I spoke with the lab. They had some interesting things to say.
First, they mentioned this is a preliminary report. Apparently one of the problems is that microbes tend to have a fairly low abundance in blood, and bacteria can have quite large genomes made up by a huge number of fragments. As a result, the bacteria with a relative abundance of around 1% would have a lower specificity than those with an abundance of around 10% or more. (Viruses, on the other hand, have much smaller genomes, so tend to have a high degree of specificity).
They are currently in the process of upgrading the bioinformatics procedure that they apply to the raw data, which they believe will give the lower abundance bacteria a greater degree of specificity. So they suggest I hold off on reading too much into those bacteria until we can crosscheck them against a new report, which they hope to have to me by next week.
The cicada bacteria is not something they have come across before (unsurprising). The person I spoke to at the lab (I believe one of the co-founders of the company) said that she would have a look at the research on that microbe if it comes up again in the next report.
Regarding your question,
@Hip: apparently you should not expect to see viruses in the blood unless there is an active infection and they are replicating. Of course this only takes in DNA viruses, so there could be an RNA virus in my blood.
Apparently they would not expect to see the fungus Malassezia Globosa in the blood sample of a healthy person, but they do come across it fairly regularly in unhealthy people, which I find interesting.
There are of course no firm answers here - I didn't expect there to be unless something really obvious like borrelia popped up - but there is definite food for thought nevertheless.
I will write to my GP to see if he'll refer me to an infectious disease specialist. However I am sure you can all appreciate that the likely outcome of an appointment with an ID specialist is a vexed doctor who recommends I speak with a psychiatrist.