DAKAR, Senegal — Samples taken from the 17-year-old boy who died from Ebola in Liberia nearly two weeks ago show the virus is genetically similar to viruses that infected many people in the same area more than six months ago, the World Health Organization said Friday.
That finding by genetic sequencing suggests it is unlikely the virus was caught from travel to infected areas of Guinea or Sierra Leone, the group said. "It also makes it unlikely that this has been caused by a new emergence from a natural reservoir, such as a bat or other animal," it said.
Five new cases have been confirmed in the town of Nedowein, including the teen who died June 28. The four people infected with Ebola are among 149 identified contacts, the WHO said.
Blood tests are being done on all of those contacts to see if "there are people who had the virus in their bodies without knowing it," said Dr. Margaret Harris, a spokeswoman for WHO.
More than 4,800 Liberians died of Ebola before the country was declared free of transmissions in May.
"There are a considerable number of survivors. And we also know that it persists in certain bodily fluids, and that it can subsist for at least six months," Dr. Harris said, adding that the transmission could have been sexual. "It's a possibility and it's only a possibility."
The Ebola virus spreads through direct contact with an Ebola patient's blood or other body fluids like urine, saliva, semen and sweat. Once patients recover, health officials say they aren't contagious except there's a chance it could still be in semen.
The Ebola outbreak has killed more than 11,200 people, mostly in West Africa. The presidents of Liberia, Guinea and Sierra Leone are appealing at a U.N. conference for $3.2 billion to help their countries recover.
This story was corrected to show that the teen died nearly two weeks ago.