The U.S. Centers for Disease Control and Prevention said the patient diagnosed with Ebola in the U.S. disclosed that he flew part of his trip on United Airlines, the airline announced Wednesday afternoon.
The CDC said there was "zero risk of transmission" on any flight on which the patient flew because he was not symptomatic until several days after his trip.
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The patient, who arrived in Dallas from Liberia, is believed to have flown United Airlines from Brussels to Washington Dulles on Flight 951 and Washington Dulles to Dallas-Fort Worth on Flight 822.
"We are ensuring our employees have this information and suggest that any customers who have concerns contact the experts at the CDC for further information," United said, noting that it was not required to divulge the information.
Shares of United and other global airlines ended the session sharply lower on Wednesday.
"African travel isn't a huge part of the travel industry, but it does seem like some parts of the industry are likely to be disrupted from this," RiverPark Advisors' Mitch Rubin told Reuters.
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Shares of Delta and Southwest closed more than 3 percent lower, while United Airlines and Ryanair Holdings closed more than 2 percent after falling as much as 4 percent in earlier.
The NYSE Arca Airline index and the Dow Jones Transportation Average were both down more than 2 percent.
The Dow fell more than 1 percent, with Boeing and United Technologies among the hardest hit, with declines of 2 percent and 1.7 percent, respectively.
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The CDC on Tuesday said the patient arrived in the U.S. from Liberia on September 20th about four days before seeking medical care.