Lyme literate medical doctors (LLMDs) generally view Lyme as a clinical diagnosis. Getting a positive blood test is lucky (believe it or not) and associated with certain symptoms makes diagnosis much easier; but combinations of symptoms, the presentation of the disease, remembering a tick bite, or finding a tick on your body, developing a rash, or being/ have been in a Lyme-endemic area can also point to a diagnosis of Lyme.
Treating Lyme is even harder. In its early stages - for example in someone who finds a tick, develops the tell-tale bull's eye rash (indicative of Lyme, but not present in every case) and sees an LLMD early enough - Lyme can be treated effectively with 3-4 weeks of antibiotics. That's why awareness is so important.
In some unlucky people, a tick bite might not be noticed, or the rash might not develop, or might be on an area of the body where it is hidden (e.g. the scalp). Sometimes initial symptoms might seem like a cold or flu-type infection and nothing more. Spirochetes can lie dormant in the body for a long time, waiting on an opportunistic moment to launch an attack. It has been shown that bacteria in the body can communicate with each other and can 'tell' when there are enough to launch an attack. Sounds like a scary science fiction story? Absolutely! I was at a talk on Lyme last week and when the clinical immunologist giving the talk shared this piece of information people in the room gasped, horrified. I had actually recently read a news article that discussed research that claimed infections to be 'multilingual' i.e. different species can communicate with each other too. The science is here.
Borrelia is what is known as a stealth pathogen and is thought to be able to evade detection by the immune system in various ways - one way is by mutating into a different form (usually called L-form) ; this also makes it immune to most antibiotics.
Spirochetes can lie dormant and then attack when the body is weakened, perhaps by another infection (like the common cold) or by stress. When it gets to this stage, borrelia spirochetes have usually managed to 'escape' from the immune system by burrowing through tissue and moving from the blood vessels into different areas of the body. Microbiology research has captured this on video using powerful microscopes:
Another little horrifying piece of evidence regarding the adaptive ability of spirochetes. The voiceover in the video refers to no research being available on how spirochetes reproduce. I haven't heard or read anything about that anywhere, but the point of drawing attention to it here is really just to underline how little is known about borrelia.
The spirochete's DNA has been sequenced and it is the most complex bacterium currently known to man. Its DNA is 25% the size of human DNA which, apparently, is pretty significant.
Some researchers believe that many chronic, degenerative illnesses have borrelia as a factor - cause, or later opportunistic infection is not known. The more research that emerges, the more complex, and common, the bacterium is found to be.
Rather than going into all the science here (and where to start and where to stop....?!) I'll link to the Wikipedia page on the Microbiology of Lyme Disease for anyone who wants to read further. Most of the actual microbiology explains more than I ever could, and links to journal articles. The controversial issues, such as the Lyme vaccine are not discussed fully on that page. However, as a starting point for basic information, it's a good starting point.
I don't want to put too much information in one post, so I'll just leave it at that - the horrifying little buggers that give you Lyme disease, transmitted by the horrid little bugs that suck your blood. Isn't this a wonderful topic.....?!