A U.S. doctor who was helping Taiwan battle SARS (search) left the island on a charter flight Friday after developing a fever and other symptoms possibly caused by the virus.

An ambulance with flashing red lights drove the American physician who works for the Centers for Disease Control and Prevention (search) from a hospital in the capital, Taipei, to the city's domestic airport.

The doctor boarded a business jet for the flight back to the United States. Taiwanese and U.S. officials did not speak to reporters and gave no U.S. arrival time for the flight.

The physician was Chesley L. Richards Jr., an infection control expert, said Stephen Kuo, spokesman for Taiwan's SARS Control Committee. The CDC did not identify him by name.

Local TV stations showed the doctor getting into the ambulance. He wore a white protective gown with a hood, a pink cap, face mask and a clear plastic shield over his eyes. He boarded the plane without assistance.

He arrived May 15 and had visited the emergency rooms and intensive-care units at two Taipei hospitals where SARS outbreaks were reported, Taiwanese officials said.

This week, he developed a fever and a cough — common SARS symptoms, CDC director Dr. Julie Gerberding (search) told reporters Thursday at the centers' headquarters in Atlanta.

If he has severe acute respiratory syndrome, he would be the second disease investigator sent from abroad to catch SARS. The first victim was Dr. Carlo Urbani, an Italian.

Urbani, a WHO communicable disease expert based in Hanoi, Vietnam, was the first person to identify SARS and to alert the world of its potential dangers. He died of the disease in Bangkok, Thailand.

Earlier Friday, Taiwan reported 55 new cases but no new deaths. The island's total number of infections was 538 and the death toll is 60.

The U.S. physician was staying at the Sheraton Taipei Hotel, which was sealed off immediately after he was reported ill. Nine restaurant workers and four cleaning staff have been quarantined.

The doctor's illness has not been listed as a probable SARS case because an X-ray did not indicate he had pneumonia, Gerberding said.

But his fever and cough symptoms were enough to classify him as a suspected case, Gerberding said.

Taiwanese officials also said the man did not test positive for the new type of coronavirus believed to cause SARS, but the test is not always accurate.

Gerberding said that three other CDC employees who have taken care of the sick physician and may be exposed to whatever ailment he has will leave with him and should be in Atlanta by Sunday.

Dr. Lee Ming-liang, head of the Taiwan SARS Control Committee, told reporters that the doctor's departure from Taiwan was not a no-confidence vote for Taiwan's medical system. Evacuating ill workers is a common CDC policy, Lee said.

"It's not that they don't trust us," Lee said. "This is very normal."

Taiwanese officials said the WHO will send two new doctors to Taiwan this weekend to maintain a staff of three.