This week, as the World Health Organization (WHO) declared the Ebola outbreak in the Democratic Republic of the Congo (DRC) over, a new study reveals a concerning finding: female survivors of Ebola Virus Disease (EVD) may transmit the virus. Previously, only transmission from a male survivor had been suggested. This new data highlights the need for DRC (and any other country that has dealt with an Ebola outbreak) to maintain vigilant disease surveillance even after the outbreak is over.

Since the 2014 West Africa Ebola epidemic, there have been two other Ebola outbreaks, both in the DRC. Although these outbreaks have been devastating in terms of morbidity and mortality, data obtained from these outbreaks have helped improve the understanding of disease transmission and pathology. A key discovery made during the outbreak in West Africa in 2015 was of the possibility of male-to-female sexual transmission from Ebola survivors. Although the WHO maintains that sexual transmission of Ebola has not been proven, it does acknowledge that the virus can remain in the semen of Ebola survivors for an extended period of time.

Now, the results of this new study reaffirm concerns about the long-term persistence of Ebola virus among survivors and also suggests that female EVD survivors may, too, be capable of transmitting the disease. The study authors investigated an EVD cluster that occurred in a family in Liberia in November 2015--just a few months after Liberia had been declared free of Ebola virus transmission in September. The aim of the study was to determine how the deceased index case, a 15 year old male, was exposed to EVD. Samples from the boy’s father and younger brother would also later be confirmed to have Ebola virus RNA.

Several transmission scenarios were assessed, including possible travel or funeral exposures, exposure through blood transfusions, and sexual contact with known Ebola virus survivors. When these were determined to be unlikely, the investigation turned to a potential exposure to a persistently infected individual. It was determined that the boys’ mother had suffered from Ebola-like symptoms in July 2014, although she did not seek care and was thus not definitively diagnosed. The mother later gave birth in October 2015, and may have experienced a recrudescence of EVD. Genotypic sequencing of cases involved in this cluster, along with testing of samples from cases that the mother was thought to have acquired EVD from back in 2014, demonstrated that this was not caused by the “independent introduction for an unknown non-human reservoir but was a continuation of the west African Ebola virus disease outbreak that began in 2013.” Given this information, it was determined that the mother was the likely source of infection, and may have experienced a recrudescence of Ebola due to pregnancy-induced immunosuppression.

This study adds to the growing body of evidence around long-term persistence of the virus in survivors and raises concerns about the possibility of future transmission. After the 2014 epidemic, Liberia launched a Men’s Health Screening Program, meant to follow the WHO’s recommendations for semen testing for male EVD survivors. In light of these new findings, enhanced surveillance of female survivors may also be necessary.

This study also raises concerns for how Ebola survivors will be treated within their communities. Individual survivors of Ebola have faced stigmatization in the wake of each outbreak because they were perceived to still have the capacity to infect others. Data supporting long-term persistence of the virus among survivors may exacerbate stigmatization of survivors. Of particular concern is the new finding that women may be capable of transmitting the virus after they recover from their illness. The United Nations Population Fund has cautioned that women and girls, who generally have less access to jobs and education than men, are especially vulnerable to stigma and may face higher “barriers to resuming their normal lives”.

Above all, what this study confirms is a need for continued Ebola surveillance even after outbreaks are contained. Outbreak Observatory has discussed Ebola outbreaks many, many times.  After the West Africa Ebola epidemic, there was a global call to establish robust health systems with the capacity to weather day-to-day needs, as well as to respond to emergencies like Ebola. As more is understood about the nature of EVD and its transmission in survivors, we must continue to pursue the establishment of strong health systems which can keep up with all aspects of outbreak response, even those that happen once the outbreak is over. The need for a health system which can be vigilant in the wake of yet another EVD outbreak is paramount.

Photo courtesy of CDC/Cynthia Goldsmith

Outbreak Observatory aims to collect information on challenges and solutions associated with outbreak response and share it broadly to allow others to learn from these experiences in order to improve global outbreak response capabilities.