Ebola is again in news. Royal Free Hospital in London revealed on Wednesday that a nurse from Scotland who had recovered from deadly Ebola disease months ago is back in hospital, and this time, she is critically ill.

Scientists studying the disease knew that the virus can remain in a patient’s certain tissues of the body for some months. As per Wednesday’s report of The New England Journal of Medicine, traces of Ebola virus have been found in some men’s semen a few months after they fell ill. Another report of the journal reported that a survivor of Ebola in Liberia transmitted the disease to sexual partner about six months after the disease’s symptoms.

The new Ebola case of the Scottish nurse, Pauline Cafferkey, showed that there are several things that are still unknown about the virus and its effects on human body for long time. Health experts are trying to understand why the nurse contracted the disease many months after developing the disease in Sierra Leone, where Cafferkey had gone as a volunteer.

Dr. Daniel Bausch, a technical consultant on Ebola with the World Health Organization, said the Ebola case of Scottish nurse is an emerging story.

Dr. Bruce Aylward, Head of the World Health Organization’s Ebola effort, said, “It’s reminded people that the consequences go on so much longer for survivors. It’s really spurred concern we make sure the needs of these people aren’t lost”.

Recently, two new cases have been reported in Guinea, which showed that the outbreak, which killed over 11,000 people, has still not ended.