The story is now all over the world media; here's a report in The Guardian with a few more details: Ebola crisis: US doctor working in Liberia tests positive. Excerpt:
A US doctor working with ebola patients in Liberia has tested positive for the deadly virus.
The aid organisation Samaritan's Purse issued a news release on Saturday saying Dr Kent Brantly was being treated at a hospital in Monrovia, the capital. Brantly had been serving as medical director for the aid organisation's case management centre there.
Samaritan's Purse spokeswoman Melissa Strickland said Brantly's wife and children had been living with him in Africa, but were now in the US.
Brantly was quoted in a posting on the organisation's website earlier this year about efforts to maintain an isolation ward for patients.
"The hospital is taking great effort to be prepared," Brantly said. "In past ebola outbreaks, many of the casualties have been healthcare workers who contracted the disease through their work caring for infected individuals."
The report also mentions the case of Patrick Sawyer, the Liberian who was isolated immediately upon his arrival in Lagos. Apparently he had no symptoms when he boarded his flight in Monrovia. The 50 other passengers are being monitored but are not in isolation.