As Earth's climate changes, animals that carry diseases are shifting their habitats in response — and changing the risk of infectious disease as they go.
Ticks, mosquitoes, and even smaller carriers like bacteria and algae are moving around as they adjust to rapid changes in temperature and available habitat. They may be corralled into closer contact with other species, or experience longer periods of warm months that allow them to flourish.
At the same time, human exploitation of natural resources and the sprawl of urban development is extending our reach into once-wild spaces.
COVID hit deer population, generating mutation passed on to humans
Officials said they sampled more than 11,000 deer and detected the virus in 12% of them, but even more had antibodies.
Together, these climate-driven shifts are causing new patterns of human disease.
The incidence of disease borne by infected mosquitoes, ticks and fleas tripled between 2004 and 2016, according to the Centers for Disease Control and Prevention. The World Health Organization estimates that malaria will contribute to a quarter million additional excess deaths from 2030 to 2050.
And experts warn climate shifts will likely affect the risk of diseases reaching pandemic scale.
"I think we’ve drastically underestimated not only how much climate change is already changing disease risks, but just how many kinds of risks are changing," Colin Carlson, a global change biologist at Georgetown University told The Associated Press. "I think there’s a lot more to worry about in terms of epidemic and pandemic threats."