Termite/Rats Attic and Crawl Space Vents
Termites come in from under ground so no, screens will do 0 good. But you do need to get this house inspected ASAP. Any pest control company can check out the whole thing for free.
Do you even know what to look for when it comes to Termites? There living inside the wood and when they travel out side of the wood they have to make mud tunnels.
If there all the way up into the attic your in deep dodo. It would have taken them at least 20 years to have been able to have eaten there way that high.
I would be loading up that crawl space and attic with glue traps and Decon.
A rat population can double every 30 days.