alberto Redi, zoologist of the University of Pavia and president of the Ethical Committee of the Umberto Veronesi Foundation. “Yet, the practical application of this concept appears to be very distant: our lifestyle is no longer sustainable from Earth: this is the reflection that politics must translate into actions from now on, for when we will go back out there with awareness, opening a real discussion on the causes of health and ecological crises. There are many points to work on; the respect for biodiversity and the environment, regulation of meat consumption, food education and control of commodity activities and hygiene of wet markets (those places where animals of very different species are piled up and waiting to be sold as food or therapeutic purposes), are the most urgent. Not only did we get this pandemic but also it was even well foreseen"(13).
In order to control or prevent zoonoses, the importance of following a "One Health" approach has become increasingly understood which recognizes how human health is closely linked to the health of animals and the environment. A strategic concept, formally recognized by many UN bodies, UNEP, UNDP, WHO, FAO, the World Organization for Animal Health (OIE), the European Commission, research institutes around the world, NGOs and other entities.
"One Health" identifies a holistic concept of people’s health, animals, plants, living and working environments and ecosystems, promoting the application of a multidisciplinary and collaborative approach to addressing potential or active risks that originate from interface between living and working environment, animal populations and ecosystems. "According to this approach, pandemics must be addressed with a multidisciplinary strategy, keeping epidemiology, climatology, species conservation, and risk communication together. Furthermore, the fight against epidemics will no longer be the sole responsibility of public health experts, but will require the collaboration of both public and private leaders, as well as the help of the general population"(12).
Therefore, to make the "One Health" approach truly effective it is necessary to establish a better and systematic interaction between professional groups, in particular between doctors and veterinarians, epidemiologists, ecologists and wildlife experts, but also sociologists, urban planners, economists and jurists. Only by recognizing that our health and well-being are closely connected to those of the nature that hosts us, can we guarantee our species from the most detrimental effects of pandemics (1, 14).
The conservation of biodiversity, the maintenance of habitats and health programs must be integrated into sustainable development plans, one as an essential part of the other. From this point of view, international organizations are already setting a good example, and local governments and authorities should hurry to follow it. An agreement called “One Health” between WHF (World Health Found), FAO (Food and Agriculture Organization of the United Nations) and World Organization for Animal Health has been stipulated for health policy; it which promotes new solutions that connect all relevant sectors for health and the environment, within a framework perfectly integrated into the objective 17 of Agenda 2030 (15).
“A final reflection should concern our lifestyle and the models that we have pursued to date. When we have overcome this phase of serious health, social and economic uncertainty, we should take the opportunity to reflect on our life style, on how we have exploited every resource on this planet so far, and rethink more sustainable production and consumption models. Environmental policies should be put in the foreground and decisions must be made which foresee the saving of the soil, the conservation of the landscape and a "reconciliation" between agricultural activity and the conservation of biodiversity "(16).
To achieve sustainable socio-economic development, society will have to pursue a combination of technological advances and sustainability, integrating the ever-growing need for food and energy with the need to preserve natural habitats.
The economic development model of many industrialized countries can no longer continue without posing the problem of environmental and health issues. Climate change and the risk of pandemics are two alarm bells that can no longer go unheeded, and the answers must necessarily be based on concrete actions to protect the environment, biodiversity and ecosystems.
References
- WWF Report 2020: Pandemie, l’effetto boomerang della distruzione degli ecosistemi (PDF)
- Lu R, Zhao X, Li J, Niu P, Yang B, Wu H, Wang W, Song H, Huang B, Zhu N, Bi Y, Ma X, Zhan F, Wang L, Hu T, Zhou H, Hu Z, Zhou W, Zhao L, Chen J, Meng Y, Wang J, Lin Y, Yuan J, Xie Z, Ma J, Liu WJ, Wang D, Xu W, Holmes EC, Gao GF, Wu G, Chen W, Shi W, Tan W. 2020. Genomic characterization and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet 395:565–574. https://doi.org/10.1016/S0140-6736(20)30251-8
- Jones et al., 2008. Global trends in emerging infectious diseases. Nature, 451, doi:10.1038/nature06536
- Morse et al., 2012. Prediction and prevention of the next pandemic zoonosis. Lancet, 380, 1956-1965
- Di Marco et al., 2020. Sustainable development must account for pandemic risk. PNAS, 117 (8), 3888–3892, doi/10.1073/pnas.2001655117
- Guide to the Millennium Assessment Report
- Global Assessment Report on Biodiversity and Ecosystem Services. IPBES, 2019
- WWF, 2018. Living Planet Report - 2018: Aiming Higher. Grooten and Almond (Eds). WWF, Gland, Switzerland
- Keesing et al., 2010. Impacts of biodiversity on the emergence and transmission of infectious diseases. Nature, 468, 647-665
- Quammen D., 2014. Spillover. L’evoluzione delle pandemie. Adelphi. 608 pp, ISBN 8845929299
- https://www.decadeonrestoration.org/
- https://www.valigiablu.it/coronavirus-pandemia-cambiamento-climatico/ Valigia Blu Ilaria Di Silvestre
- Intervista al professor Carlo Alberto Redi, zoologo dell'Università di Pavia e presidente del Comitato Etico di Fondazione Umberto Veronesi: Una pandemia ampiamente prevista e procurata dal comportamento dell'uomo
- WWF 2020: Biodiversità e Pandemie
- Mark Stafford-Smith et al. 2017. Integration: the key to implementing the Sustainable Development Goals. Sustainability Science volume 12, pages 911–919
- Phalan B. et al., 2011.Reconciling Food Production and Biodiversity Conservation: Land Sharing and Land Sparing Compared. Science, September 2011. DOI: 10.1126/science.1208742.
Francesca Dall'Acqua
Centro Operativo Veterinario per l'Epidemiologia, Programmazione,
Informazione e Analisi del Rischio
Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale"
