By Drs. David Niesel and Norbert Herzog, Medical Discovery News
When you get sick, how do you know when it's safe to come into contact with other people without spreading the infection? For many infections such as influenza, you get sick one to four days after being exposed, and you can spread the virus for an additional five to seven days after becoming sick. Now consider the importance of that timeline when it comes to a deadly virus like Ebola. The 2015 Ebola outbreak in West Africa has been declared over, but we may need to rethink that conclusion.
Ebola causes an acute illness that has a high mortality rate. People become infected, many die (up to 80 percent), but some recover. It was thought that once you survived the infection, you could not infect other people and you were immune against the virus in the future. However, we have learned that once you have become infected with the Ebola virus, you are not free of the virus when your symptoms disappear. The virus is not necessarily gone from your body and can re-emerge.
Lately, a new twist in this news has significant public health implications. A Liberian woman contracted Ebola from a male sex partner, who was an Ebola survivor. The couple had sex nine months after the male was first infected with Ebola and more than 150 days after he was determined to be free of infection. Based on this clearance, the couple had unprotected sex at a point beyond the three-month waiting period currently recommended by health authorities. Molecular analysis and sequencing of the virus showed that the virus did most likely come from her male partner and not from another source. Ironically, she became infected just 30 days after the West African nation of Liberia was declared Ebola-free. Unfortunately, the woman did not survive the infection. The recommended waiting period for unprotected sex has now been extended to six months after recovery.
Recent studies found males who recovered from an Ebola infection still had the virus in their semen. No reactivation of this infection from this source have been reported yet. In additional studies, semen samples from almost 100 Ebola survivors were tested for the virus. Half the men carried the virus for up to six months and a quarter carried it for up to nine months. If there is good news, it appears that sexual transmission of Ebola is rare. Fewer than 20 cases of sexual transmission were observed from the 17,000 male survivors. Still, the U.S. Centers for Disease Control has recommended the testing of male survivors until two consecutive tests of semen are negative and more is understood about sexual transmission. Safe sex practices should be used during this period.
Research on Ebola has intensified since the outbreak. Now there are promising new vaccines in field and laboratory testing, offering real hope that epidemics like this one will not happen again.
Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at www.medicaldiscoverynews.com.