Quackwatch has long maintained that ‘People are “dead end” hosts and do not spread Lyme infections to others’ but if viable bacteria are found in semen and other sexual secretions perhaps a reassessment of Lyme disease as an STD is necessary.
Lyme Disease – An STD?
The US Centers for Disease Control (CDC) maintains that Lyme disease is not transmitted through sexual contact and there has not, until now, been any real evidence to suggest otherwise. Just as the CDC has recently updated their estimates of actual cases of Lyme disease in the US from around 30,000 cases a year to some 300,000, it may be that some in the Lyme disease advocacy community will call on them to rewrite diagnostic guidelines to recommend that fluid bonded partners of those diagnosed with Lyme disease are also tested and able to access early treatment and/or adequately protect themselves against infection. After all, Lyme disease bacteria are spirochaetal, just like the bacteria that cause syphilis, a well-known sexually transmitted disease (STD).
Identical Bacterial Strains in Fluid-Bonded Couple
The lead author of this latest study, Marianne Middelveen, notes that their findings may offer an explanation for the high incidence and prevalence of Lyme disease, with the number of new cases rising faster than might be expected if transmission by tick bite were the only factor in new cases.
To assess the possibility of sexual transmission of Lyme disease the researchers tested vaginal secretions and semen from control subjects without signs of Lyme disease, subjects with positive tests for Lyme disease, and married fluid-bonded heterosexual couples who had also tested positive for Lyme disease. Controls showed no evidence of the spirochaetes in the secretions. Those women who had tested positive for Lyme disease were found to have the bacteria present in their vaginal secretions and half of the men with Lyme disease tested positive for Lyme disease bacteria in their semen.
Is the Real Danger of Lyme in the Bedroom?
Interestingly, one couple tested positive for identical strains in vaginal secretions and semen, suggesting sexual transmission. It is, of course, entirely possible that the couples were exposed to identical strains of the bacteria through tick bites. Clearly, however, these results do not confirm sexual transmission of Lyme disease in any couple who were fluid-bonded, as the study only tested secretions. In order to determine transmission the couples would have had to be tested to verify that one had Lyme disease and one didn’t and then be tested again after having had unprotected sex without any other means of transmission. Clearly this throws up some interesting ethical questions around research and exposure, but the exact same studies have been done using animals and no evidence was found that Lyme disease is an STD.
The researchers in this latest study are interested, however, in why only half of the men had the bacteria in their semen but all the women tested positive.
A dermatololgist involved with the study noted that while there’s always some risk of getting Lyme disease from tick bites “there may be a bigger risk of getting Lyme disease in the bedroom” – a claim which seems somewhat hyperbolic and sensationalistic.
Lyme disease is now estimated to be twice as common as breast cancer and six times more common than HIV/AIDS, but there remains no definite proof that the presence of these bacteria in semen or in vaginal secretions actually leads to Lyme disease being a sexually transmitted disease. In fact, the evidence from animal studies suggests that Lyme disease is not transmitted through sexual activity.
Reference: The Journal of Investigative Medicine 2014;62:280-281.
Presented at the Western Regional Meeting of the American Federation for Medical Research, Carmel, CA, January 25, 2014.