This is why all third class passengers were checked for lice before boarding Titanic to come to America. Most all Shipping companies did at the time.
Friends came back from a Russia last century and gave us a big hug. It took more than 6 months to get rid of the scabies infection. We cleaned ourselves, washed all clothes and bedding in very hot water. Then a child would find a jacket they had dropped behind the couch or something, wear it and again have scabies. What a nightmare of repeat attacks.