- Environmental experts said the emergence of SARS-Cov-2 was no surprise
- Zoonotic diseases, like Ebola, have soared in growth in the past century
- Zoonotic diseases are ones that can transmit from an animal to a human
- Experts say they stem from exploitation of wildlife, including demand for protein
- Two million people a year, mostly in poor countries, die from zoonotic diseases
Viruses jumping from animals to humans are becoming more common, the United Nations has warned.
The UN's environmental branch revealed that the emergence of SARS-CoV-2 — the coronavirus that causes Covid-19 — came as no surprise.
In a report, they said the pandemic was 'highly predictable' because human behaviour, including intense farming for meat, has triggered a surge in zoonotic diseases.
The United Nations Environment Department (UNEP) claimed the coronavirus most likely originated in bats.
Research has also pointed towards pangolins — which look like scaly anteaters — as a possible bridge between bats and humans. It may have evolved to become more infectious before bridging from the pangolin to a person.
A 'zoonotic disease' is one that is able to be transmitted from a vertebrate animal — such as a mammal, bird, reptile or fish — to a human.
Zoonotic diseases include Ebola, a killer disease that originated in monkeys, and MERS, another type of coronavirus linked to camels.
Experts say outbreaks among people tend to stem from human exploitation of wildlife, including intense battery farming and selling meat for food.
Every year two million people — mostly in poor countries — die of zoonotic diseases such as rabies, according to the UN report.
The Covid-19 pandemic has killed some 543,600 people globally in the eight months since it was formally identified. Millions have been infected.
The virus is considered to be zoonotic because it is believed to have first been caught by humans at livestock market in the Chinese city of Wuhan.
However, the jury is still out because the mysterious infection has only been known to science since the turn of the year.
The UNEP published the report on zoonotic diseases with the International Livestock Research Institute (ILRI).
Professor Delia Randolph, a veterinary epidemiologist and lead author of the report, said: 'This was a highly predictable pandemic.
'While many in the world were surprised by Covid-19, those of us who work on animal disease were not.'
Professor Randolph described a 'very clear trend' since the 1930s that showed that 75 per cent of emerging human diseases stemmed from wildlife.
Ebola, of which the largest global outbreak occurred from 2014 to 2016 and another in 2019, is one example.
Further outbreaks will emerge unless governments take active measures to prevent other zoonotic diseases from crossing into the human population, the report said.
Experts identified seven trends driving the prevalence of zoonotic diseases, which included 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,' said UNEP executive director Inger Andersen.
Destruction of animals' habitats forces them into closer contact with humans, raising the risk of disease transmission.
Climate change can contribute to this by making extreme weather events like flooding more common, driving animals out of their homes.
In Madagascar, for example, the bubonic plague is spread by rodents fleeing wildfires, which are becoming more common as the Earth heats up.
Human activity also often breaks down the natural barriers which protect humans from disease pathogens, according to the UNEP.
A major transmission route between the environment and humans is through the hunting and eating of wild, exotic animals.
Illegal wildlife trade can see a range of live animals, including bats, come into close proximity with people in markets.
Snakes, beavers, porcupines and baby crocodiles were among the species for sale at the Huanan Seafood Wholesale Market in Wuhan.
It is normal culture in China but there have been calls for the markets to be banned in order to protect wildlife and halt the emergence of zoonotic diseases.
Aside from lives lost, zoonotic diseases have caused economic losses of more than $100billion (£80bn) in the last two decades alone.
The cost of the Covid-19 pandemic — which is still rattling on and worsening in some parts of the world — is expected to cost $9trillion (£7.2tn) over the next few years.
African nations have the potential to leverage their extensive experience of zoonotic diseases such as Ebola to tackle future outbreaks, the UN said.
African nations combine public health, veterinary and environmental expertise and achieve faster responses to outbreaks, said ILRI director general Jimmy Smith.
Professor Randolph said: 'If pandemics can be caught right at the start, [studies have shown that] the costs can be reduced by 90 per cent.'