US health officials are seeking 132 people who flew on a plane with a Texas nurse on the day before she came down with symptoms of Ebola.

The nurse, the second person to catch Ebola in the US, fell ill on Tuesday.

Both she and nurse Nina Pham, 26, had treated Liberian Thomas Eric Duncan, who died on 8 October, in Dallas.

Meanwhile, the UN's Ebola mission chief says the world is falling behind in the race to contain the virus, which has killed more than 4,000 in West Africa.

Today, the US Centers for Disease Control and Prevention (CDC) said it wanted to interview the people who flew on Frontier Airlines flight 1143 from Cleveland, Ohio, to Dallas, Texas on 13 October.

It said it was taking the measure "because of the proximity in time between the evening flight and first report of illness the following morning".

The nurse, who has yet to be identified, was not showing symptoms of the disease when she flew, the crew has told CDC investigators.

Health experts say people who are not showing symptoms are not contagious.

On the morning of 14 October, the nurse came down with a fever and was isolated within 90 minutes. Her diagnosis was announced early today.

Both the nurse and Ms Pham treated Mr Duncan at Texas Health Presbyterian Hospital in Dallas and were exposed to the virus then.