The worst thing about treating bed bugs is the time you spend wondering. Unfortunately, there is still a great deal we do not know about this re-emergent pest, but it is valuable to know where the uncertainties lie.

We can discover with 100 percent certainty that an account is infested; we cannot discover with 100 percent certainty that it is not.

This is not that different from termite work, where all you can do is a thorough investigation and report what you find. Even when using canine detection, light infestations may go undetected. The key is to communicate this with your clients so that their expectations of you are realistic. We can assume there are no bed bugs immediately after certain operations such as fumigation and heat treatment, but we cannot prove it.

Most infestations are established before they are discovered. This means that by the time you get there, the bed bugs have found harborage sites that suit them. It is the nature of the bed bug to choose harborage sites in a dark and quiet place not too far from their host. This should help us recognize that bed bugs found early in relatively shallow harborage are probably not the extent of the infestation. You will need to continue farther in and deeper down to achieve the best results possible.

This also means that in a multiple-unit dwelling situation such as apartments and senior housing, the units reporting bed bugs are only a portion of the problem. Therefore, a program that begins by treating only units that have reported bed bugs is treating only a portion of the problem. There are almost always units that have a light infestation unbeknownst to the tenants — and units that have heavier infestations unreported by the tenants. Infestations may go unreported for a variety of reasons. When inspecting an apartment where no bed bugs have been reported, yet you see a container of insecticide on the nightstand, you might consider the probability of infestation to be high.

New or overlooked?
We cannot tell the difference between a bed bug missed by the treatment and a bed bug freshly introduced. With the notable exceptions of fumigation and heat treatment for bed bugs, elimination after a single service is not the norm. It does occur, but can be neither predicted nor relied upon.

So what does the bed bug nymph you just found on a follow-up service mean? You can neither declare the treatment a failure nor assert that the bug was introduced from outside. The best course of action is to educate the tenant concerning our inability to determine and treat for the bed bugs. It is best to leave it in the realm of the unknown and continue the program until the premises are clear.

This concept can be taken too far, however: If on a return visit you find that the infestation is heavy and in the same harborages, you may want to change your treatment strategies.

Perhaps new research will reveal valuable insights into bed bug behavior and allow us to accurately predict their response to treatment — or even to confidently declare a room to be bed bug-free. Until that day, we can use the uncertainties to urge us onward and guide our decisions.