Thousands of new viruses set to jump from animals to humans, study predicts

A warming climate shift of this magnitude will drive mass movement of wild animals as they seek to adapt to changing environments, the study said, while cautioning these kind of scenarios are most likely already underway.

Many animals will piggyback their parasites and pathogens into new zones, potentially setting off a viral and disease chain reaction.

Animal movement will mean species often encounter one another for the first time, researchers said, creating unique opportunities for viruses to transmit.

Using data models of mammal-virus networks and geographic range shifts for 3139 mammal species under climate change and land use scenarios for the year 2070, computer simulations established potential hotspots of future viral sharing.

Areas of high human population density in parts of Asia and Africa were flagged by the study, as were broad tropical regions where zoonotic spillover is known to most often occur.

Potential first encounters were “disproportionately likely” to happen in areas populated by humans or in cropland, the study said, findings at odds with previous theories which have claimed forests harbour most of the world’s emerging and undiscovered viruses.

Bats would likely be a key carrier and transmitter in the future, the study said.

“Because of their unique dispersal capacity, bats account for the majority of novel viral sharing, and are likely to share viruses along evolutionary pathways that will facilitate future emergence in humans,” the authors wrote.

“Surprisingly, we find that this ecological transition may already be underway, and holding warming under 2°C within the century will not reduce future viral sharing.”

Computer simulated models for the year 2070 highlighted the Sahel, Ethiopian highlands and Rift Valley, India, eastern China, Indonesia and the Philippines as likely “tropical hotspots of novel viral sharing”.

Researchers noted how simian immunodeficiency virus jumping from monkeys to chimpanzees and gorillas facilitated the origins of HIV in humans.

Similarly, SARS-CoV spillover into civets allowed a bat virus to reach humans, the study said.

“These kinds of wildlife-to-wildlife host jumps may be evolutionary stepping stones for around 10,000 potentially zoonotic viruses currently circulating in mammal hosts,” the researchers wrote.

The study urged greater surveillance and monitoring of the movement of different animals and their viruses to manage this risk.