The author, a former camp counselor, is very familiar with chiggers, also called harvest mites. They are common in woodsy areas, and they burrow into human skin and cause serious itching.
Rodents get chiggers and so do cats, especially cats who roam in the woods and fields. They are not dangerous, and the itch eventually goes away. The best thing about chiggers is that, unlike other mites, they can’t be passed from one host to another.