Is it possible for one family to have such a severe infestation of a microscopic bug of some sort that every time they visit someone elses house it seems the 'bugs' reinfest the house they visit so rapidly? Treatment (with permethrin or pyrethrin (whatever that ingredient is), vacuuming and washing bedding, towels, etc used in borax) has been effective every time so far but reinfestation seems to happen every time and that is simply confusing, I.e., does that mean the 'infestation' would be severe? If so, what type of microscopic bug is so highly contagious between people...and/or households? Thank you