(Bloomberg) – Lab tests confirm that the Ebola virus has killed a patient in Sierra Leone.
Public health authorities believe the virus has also caused four other deaths in that country, the World Health Organization said in a statement.
Sierra Leone has become the third country to report Ebola deaths since March.
Authorities have recorded 258 Ebola infections in Africa since March and 174 Ebola-related deaths.
The outbreak seemed to be waning, but now the affected area appears to be expanding.
Inside Guinea, officials have reported eight Ebola cases and three deaths in the Telimele district. The district has not previously reported any cases of Ebola, WHO officials said.
The deaths in Sierra Leone occurred in a region across from a part of Guinea that’s been hard hit by the Ebola outbreak.
The virus, first identified in 1976 near the Ebola River in what is now the Democratic Republic of the Congo, is transmitted to people through the blood and other secretions of wild animals such as chimpanzees, gorillas, bats and porcupines, according to the WHO. Humans transmit the virus to each other through contact with blood and other body fluids. Previous outbreaks have killed as much as 90 percent of those infected. There are no approved drugs or vaccines to treat or prevent Ebola.
Ebola is one in a handful of diseases that are so deadly and so contagious that they pose a risk to national security, according to the U.S. Centers for Disease Control and Prevention. The agency lists the virus as a Category A bioterrorism agent, alongside anthrax and smallpox.
The WHO said it doesn’t recommend any travel or trade restrictions with Sierra Leone.