A second man who contracted the virus is being sent to Nebraska

The first person diagnosed with Ebola in the United States was fighting for his life at a Dallas hospital, a top US health official said, adding that one of the experimental medicines for the virus was not available, while another carries risks that were being weighed by the victim's family.

Thomas Eric Duncan became ill after arriving in Texas from Liberia two weeks ago, heightening concerns that the worst Ebola epidemic on record could spread from West Africa, where it began in March. The hemorrhagic fever has killed at least 3,400 people out of the nearly 7,500 cases that were confirmed, probable or suspected.