US health officials monitoring possible Ebola exposure, as airline stocks fall

US health experts are monitoring “a handful” of individuals who could have been exposed to Ebola by coming into contact with the first patient diagnosed with the disease in the US.

A man who flew from Liberia to Texas was confirmed to have tested positive to Ebola on Tuesday, the first confirmed case of contagion in the US.

On Wednesday, Texas health officials said healthcare workers tested negative for the virus and there were no other suspected cases to report, though they added workers will be under observation for the next 21 days.

"We have a seven-person team in Dallas today helping to review that with the family and make sure we identify everyone that could have had contact with him," Dr. Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC), said in an interview with NBC TV's "Today" show.

It can take up to three weeks for the symptoms of the hemorrhagic fever, which spreads through contact with bodily fluids like blood or saliva, to appear.

While the chances of the virus spreading are smaller than in the case of airborne diseases, the period of time before symptoms such as vomiting and fever begin to manifest means an infected individual can potentially travel a long distance without being detected.

Past outbreaks had a mortality rate of 90%, while the current outbreak has so far killed about 50% of those who have contracted the virus.

"If you have someone who's been in West Africa in the past 21 days and they've got a fever or other symptoms that might be consistent with Ebola, immediately isolate them, get them tested," Frieden said.

US health authorities said that all the necessary actions were being taken to ensure Ebola does not become a nationwide issue and they remained confident that the virus can be limited and contained.

"People can be confident here in this country that we have the medical infrastructure in place to prevent the broad spread of Ebola," White House spokesman Josh Earnest told CNN.

News of the virus arriving in the US has seen airline stocks fall sharply on Wednesday, as investors were concerned that news of the first case in Texas could discourage people from flying.

Delta Air Lines fell 3.7%, United Continental dropped 3.6%, while American Airlines and JetBlue both shed 3.1%.

However, shares in pharmaceutical companies working on Ebola treatments rose, with Tekmira Pharmaceuticals surging 22% and BioCryst Pharmaceuticals and Sarepta Therapeutics rising 6.34% and 8.06% respectively.

Shares of International Airlines Group, one the world's largest trans-Atlantic carriers, was also off sharply on Wednesday, closing 2.7% lower in London trading, at 357.2p.