Scientists discovered that the woman had taken care of her brother in July 2014. He died after suffering from Ebola-like symptoms but before being tested for this condition. The woman later experienced a similar illness, but never sought care.
Several weeks after the birth of a baby in September 2015, the woman developed problems such as tiredness and respiratory problems. Doctors say that because pregnancy lowers the body's immune system, it may have enabled the recurrence of the Ebola virus.
"The suspicious disease she had after birth could have been a reactivation of Ebola. We have no confirmatory tests," Dr. Emily Kainne Dokubo, who led the Ebola response in Liberia to the US Centers for Disease Control and Prevention and was the lead author of the study.
Dokubo said it was possible that the woman infected her husband and two older sons with Ebola if they took care of her ̵
"There is no complete evidence to reconstruct what happened, but this is the most likely scenario," said Lorenzo Subissi, epidemiologist at Sciensano, a Belgian research institute that was not part of the study.
Dokubo said such cases of Ebola recurrence are exceptional, with only two reported instances: a Scottish nurse who caused meningitis caused by Ebola in her brain and an American doctor who had developed lingering virus in his eye. In these two cases, the virus did not spread further.
"We do not want to have a sense of complacency with people who think just because the outbreak is over, there's nothing left to do," Dokubo said. "There is a risk of viral persistence, and people should be taken care of right away so that we can immediately detect suspicious cases and stop a major outbreak."