For every rule, an exception

The current Ebola virus disease (EVD) epidemic has repeatedly confirmed a stark “gradient of infectivity”. On the one hand, those severely ill with EVD represent transmission risks so high that safe care can only be provided in the most well-prepared treatment units. On the other hand, those with few or no symptoms of EVD represent nearly zero transmission risk. The best evidence for this is that there have been over 850 health care worker EVD cases (and almost 500 deaths) since the beginning of this epidemic, yet of the several hundred community contacts of cases in the US, UK and Spain, there hasn’t been a single transmission event outside of an intensive care unit.

Thus the rule I’ve heard, and stated, at various times during the epidemic: “no symptoms, no transmission risk.”

Now the exception: sexual transmission. We’ve long known that filoviruses can be detected in semen for weeks and even months after disease recovery (a 1995 study reported Ebola virus RNA in seminal fluid for up to 101 days, and infectious virus up to 82 days, and in 1968 the sexual transmission of Marburg virus was reported 13 weeks into convalescence). Now a concerning case in Liberia has the WHO recommending indefinite safe sex practice for EVD survivors. From the New York Times article:
"The new guidelines came one day after the death of Liberia’s single confirmed patient with Ebola, Ruth Tugbah. Before her illness, the country had gone three weeks without a new Ebola diagnosis, and hopes had risen that Liberia was nearing the end of a yearlong epidemic that killed more than 4,000 people there. Ms. Tugbah’s only known risk factor was having a boyfriend who was an Ebola survivor. 
Scientists detected the genetic material of Ebola from a semen sample the boyfriend provided to infectious disease investigators, officials from two Ebola response agencies said, speaking on background because they were not authorized to speak publicly."
If further investigation confirms this transmission event, it would indicate that she was infected several months after his recovery from EVD (more than the three months currently suggested as the maximum time virus may be present in semen). Given the sheer number of cases that have occurred in the affected countries, this poorly-understood sexual transmission risk adds an unwelcome twist as the outbreak winds down.


  1. I think it's premature and a bit exotifying to speculate about sexual transmission of Ebola, until it is proven. We've already seen lots of racism in the media's depictions of Ebola in W. Africa... and we know from the history of the HIV epidemic that there was lots of stereotyping about sexuality in Africans/ / African-Americans

  2. Interesting take. Am I exotifying? On the contrary, I believe that finding viable Ebola virus in semen for weeks after recovery requires us to "speculate" about sexual transmission! And indeed we've been speculating about it for a while now, which is why we recommend that those recovering from EVD practice safe sex for 3 months. I'd give that advice to anyone recovering from EVD, regardless of their country of origin, race or ethnicity.

  3. Sorry Dan, that I wasn't clearer. I don't mean that you were exotifying. This is a more general problem with how W. Africa and W. Africans have been represented throughout the outbreak, by the media, and by general observers. I am not an anthropologist but have talked with several who can elucidate this better than I can.

  4. Dan- I am trying to get others more erudite than I am to comment on this issue. Phil Lederer

  5. This concern of sexual transmission of the virus was (briefly) part of the narrative surrounding Kent Brantly after he was cured. But being a doctor/missionary/American, I think there was an assumption he'd comply with protocols. There is also an assumption, I believe, of African promiscuity underlying this current framing of concern--that cured African men in particular will engage in unprotected sex within that 3-month window (as opposed to waiting or wearing a condom). Similar narratives surrounded media/public health/medical depictions of Africans and HIV/AIDS risk. And while there may be some truth to these concerns, there is still the need to be very careful in how we frame these messages, lest they end up further stigmatizing (and alienating) an already vulnerable population.

  6. thanks Prof Simmons :)
    Phil Lederer


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