The transmission from animals to people of the virus that causes COVID-19 has taken the world by surprise, but it should not have done.
In their report “Connecting Global Priorities: Biodiversity and Human Health” published in 2015 , the Secretariat of the Convention on Biological Diversity  and the World Health Organization  reviewed among other things the state of knowledge of links between biodiversity, ecosystem stability, and epidemic infectious diseases.
They explained how, in Malaysia, deforestation and intensified agriculture enabled the movement and mixing of species and the resulting opportunity for pathogen transmission. In Bangladesh, human demand for natural resources through tapping into trees for sap enabled a new food source for bats, similarly providing pathogen mixing opportunities that can be detrimental to people and domestic animals and potentially wildlife through conflict with humans given health and livelihood risks.
In addition land-use change and other changing ecological scenarios in one region may have unanticipated effects in another region through species range adaptations and other factors. Climate change scenario models have suggested that increasing temperature may enable spread of the bat species that harbour viruses.
And they told how Nipah virus, for which fruit bats are a natural reservoir, emerged in humans in Malaysia following conversion of forest to an intensive swine facility that enabled bat–swine contact, and subsequently transmission from pigs to humans. Several significant zoonotic infectious diseases have emerged in part due to the substantial human–animal contact that occurs along the wildlife trade chain, from harvest to end point. These diseases have included SARS coronavirus (wet markets in China), HIV (primate bushmeat hunting), monkeypox virus (exotic pet trade), and H5N1 and H7N9 avian influenza viruses. The global trade in wildlife provides disease transmission mechanisms that not only result in human and animal health threats but also damages to international trade, agricultural livelihoods, and global food security.
Now, following the COVID-19 pandemic, numerous warnings that this will happen again unless man’s relationship changes by the UN Environment Programme, WWF and others. Perhaps now our political leaders have learned that ignoring such warnings is far more expensive than taking action.