Federal health officials are scrambling to find the family, friends, and anyone who may have come into contact with a man who was diagnosed with the first U.S. case of Ebola virus.

Centers for Disease Control and Prevention Director Dr. Tom Frieden said Tuesday the man arrived in Texas from Liberia earlier this month, but he showed no symptoms while on the plane.

Officials "don't believe there is any risk to anyone who was on the flight at that time," Frieden told reporters and the Associated Press.

The patient came to the United States on Sept. 20 from Liberia to visit family. He sought care last Friday, and he has been in isolation since the weekend.

There are no other suspect cases of Ebola in Texas, officials said.