Rat lungworm has a ground zero, Puna.

[Kenney]

Aloha glassnumbers. The map is somewhat helpful, however I doubt it tells the whole story. It only shows areas where the slugs have been tested.
And yes, 90% in Puna is a high number, thus Puna is ground zero for RLW in the US.
I think it's a good idea to just assume all slugs in Puna are infected and remain vigilant.
Better safe than sorry.