— EDIT —
There is an excellent and very thorough new analysis of this issue, in two parts, at
While it is a blog post, it is more recent than mine and at least as thorough if not more. I encourage those interested in the topic to read it.
— END EDIT —
I’ve been wondering on and off for some time whether I need to worry about sexual transmission of Lyme disease. Now I’ll be honest, although I love my spouse very much, it hasn’t been that much of an issue in the last year or two. But I’m starting to feel a little better, and the last thing I want to do is create a husband who can’t get off the couch just when I’m able to enjoy him.
Humor aside, I decided to do a literature review for myself on the issue. Not being an expert in this field, I am trying very hard to avoid much interpretation of these results, but here’s a raw dump of what I found (note: Bb, and Borrelia Burgdorferi both refer to the causative agent of Lyme disease, the spirochete Borrelia Burgdorferi and (in some cases) related strains that also cause Lyme disease).
- Some animal studies have included tests of sexual transmission. For example in a 1991 study Moody and Barthold infected rats and exposed uninfected rats to them . One group just had contact, another group was pregnant, a third was tested for venereal transmission. In no case did infection occur. A similar 1999 study by Woodrum & Oliver showed no transmission. Because I can only access the abstracts, one thing that’s unclear is how long these studies went on for. For example, if sexual transmission is possible, it might be so infrequent that many many animals must be tested or very long periods of time must pass before sexual transmission would be found. Jenna’s Lyme Blog mentions some studies I was unable to track down that may have demonstrated sexual transmission.
- As far as I could find, this has not been studied in human settings. That means that there are no studies proving sexual transmission, but also none disproving it.
- There are anecdotal reports that suggest sexual transmission may be possible. One example is the many reports of lyme patients whose partners are also infected. However, I was unable to find any research quantifying how often this happens or explaining whether it is simply similar exposure to tick-infested environments that cause this.
- Another example is the article by Gasser et al. . However, this is a letter to the editor and not a peer reviewed article, which makes it less trustworthy as a source of evidence. Also, the evidence for sexual transmission is weak (“no memory of a primary infection” on the part of the husband).
- One article hypothesizes that sexual transmission may occur (it was published in a journal called “Medical Hypotheses”). In this article , Harvey & Salvato state “Inferential data, however, suggest the possibility of human sexual transfer. The data come from sound veterinary studies, [and] the finding of Bb in human semen and breast milk.” The authors also mention the similarity of Bb to syphilis. Unfortunately, their choice of references seems odd – I could only access abstracts, but the first appears to show congenital transmission and to question why cattle in a non-endemic area would have infection, it is not a controlled test of sexual transmission based on the abstract. The second, similarly, is titled “Evidence for in-utero transmission …” and appears to focus exclusively on that. The third is about dogs and congenital lyme. I’m not really sure why any of them is referenced as evidence for venereal (sexual) transmission.
- It appears that Bb can be present in human semen up to 40% of the time . However the referenced article was submitted as an abstract to a conference and (as far as I can tell with a quick google search) never published in a journal. Why not? Also, the presence of Bb in semen does not necessarily indicate that it can infect someone.
To summarize, I was unable to find any peer-reviewed evidence of sexual transmission in human or animal studies. However, I did not find a large number of studies that showed a lack of sexual transmission, nor could I track down enough details to judge how thoroughly they tested the hypothesis. Also, I did find some articles that claimed that sexual transmission could happen, but was not able to find clear evidence backing them up, and most were not published in peer-reviewed journals. I was disappointed to see that the one review article on the subject () did not have solid references for its claim that sexual transmission was possible. Presumably they had the resources to track this down more carefully than I do.
To be honest, I am frustrated by these results and wish that I had more clarity. My LLMD has assured me that there’s nothing to worry about and the studies I found certainly seem to agree. My gut says be careful — Lyme is not something to wish on anyone else, much less give to them. It doesn’t help that so many articles about other aspects of Lyme disease stand in stark disagreement to each other — I have been conditioned to question every research result I find at this point.
I should note that there appears to be far more research on and evidence for the possibility of congenital lyme disease. “Anecdotal” stories in humans are also much easier to take as proof in this case — if a newborn infant tests positive for Bb, it’s hard to argue that this was acquired through a tick bite! A natural question is whether blood transfusions can be a source of infection. I have not researched either congenital transmission of Lyme disease or issues with blood transfusion myself, but you may want to think about whether to give blood if you are infected. Another limitation of this review is that I did not look for research on the possibility of sexual transmission among Lyme co-infections.
 Moody, K. D. & Barthold, S. W. (1991) Relative Infectivity of Borriela Burgdorferi in Lewis Rats by Various Routes of Inoculation. Tropical Medicine and Hygiene, 44(2):135-139. Abstract
 Woodrum, J. E. & Oliver, J. H. (1999) Investigation of venereal, transplacental, and contact transmission of the lyme disease spirochete, Borrelia Burgdorferi, in syrian hamsters. J. Parasitol. 85(3):426-430.
 Gasser, R., Dusleag, J., Reisinger, E., Stauber, R., Grisold, M., Pongratz, S., Furian, C., Feigl, B., & Klein, W. (1994) A most unusual case of a whole family suffering from late lyme borreliosis over 20 years. Letter to the Editor, Angiology 45(1):85-??. First page
 Harvey, W. T. & Salvato, P. (2003) ‘Lyme disease': ancient engine of an unrecognized borreliosis pandemic?. Medical Hypotheses, 60(5):742-59.
 Bach, G. (2001) Recovery of lyme spirochetes by PCR in semen samples of previously diagnosed lyme disease patients, Presented at the International Scientific Conference on Lyme Disease