Got chiggers once while backpacking in PA with my girl scouts. Our whole troop got them and it was very unpleasant, but we didn't do this extraordinary cleaning of our clothes and equipment. I just figured they were like any other bug in the weeds, bit you and move on; however, when we stayed in the cabins we did get a really nasty bug--bed bugs! and those came home with us. We had to clean our whole house and call an exterminator. The treatment OP went through sounds more like the bed bug treatment. Never, never want to go through that again. Chiggers are bad, bed bugs are worse. That was 2004 and I'm still paranoid if I have to stay someplace other than my 5er.