from my experience, as reported in a different thread, I'm fairly certain I got bitten while snoozing transpac upstairs on a UA 747 flight NRT-LAX in the new config lie-flat business seats.
At least that's where I assume the bites happened since I noticed them immediately after arriving home; my travel companion was not affected.
At least one other poster contributed a similar experience, egad!
In the past we'd stayed at the same hotels as before and after this particular flight and NEVER had a problem in the past.
Never felt the bites on backs of legs mostly, no itch, no scratch, just raspberry-colored, random spots that weren't there when I started out...