The novel coronavirus originating in Wuhan (2019-nCoV) is a zoonotic disease. It is an infection that has passed from animals to humans.
Humans have not developed immunity to such infections. That in turn means they are often more deadly, and spread rapidly.
According to the World Health Organisation, new zoonotic infections are becoming more frequent because of climate change and other human behaviour.
Zoonotic diseases are more likely to occur when populations of animals and humans that do not normally interact come into contact with each other. Climate change makes this more likely in a