Thanks for your detailed reply
@LHCTom. However I do think there are some flaws in your argument.
...its how likley and what is the real risk?
Yes this is what we are trying to establish.
Evolution is very good at optimizing each step in the path of a succesfull life cycle of a microbe like Treponema pallidum or Borrelia. Syphillis has adapetd to direct host to host sexual transmission while Borrelia has adapted to vector based transmision.
Due to the short life cycle of bacteria they can easily evolve over a few decades. Borrelia has had at least 30 years to adapt to sexual transmission. If it was ever possible to transmit even once sexually it has got a whole lot better at it by now.
Its very naive to think that just because Treponema pallidum and Borrelia are spirochetes, that they both can equally traverse the others optimized path. That is just a general concept that impacts probability.
The reason this makes it so much more likely is because being spirochetes they easily get into all parts of the body which other infections can't. I think this fact highly impacts probability.
So is Lyme sexual transmission possible? The answer is probably yes but the probability is probably very low. Just because airplanes crash and you can die in an auto accident, you probably fly and drive all the time because you know the odds are very good but not 100%.
No, if every time a plane crashed, the next plane taking off acquired the same fault thus was more likely to crash, planes would soon be crashing all the time.
This study only looked at whether Lyme spirochetes were present in the fluids involved in sexual transmision...
No it didn't. It also found that 100% of the three partners having unprotected sex had identical strains. That is quite a coincidence since there are about 300 strains worldwide if it's not sexually transmitted. Dr Marty Ross considers it unlikely that even one couple would have the same strain.
The female vaginal fluids are very hostile to microbes...
As this study (and others) found Borrelia in vaginal fluids it is obviously not very affected by it.
Your innate immune system is the primary rapid defense that prevents microbes from finding their way through the tissue and into the blood system...The most difficult half of the transmission path is its entry through the sexual organ tissues.
Borrelia is a master of immune system evasion. It is also master of getting into all areas of the body tendons, brain, joints...everywhere. I don't see why it would find it a problem getting through sexual organ tissue.
Direct access to the blood system via injuries will impact whether the innate immune system is able to stop the transmision.
Treponema pallidum does not require direct access to the blood system or it could not be transmitted to someone who doesn't have sores. It simply helps it. It is a spirochete so can burrow through tissue, so can Borrelia.
The number of microbes will also impact the probability...The number of spirochetes passing the vaginal fluid will impact the probability. There is a big difference between 5 and 50,000 and 5 million.
This is a non issue for Borrelia. If you can catch Lyme from a mosquito bite it is clear that this particular bacteria does not require large numbers to effectively transmit.
The innate immune system cannot be avoided by hiding in a cell.
Intracellular replication can evade the innate immune system. An example of this is tuberculosis. Borrelia can be encapsulated in tissue such as lymphocytic cell walls hiding it from the immune system. Biofilms can protect form the innate immune system. So it can be avoided.
There probably have been cases where sexual transmission ocurred
If it occurred once Borrelia have likely adapted by now to this method of transmission.
If you just understand that both men and women's sexual organs are typically exposed to many pathogens and the innate immune system prevents systemic infection...
The difference is that we are talking about spirochetes which are very different from most pathogens due to their ability to easily go through tissues.
In one of the press releases on this study, it was suggested the jump in the number of cases of Lyme was a result of sexual transmission is just silly. If there are 200,000 cases each year, then the number due to sexual transmission is probably <10.
This is silly based on what? Your opinion?
Identifying an actual strain involves a multi-locus PCR and sequencing as many as 8 genes for reasonable certainty. The PyrG gene is identical across almost 10 known strains of Bb. If people live in a geographical area then many of the strains in the area will share many identical genes. So just to be sure 2 people have the same strain requires sequencing many genes.
From the study:
PCR isolates of genital cultures from three couples having unprotected sex (Patients 6-7, 10-11 and 12-13) were subjected to Sanger sequencing and BLAST analysis. Patients 6, 7, 10, 11 and 13 had sequencing done at Australian Biologics, while Patient 12 had sequencing done at University of New Haven. Sequencing revealed that the first and third couples had
Borrelia strains that matched Bb
sensu stricto strain B-31 (
Table 6). In contrast, the second couple had PCR sequences that matched
B. hermsii strain YOR. Thus the
Borrelia strain shared by this couple differed significantly from the strains identified in the other couples.
That sounds like fairly comprehensive analysis to me.
Even if a study found many couples with identical strains, its like showing people die in airplane crashes. Yes they do. But not many as a percentage of people who fly.
No it's not. You are assuming that many couples with Lyme have different strains and that the ones with the same strains have been "cherry picked"...what has been shown from this study is that three out of three couples have the same strain making the probability quite high that sexual transmission was caused in these cases. They have not been cherry picked.
Finally Dr Ross states:
The Lyme infection, borrelia, can be sexually transmitted. However we do not know the actual rate or chance of transmission. There is limited science around this topic, but here it is.
- Studies do show borellia in vaginal fluid and male ejaculate of those who have positive testing with Lyme disease (1, 2).
- In one recent study, one couple tested had identical strains of borrelia (1). The likelihood that they both contracted the same strain separate from each other (from two different tick bites) is possible but quite small.
- Lyme is a spirochete like syphilis which is well know to be sexually transmitted.
- Most Lyme Literate Medical Doctors (LLMD) treat married and other committed partners who both have Lyme disease.
- The actual sexual transmission rate is not known.
This information predates the above study which gives far stronger evidence.
So...we have a bacterium which is able to get through any tissue, survive in sexual fluid no problem and is a master at immune evasion. We have LLMD who treat many partners and was found in three out of three couples to have identical strains. In my own limited experience about 1/4 of Lyme patients I have met personally have partners who also have it.
Based on all this I would say the probability of sexual transmission is
extremely likely.
JBB