An Ebola survivor from Liberia who was exposed in September 2014 may have spread the virus to a woman in March, according to a CDC report published in May.
An investigation found that the woman (patient A) stated she had unprotected vaginal intercourse with the survivor (known as survivor A).
Published reports from recent outbreaks have shown Ebola survivors can continue to harbor the virus in immunologically privileged sites after convalescence. “Based on information gathered in this investigation, CDC now recommends that contact with semen from male Ebola survivors be avoided until more information regarding the duration and infectiousness of viral shedding in body fluids is known,” researchers stated in the report.
In March, the infected woman developed headache, weakness, joint pain and nausea and was triaged as a suspected Ebola patient to a nearby transit center. Ebola was confirmed by reverse transcription-polymerase chain reaction.
Patient A reported unprotected vaginal intercourse with survivor A, a 46-year-old man who experienced Ebola symptoms in September. His blood samples were negative at that time.
“Ebola virus RNA in survivor A’s semen in March 2015 does not prove the presence of infectious virus,” researchers stated. “However, the absence of patient A’s genetic signature in sequenced RNA from three patients in Liberia’s last known cluster of epidemiologically-linked cases makes it unlikely that patient A was infected from unrecognized, ongoing community transmission. Culture of survivor A’s semen specimen for Ebola virus is planned to determine whether viable virus was present.”
Survivor A had an older brother who had a confirmed case of Ebola on Sept. 5, 2014. In addition, a younger brother and daughter were admitted to an Ebola treatment unit later that month. Both died and no laboratory results are available for those patients. In October, survivor A’s son died of Ebola.
A blood specimen collected from survivor A on March 23 was negative for Ebola virus by RT-PCR, however a semen specimen tested positive by RT-PCR and a partial genome sequence obtained so far closely matches the sequence from patient A, researchers stated.
In addition to patient A, survivor A reported unprotected vaginal intercourse with another woman, aged 45, in February and March of 2015. A blood specimen taken from the second woman was negative for Ebola.
Researchers concluded “the timing of intercourse between survivor A and patient A, the subsequent illness in patient A, the presence of viral RNA in survivor A’s semen, matching genetic sequences (where coverage has been obtained) in isolates from survivor A and patient A, and the lack of other known exposures suggest possible sexual transmission.”
They stressed the importance of preventative measures, such as condom use, in Ebola-affected countries.
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