Use of saliva as a lubricant in anal sexual practices among homosexual men.

In contrast to other sexually active adults, men who have sex with men (MSM) are at greater risk for infection with a variety of pathogens including cytomegalovirus (CMV),1 hepatitis B virus (HBV),2 and the more recently discovered Kaposi sarcoma-associated herpesvirus (KSHV).3,4 Why these pathogens are disproportionately represented among MSM is not well understood. Although a simply greater number of partners among some MSM could be responsible, the other common link between these 3 pathogens is their presence in saliva.5–12 For example, for one of the organisms, KSHV, saliva is the body fluid that most commonly harbors the virus.5,6 HBV, although most commonly found in blood, is also commonly shed in saliva; between 15%–67% of individuals with chronic infection have detectable HBV DNA in saliva.11–14 In the largest studies of CMV, HIV-infected men, in particular, commonly harbor CMV in their saliva with 50%–60% prevalence.7,9 Directly investigating the role of saliva in spreading pathogens is difficult, but for at least HBVand KSHV, there is evidence for saliva as a conduit in transmission.15–17 Hence, it is surprising that limiting exposure to saliva as a means for avoiding infection has received little attention. For example, for CMV, guidelines for the prevention of opportunistic infections among HIV-infected persons note the presence of CMV in saliva, but only recommend as an intervention the use of condoms.18 For HBV, guidelines make no mention of the role of saliva.18 It is only for KSHV where caution regarding a specific saliva-exchanging act, kissing, is given.18 In part, the lack of attention to saliva may stem from the belief that exposure to saliva, via kissing, is ubiquitous and cannot be avoided. However, kissing is common among both heterosexual adults and MSM, yet CMV, HBV, and KSHV all are less common among the heterosexual population.1–4,19 This suggests that kissing alone is not the sole means of spreading these organisms. Despite this, very little is known about what other avoidable practices might spread saliva from person to person. One relatively unrecognized mode in which saliva may be exchanged among MSM is via the use of saliva for lubrication in anal-based sexual activities, a practice acknowledged in condom failure research,20,21 anecdotally in internet-based forums,22 and more recently as underemphasized components of broad surveys of sexual practices among MSM.23,24 To systematically address the prevalence and determinants of the use of saliva as a lubricant in anal sexual acts, we examined a population-based sample of MSM.