For six months after, I was worried about possibly having brought the critters back with me to Germany.

And in the end, I did find one. Fortunately, I had followed the prescribed procedures. So when it emerged from some garments, it was inside a Ziploc plastic bag enclosing those garments. I was able to see it easily and kill it before it could turn my apartment into a living hell do its mischief.

We were watching a house for some friends while they were on vacation. They had cats. One day we walked in, and there were at least a million fleas hopping around everywhere. Since it wasn't our problem house, we backed out quickly, closed the door and called them to let them know what they were in for. If it isn't one thing, it is another.

I hope your treatment efforts were successful and that you really have eradicated them.

You don't mention obsessively researching the bugs and ways to protect yourself online as part of your reaction. I did that. What I found is that most of the practices used and recommended are based on 'best practices' established in the 1940s-50s and many still-recommended practices are of no use. (I really don't wish to bum you out, but I don't want you to think that useless methods actually work, either.) I did most of this research between 4-5 years ago, but the only change I expect between then and now is that the Bbugs have developed even better immunities to the pesticides used against them.

So that's the first thing: They are immune to the pesticides used against them. And,because they breed quickly, they continue to fine-tune their protections. In recent years, some neonicotines (yes, the neonics that have been devastating our bee colonies) have been given permits to be used against Bbugs (yet I did not find any records of successful testing against Bbugs). Imo, extending neonics to domestic use only creates another way for the neonics to be introduced to air & water, and thus to land. The MSDS I saw for a professional-use neonic stated plainly: HARMFUL TO MAMMALS (yes, in caps; also, such a straightforward warning of harm is very rare to find on an MSDS; also warnings about neurological and other organ damage, and danger to birds if the neonic enters water discharge; and it will kill cats outright because they do not have a gene which would allow their bodies to change the chemical to a safer form -- dogs have that gene.)

One thing that DOES kill them is direct contact with isoproyl (rubbing) alcohol, a 1:1 dilution of 70% alk (I used 90%) with water in a spray bottle can be used on hard surfaces (won't soak fabrics/furniture enough to reach them in their crevices). Fabrics (clothing) can be soaked in rubbing alk (I used straight 70%) and stored for a few days in (the Blue+Yellow=Green) zip bags with the air pushed out of them.

About 2 years ago I saw that naturally-occurring Neem Oil has been approved as a pesticide. You could research this for any negative effects (it has been used in India for time out of mind as a medicinal/cosmetic oil). You could look into the possibility of combining a little of it with water and a dash of dish soap (as a surfactant) and using it to spray or soak items. (NOTE that I am only suggesting a possibility, not making a recommendation.) I became aware of this through an article (on Wired, IIRC) about an already-available spray product using Neem Oil as its active ingredient. The article said that a laptop could be put in a zipper-bag along with some sprayed paper towels for a certain period of time (a few days) and any resident Bbugs would be killed (I seem to recollect also reading that books,shoes, etc could also be treated this way.)

Besides alcohol and (possibly) Neem, the only other thing that definitely kills them is heat -- exposure to 120F (40C) kills them instantly, slightly lower temps kill them with longer exposure. This exposes one of the weaknesses of the 'launder fabrics' part of standard practice: until/unless temps reach 120F, the Bbugs are only being treated to a Spa Day and, in trying to avoid the rising temp will scurry into the bowels of the machine to be transferred to other fabrics (or onto your arms when you reach in and they smell blood.) On the brighter side, a pre-heated drier can help. All but the most delicate fabrics will withstand a high-heat drier **IF the fabrics are BONE-DRY** when they go in. So it might work (with possibly-infected fabrics) to run a HOT cycle of the drier, put in the fabrics and run it HOT once or twice and then let them cool before washing and drying again.

There are companies now (or at least, tests were underway 5 years ago) which could bring furniture-size boxes to your home to use on furniture; and there are pest control companies equipped to heat-treat a home or apartment building.

Vaccuuming does nothing helpful. The Bbugs hide deep enough that for the most part the vac won't capture them , and the Bbug eggs are glued down. If your vac does capture some bugs, even if you immediately dispose of the bag, you run the risk of having some Bbugs make a home in the vac's parts. Brooms can also harbor the bugs, and transfer them to another location (the place you store your equipment).

Standard-practice instructions often warn about 'clutter', this, imo, is just another way to blame the resident An entire colony of Bbugs can set up camp in a space no thicker than a credit card, like the space between two linoleum tiles. I made a point of looking for something defining 'clutter' -- and found that the pest-control industry considers 'uncluttered' to be equivalent to an uninhabited hotel room, containing no trace of human habitation.

Bbugs have complicated life-cycles; they have five life-stages with a molt between each stage. The first 3 stages, they are very tiny and translucent so very hard to see. As they reach their 4th-5th stage, the shells harden and darken so they can be seen if you happen to find them in the open,which is rare. They avoid light, and if they are living in a mattress or furniture, they reach through the covering fabric to bite you, not coming out into the open.

They feed around every 3-5 days, and have to feed before they molt. If blood-meals are not available, they go into a kind of hibernation state -- and adult Bbug can survive for as long as 18 months without a meal. Any warm-blooded creature can provide them with meals, although (as of 5 years ago) veterinarian sites were still not saying the pets could be affected by Bbugs, common sense and the bugs' prehistory as living on birds strongly suggests that pets can be victims and hosts to Bbugs.

Although it's nice that you don't have the allergic reaction to Bbug bites that causes the bites to itch, in a way that's a disadvantage because (sorry to say this!) you home could be infested and you would have no way of knowing! A genetic setting determines whether or not a person is allergic (reactive), and among the general population of all ages the reactive vs non-reactive portions are about 50%. As you mentioned, research found that among people of ages 60 upward, many more were non-reactive (although the studies I saw were not clear whether the lower-reactive-ness was a function of aging or whether it was an attribute unique to that age-cohort at the time those tests were done).

So the useful bits I learned wee about rubbing alcohol, heat (120F or above), and possibly Neem Oil as the only way to kill them for sure, or keep items bagged up for at least a year and a half. The 'vaccuuming' and 'clutter' portions of the Standard Instructions are useless, as is the 'launder' portion unless you are sure that temps reach 120F (or leave washed fabrics bagged for a year and a half). You may want to consider getting an air mattress.

Good Luck!