Ebola Virus Could Persist in Semen of Male Survivors for More Than One Year

Male survivors of Ebola, the infectious disease that plagued western Africa in 2014 through 2015 and caused a media-fueled frenzy here in the United States, can carry viral RNA in their semen for an extended period of time. This increases the risk of male survivors spreading the disease, even after they have recovered from the infection themselves.

New research recently published by a team from the Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and clinicians based in Liberia (1 of the countries affected by the 2014-2015 outbreak), suggests that the virus may persist in semen for up to 565 days. As the authors note in their introductory remarks, “unprotected sexual intercourse was strongly suspected in the transmission of Ebola virus disease from a male survivor… to his female partner” in a previous report, published in 2015.

In this new report, published online on February 15, 2017 by the journal Emerging Infectious Diseases, researchers describe the case of a 48-year-old man with a history of HIV infection (both HIV-1 and HIV-2) who was admitted on August 27, 2014 to an Ebola treatment unit in Monrovia, Liberia with “a 1-week history of fever, chills, and weakness and a 2-day history of vomiting and diarrhea.” Reverse transcription polymerase chain reaction (RT-PCR) revealed that Ebola virus was present in the man’s blood, with a cycle threshold (Ct) of 32.39. He was treated for the virus, and continued to receive antiretroviral therapy for HIV-2 (zidovudine/lamivudine/lopinavir plus ritonavir), while in the facility. He was discharged 11 days later after subsequent RT-PCR was negative.

The patient’s CD4 cell count 4 months prior to his Ebola diagnosis was 459/μL, and it was 529/μL following his recovery from Ebola. In October 2015, the patient was enrolled in Liberia’s Men’s Health Screening Program, which, according to the authors, was established by the country’s Ministry of Health that same year to provide semen testing for Ebola and safe-sex education for disease survivors. Per program protocol, the patient’s semen was tested for Ebola every 4 weeks (via RT-PCR).

The authors report that the patient’s semen tested positive for Ebola (viral structural protein 40 gene and nucleoprotein gene targets with Ct values <40) for 565 days following his discharge from the Ebola treatment unit. His Ct values “plateaued to indeterminate” in samples “up to 758 days” following discharge.

“Although detection of Ebola virus RNA by RT-PCR does not necessarily indicate the presence of infectious virus, a previous study reported Ebola virus infectivity by RT-PCR—positive human semen samples in immunodeficient mice,” the authors write. “The prolonged period during which Ebola virus RNA was detected in this patient adds to evidence that there is heterogeneity in duration of Ebola virus persistence in semen among survivors… Although etiology of this heterogeneity is unclear, possible explanations for this patient include age-associated effects, attenuated clearance caused by dual HIV infection, immunosuppression from etiologies other than HIV, severity of acute illness, or unknown host genetic factors… [C]o-infection with HIV might play a role in persistence of Ebola virus in semen, despite an adequate clinical response to [antiretroviral therapy].”

Based on their findings, the authors recommend that West African semen testing programs for Ebola virus offer HIV screening to male survivors “with persistently detectable Ebola virus in semen.” They add that, “This case-patient had a favorable outcome… despite being HIV positive, which emphasizes the need for continuing treatment for HIV infection in the setting of a large-scale Ebola outbreak.” HIV treatment was interrupted in many West African nations during the Ebola outbreak, the authors report.

This new information comes on the heels of another study that recently provided evidence showing more than 60% of secondary cases in the 2014 to 2015 Ebola epidemic descended from a small number (about 3%) of superspreaders.

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.