The Centers for Disease Prevention and Control (CDC) has spent the last decade or two trying to convince people to wear condoms during sexual intercourse in order to reduce the risk of HIV transmission. Prior to that, it and other public health authorities had spent many decades trying to get people to wear condoms during sexual intercourse to reduce the risk of acquiring gonorrhea or syphilis. And well before that, for at least 400 years, the condom was a popular form of birth control worldwide.
Now, the CDC finally has something to scare people into putting one on, a motivation so powerful that just about everyone reading this article will think twice about going latex-free at the next close encounter: Ebola.
Yes, the Ebola virus is potentially a sexually transmitted disease. Some have suggested that sexual transmission may account for some of the cases in the current completely uncontrolled outbreak engulfing West Africa. The risk is great enough that most experts recommend no unprotected sexual intercourse for three months after recovery.
The evidence is simple and quite compelling. It has been known for a long time, from other outbreaks, that a man who recovers from Ebola—in the current outbreak, about 45 percent survive—has detectable Ebola virus DNA in his semen for up to seven weeks. In addition, among infected women, viral DNA has been found in vaginal secretions for weeks after recovery. No one is certain that the viral DNA is actually living, transmissible virus—but any time a rapidly dividing virus is detectable for that long it is, in my opinion, certain that the virus is in fact alive and ready to kick.
A man who recovers from Ebola has detectable Ebola virus DNA in his semen for up to seven weeks.
Which brings up the next question: What is the transmission rate of this virus during a single episode of sexual intercourse? No one knows yet, but countless studies have been performed in HIV to determine the rate of transmission from a single sexual encounter between one infected and one non-infected person. The rate varies according to how high the amount of virus in the bloodstream is, as well as the pairing and the type of intercourse, but in general, the odds are about 1 in 200 to 2,000 for vaginal intercourse and 1 in 100 for anal intercourse. It is likely that the Ebola transmission rate is comparable, though until we know more about the most important variable—the amount of virus in semen and vaginal secretions, as well as blood—this is entirely speculative.
These facts cast a new nightmarish tint to an already overwhelming public health calamity. Till now, the epidemic probably has been perpetuated by poor health care infrastructure, as well as the physical and emotional toll among those caring for patients. But consider what the next wave might be: About 1,500 people in the current outbreak are known to have survived the infection; undoubtedly there are thousands more who went undiagnosed but pulled through. Many of the survivors right now have detectable amounts of Ebola virus DNA in their semen or vaginal secretions—and many of them, presumably, are having sex.
In other words, the global catastrophe ahead may come not from Syria or Ukraine or North Korea, but from the omnipresent mammalian urge to copulate.
In other words, the global catastrophe ahead may come not from Syria or Ukraine or North Korea, but from the omnipresent mammalian urge to copulate. If Ebola indeed enters the public sphere as a sexually transmitted disease—not a disease transmitted only by caring for the dying or burying the dead—the possibilities surely are frightening.
But this is where the CDC needs to step it up. Its messages thus far have been health care worker-directed only—one must read the fine print to learn about the potential for sexual transmission. And unlike so many other public health messages, talking up the risk of sexual transmission of Ebola is likely to work. The fear of acquiring HIV has been only partially successful in encouraging condom use—somehow the disease, though vivid, is at the same time quite abstract. The latency period from infection to clinical symptoms is almost a decade, making today’s actions apparently inconsequential.
In contrast, word that Ebola might be sexually transmitted would likely bounce very differently. Here, the time from exposure to illness is not years but days—and the death a rapid and pitiful one. An informed consumer, hopefully, would hear the message and do something about it.
Don’t think so? Consider this: Rates of gonorrhea, a similar painful (though not fatal) infection that develops within days of sexual contact actually rose after the introduction of penicillin as people adjusted their behavior to the perceived reduction in the risk of illness. Prior to the remedy, couples had protected themselves with condoms and what-have-you. But once there was a cure, the condoms flew off and unexpected pregnancies, gonorrhea, and all sorts of mayhem ensued. Sociologists refer to this sort of in-midair rapid switch as risk compensation.
Risk in the other direction can rapidly be understood by the public and behaviors adjusted on the fly—because fear works. And if the approach seems heavy-handed, well, as their anti-smoking ads attest, the CDC is not afraid to frighten the crap out of people in order to get them to behave differently. So why not take the ongoing tragedy of Ebola and turn it to some public health benefit—by scaring everyone into using condoms.