The second infection of a United States healthcare worker who treated the country's first Ebola patient has exposed a series of gaps in its preparedness for confronting the deadly virus.
President Barack Obama said last month the US was ready for the "unlikely event" that the haemorrhagic virus ravaging West Africa could make its way into the country, and that any emergence would be quickly contained.
But when a Liberian man with a fever, body pains and recent history of travel to the country worst-hit by the current epidemic first walked into a Dallas hospital on September 25, he was sent back home after about four hours.
That decision put other emergency room patients, the man's family and hospital staff at risk of exposure to Ebola.
When he was rushed via ambulance back to that same hospital on September 28, vomiting and experiencing diarrhoea which made him highly contagious, dozens of healthcare staff may have been infected by not adequately protecting themselves.