Mosquito-spread diseases may endanger millions in new places due to climate change

Study finds that places where people have never had the diseases could see bad outbreaks if they aren't prepared

Half a billion more people could be at risk from mosquito-transmitted diseases within 30 years as a result of the warming climate, according to a new study.

Canada and parts of northern Europe could be newly exposed to the threat. People there could come into contact with yellow fever, Zika, dengue and chikungunya, as well as other emerging diseases.