A study warns humanity must be prepared for thousands of new viruses and diseases that pass from animals to humans. Climate change causes this to happen easily in the next few decades.
A study by the University of Georgetown entitled Climate change increases cross-species viral transmission risk and published in Nature, reveals that at least 15,000 new cross-species virus transmissions will occur by 2070, if global temperatures rise by 2 degrees Celsius.
A warming climate shift of this magnitude would encourage mass movements of wild animals as they try to adapt to changing environments, the study said, warning that such a scenario was likely already underway.
Many animals will piggyback their parasites and pathogens into new zones, potentially triggering a chain reaction of viruses and disease. The movement of animals means species often encounter each other for the first time, creating unique opportunities for viruses to transmit.
The study predicts an increase in the number of infectious diseases emerging from animals to humans in the next 50 years, especially in Africa and Asia, due to this effect.
Using a data model of mammalian virus networks and shifts in geographic range for 3,139 mammal species under climate change and land use scenarios for 2070, computer simulations establish potential points for future virus spread.
Areas of high human population densities in parts of Asia and Africa are characterized by this study, as are the vast tropics where zoonotic spillovers are known to occur most frequently.
The potential for first encounters is "disproportionately likely" to occur in human-inhabited areas or on agricultural land, the study said. This finding contradicts previous theories that claimed forests harbor most of the world's emerging and undiscovered viruses.
Quoted from 9News, bats are likely to be the main carriers and transmitters of viruses in the future. That's because of its unique deployment capacity.
"Bats make up the majority of new virus carriers, and are likely to share viruses along evolutionary pathways that will facilitate future human emergence. Surprisingly, we found that this ecological transition may already be taking place, and holding warming below 2°C in this century would not be possible. will reduce the spread of the virus in the future," the researchers wrote.
Computer simulation models for 2070 highlight the Sahel, the Ethiopian highlands and the Rift Valley, India, eastern China, Indonesia and the Philippines as possible "tropical hotspots" for the new virus to spread.
The researchers noted how the simian immunodeficiency virus jumping from monkeys to chimpanzees and gorillas facilitated the origin of HIV in humans. Similarly, the spillover of SARS-CoV into ferrets allowed the bat virus to reach humans.
"This type of wildlife host-to-wildlife jump may be an evolutionary stepping stone for the approximately 10,000 potentially zoonotic viruses currently circulating in mammalian hosts," the researchers wrote.
The study calls for greater surveillance and monitoring of movement between different animals and their viruses to manage this risk.