They jump from one species of animal (dead or alive) to humans.
How can we pragmatically reduce the risk?
1. Ban markets where two different species are kept close to each other.
2. Identify species that are high risk. Ban eating them if they are not essential (other than domesticated animals).
3. For domesticated animals, have tough safety regulations.
4. For villages/cities near wild populations of high risk exotic animals (bats), have a system of monitoring.
5. Provide new jobs for people that are affected by the above restrictions so we don't drive them underground away from regulations.