Hope your weekend is going well.
So...a jurisdiction is an area under the control or authority of one figure. A different jurisdiction means a different region with a different person/people in charge. In this text when they say jurisdiction, they seem to be indicating different countries.
When they say spillover they mean that a problem in one country will spill over or pour into the next country with very little control or anything we can do to stop it.
Essentially they're saying that the world is so connected now and countries share so many issues that a problem in one country, will very quickly spread to other countries. You could think of it as an economic virus or infection for example.
Hope that helps :)
PS: The Spillover Effect would be a good point to Google.