People dry protective gear in a medical camp in the town of Gueckedou, in southern Guinea, in an image provided by Doctors Without Borders. (AFP/Getty images)

While the weekend's revelations about the plague from teeth of 14th-century skeletons were riveting the Internet, medical workers and health authorities in West Africa were working to stop a more modern threat: the spread of the Ebola virus. The current outbreak has already killed 78 people, according to the Associated Press.

That doesn't compare with the estimated 75 million killed by the Black Death, but this is the 17th Ebola outbreak in which 10 or more people have died, according to data from the World Health Organization. The Zaire strain, identified as the one in this outbreak, kills more than 90 percent of the patients, according to a Doctors Without Borders epidemiologist.

(Why is Ebola so deadly? How does it spread? Here's more on the virus.)

And this Ebola outbreak, which began in Guinea, is spreading: Liberia has confirmed two cases, including one death, the AP says. Senegal has closed its land border with Guinea.

Doctors Without Borders is expressing concern, saying this outbreak of the hemorrhagic fever is less geographically contained than previous instances, making it harder to control. Health workers are trying to identify those who have been in contact with people who have been diagnosed with Ebola and set up ways to isolate patients in the disparate places the virus has been found.

“We are facing an epidemic of a magnitude never before seen in terms of the distribution of cases in the country,” said Mariano Lugli, coordinator of the group's project in Conakry, Guinea's capital.

Ebola is spread from person to person through direct contact with bodily fluids of infected people and can spread even from the deceased to the living, if people embrace the body during a funeral ceremony. Ebola usually starts with a fever, weakness and a sore throat, the WHO says. That's followed by vomiting, diarrhea, rash and sometimes both internal and external bleeding. There's no vaccine or treatment. Ebola spreads quickly, but it also kills quickly, which can impede its ability to spread.

Quick reaction by health workers to identify and isolate deadly viruses can help prevent them from killing half of a nation's population -- as happened with the Black Death in Britain -- but epidemics are not a thing of the past.

Senegal superstar Youssou N'Dour canceled a concert scheduled for the weekend in Conakry to avoid bringing a crowd together.

From the Morning Mix: Everything you thought you knew about the Black Death is wrong, the bones say