Liberia is fighting against a return of the Ebola virus as five people have recently been diagnosed with the disease.
The country's Ministry of Health confirmed that another 149 people remain in quarantine after the virus was detected in the body of a teenager outside Monrovia on June 29.
Genetic sequencing of virus samples taken from the body revealed that it is genetically similar to the strain of Ebola that devastated Liberia last year during the height of the outbreak, according to the World Health Organization.
As a result, the WHO said it's likely the virus was not "imported from infected areas of Guinea or Sierra Leone." It's also unlikely it was contracted from an animal infected with the disease.
Dr. Margaret Harris, a spokeswoman for WHO, said further tests are being done on people in the area to see if they had the virus in their body and didn’t know it.
"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 told the Associated Press.
She also said there’s a possibility that the transmission could have been sexual.
The Ebola outbreak was declared over by the WHO on May 9, but Liberia was under a 90 day “heightened surveillance” period when the new cases were discovered. Ebola is spread through bodily fluids between people in close contact. After patients recover they are no longer contagious, but virus particles have been found in semen months after an infection.
The Ebola outbreak that started last year in West Africa killed more than 11,200 people.
The Associated Press contributed to this report.