Following weeks of rising optimism during which no one in Liberia was diagnosed with Ebola, health officials in the West African country announced a new case of the deadly virus Friday.
Liberia had gone 28 days without confirming any fresh cases of Ebola, putting it on track to be officially declared Ebola-free.
Liberia has seen around 9,500 cases of Ebola, including more than 4,200 deaths in the year since the current outbreak began.
The new patient is a 44-year-old woman, a food seller from the Caldwell area near Monrovia, the capital, according to a statement issued by Liberia’s information ministry.
The patient is being treated at a facility run by the aid group Doctors Without Borders, and teams have been sent out to find and monitor people who had contact with the new patient, according to the information ministry statement.
It is not clear how the woman became infected, but the information ministry statement said that, “initial suspicion is that it may be the result of possible sexual intercourse with an Ebola survivor.”
The World Health Organization has cautioned that the semen of male Ebola survivors may be infectious up to three months after their first symptoms appear.
Little research has been done on the subject, but there is evidence that traces of the virus can linger in fluids like semen, urine and breast milk for weeks. There is no formal evidence that Ebola can be transmitted through contact with such fluids, though.
In order for the WHO to declare it Ebola-free, a country must not report any new cases for 42 days after the last confirmed case has tested negative. For Liberia, that deadline would have come in early April.
Beatrice Yardolo, who until Friday was Liberia’s last known Ebola patient, was discharged from a Chinese-run treatment facility on March 5, raising hopes that the nation might soon declare an end to its outbreak.
Although news of the latest infection was unwelcome, it was not unexpected, especially since neighboring Guinea and Sierra Leone are still reporting new cases every week.
“We will have unfortunately some periods in which our hopes are dashed at this stage in the outbreak,” Dr. David Nabarro, the United Nations secretary general’s special envoy on Ebola, told the New York Times.