Insects that transmit disease will spread farther and transmit illness more quickly as the planet warms, according to experts at the Centers for Disease Control who monitor vector-borne diseases.

“[Mosquitoes] are really sensitive to climate change,” says vector biologist Lyric Bartholomay from the University of Wisconsin-Madison. “I don’t think there’s any doubt that as temperatures shift, their ranges and places they can go will also change.”

Last week, investment bank Morgan Stanley predicted that drug makers could see their profits soar in the coming decades as climate change exposes more than a billion people around the world to infectious diseases like yellow fever and dengue often spread by insects.

Here, experts explain how these little disease-carrying varmints are adapting to