So diseases that were once under control are again on the rise across Germany (and other European States)? Over here, TB was all but eradicated but is now on the rise again.
Because people aren't vaccinating?
Unless you're referring to the fact that people travel a lot more now..(I'm being generous with the motives behind your post).
America has had several large oubreaks of some diseases, usually around tourist attractions or airports where the local population has decided they don't need an autism causing injection (insert huge roll eyes).
Oddly enough people who come from areas where the diseases are more common (or more recently eradicated) tend to be far more likely to take up immunisations, usually because they're aware of the dangers of the diseases pose, unlike someone who has never dealt with someone who has had the disease and instead read the scare stories in the papers, on the internet and listened to such world renowned medical experts as Alex Jones on the horrors of vaccines.
I've seen people (who presumably have had some education as they can read/write and use computers) not seeming to be able to understand how many people Polio killed and maimed despite it being eradicated in the US only about 50 years ago (and a lot of it's victims are still around), or the death toll of the flu before vaccines and modern healthcare was available.
Personally it's one of the situations where I think the state should have a major role in deciding what happens, as like the justice system it doesn't just affect the one person who has decided not to vaccinate their kids, or those kids, it potentially puts very large numbers of people at risk (those too young to have the vaccine, the elderly and those with weakened immune systems).