News of an Ebola outbreak in Western Africa has been simmering beneath the rest of the world going to hell this summer, but the news, and the disease itself, may have boiled over this weekend. The outbreak has now touched four African nations, killed one doctor tending the sick, and two infected Americans are getting treatment in Liberia—one doctor and one missionary.

Ebola, according to the World Health Organization, is a disease with a “case fatality rate of up to 90 percent,” passed through close contact and bodily fluids. It has claimed more than 600 lives in Liberia, Nigeria, Sierra Leone, and Guinea in an outbreak that health officials believe may have originated in the latter country as early as January, according to AP reporting.

Dr. Kent Brantly of Franklin Graham’s North Carolina-based aid organization Samaritan’s Purse, is in stable condition after contracting the disease while treating patients in Liberia, according to the organization.

[A Samaritan’s Purse spokesperson] cautions that Brantly, 33, is “not out of the woods yet.” She says patients have a better chance of survival if they receive treatment immediately after being infected, which Brantly did.

The Associated Press found a prescient quote of Brantly’s from earlier this year:

Health workers are among those at greatest risk of contracting the disease, which spreads through contact with bodily fluids.

Photos of Brantly working in Liberia show him swathed head-to-toe in white protective coveralls, gloves and a head-and-face mask that he wore for hours a day while treating Ebola patients.

Earlier this year, the American was quoted in a posting about the dangers facing health workers trying to contain the disease. “In past Ebola outbreaks, many of the casualties have been health care workers who contracted the disease through their work caring for infected individuals,” he said.

Nancy Writebol, a missionary from North Carolina, is very ill and in isolation according to the pastor of her church.

But here’s the pair of headlines that made me start wondering where this is headed:

Nigeria government confirms Ebola case in megacity of Lagos

A Woman With Ebola Escaped Quarantine And Is On The Run In A City Of 1 Million

Lagos is a city of 21 million people, the largest on the continent of Africa. The city has shut down the hospital in which he died for decontamination and identified 59 people with whom he had contact, though the airline on which he flew doesn’t seem to have yet provided a list of passengers, whom a virologist interviewed by Reuters deemed in “pretty serious danger.”

The Nigerian city of Lagos shut down and quarantined on Monday a hospital where a man died of Ebola, the first recorded case of the highly infectious disease in Africa’s most populous country.

Patrick Sawyer, a consultant for the Liberian finance ministry aged in his 40s, collapsed on arrival at Lagos airport on July 20. He was put in isolation at the First Consultants Hospital in Obalende, one of the most crowded parts of a city that is home to 21 million people, and died on Friday.

“The private hospital was demobilized (evacuated) and the primary source of infection eliminated. The decontamination process in all the affected areas has commenced,” Lagos state health commissioner Jide Idris told a news conference.

Some hospital staff who were in close contact with the victim have been isolated. The hospital will be shut for a week and all staff closely monitored, Idris added.

Reuters also reports doctors in Nigeria, one of the African countries better positioned to control an outbreak, are on strike over pay issues and have no plans at this point to call off the work stoppage. Liberia is reportedly locking down its border crossings, but many health officials remain concerned most of the countries where outbreaks are occurring simply don’t have the security or the infrastructure to really prevent spread.

And, now a final headline to chill your blood.

Ebola only a plane ride away from the U.S.: Ebola could easily arrive in the USA on board a plane, but wouldn’t spread far, experts say.

So, we got that going for us, which is nice.