Experts say there is a clear upward trend in the number of viruses moving from animals to humans, and further outbreaks are likely if no action is taken.
The world has witnessed a rise in diseases caused by viruses that have jumped from animal hosts to the human population, with COVID-19 just one example, experts have said in a new report.
Ebola and MERS, as well as the West Nile and Rift Valley fevers, were other examples of zoonotic diseases that are being driven by the degradation of our natural environment, the UN Environment Department (UNEP) and International Livestock Research Institute (ILRI) said.
"While many in the world were surprised by COVID-19, those of us who work on animal disease were not," lead author of the report Delia Randolph said.
"This was a highly predictable pandemic," the ILRI veterinary epidemiologist Ms Randolph said.
Professor Randolph described a "very clear trend" since the 1930s that shows 75 per cent of emerging human diseases stem from wildlife.
COVID-19, for example, most likely originated in bats, according to UNEP and ILRI.
Further outbreaks will emerge unless governments take active measures to prevent other zoonotic diseases from crossing into the human population, UNEP warned.
The report, released on Monday, identified seven trends driving the prevalence of zoonotic diseases.
The trends included increased demand for animal protein, a rise in intense and unsustainable farming, increased use and exploitation of wildlife, and climate change.
"The science is clear that if we keep exploiting wildlife and destroying our ecosystems, then we can expect to see a steady stream of these diseases jumping from animals to humans in the years ahead," UNEP executive director Inger Andersen said.
Protecting the environment can help to prevent another global outbreak like the COVID-19 pandemic, as it was often human activity that was breaking down natural barriers that used to protect humans from disease pathogens, the UNEP reported.
The report said every year, some two million people, mostly in low- and middle-income countries, die from neglected zoonotic diseases.
In the last two decades alone, zoonotic diseases have caused economic losses of more than $US100 billion, not including the cost of the COVID-19 pandemic, which was expected to cost $US9 trillion over the next few years, the UN said.
African countries - a number of which have successfully managed zoonotic outbreaks - have the potential to leverage this experience to tackle future outbreaks, ILRI director General Jimmy Smith said.