Although privacy experts worry about the government gathering personal information on airline travelers, Delta Airlines (DAL) is handing over electronic lists of passengers from some flights to help stop the spread of deadly infectious diseases.

The lists will allow health officials to notify more quickly those travelers who might have been exposed to illnesses such as dengue fever, flu, plague, SARS (search) and biological agents, the Centers for Disease Control and Prevention (search) told a congressional panel on Wednesday.

"The government is seeing that massive amounts of data can be useful for any number of purposes," said Marcia Hofmann, an attorney for the Electronic Privacy Information Center (search). "There need to be some regulations or restrictions on how airlines can share passenger information like this."

Passenger lists already are sent electronically to the Customs Bureau (search), which checks to see if any potential terrorists are aboard flights bound for the United States. The CDC wants access to the same lists, but only for flights coming from places with an outbreak of an infectious disease or for those that carried a passenger later found to be infected.

Now, the CDC must gather passenger names by hand from flight manifests, Customs declarations and other sources, which can take time, said Dr. Anne Schuchat, acting director of the CDC's National Center for Infectious Diseases (search).

Electronic access to all the information would help considerably in speeding the notification process, she told the House aviation subcommittee during a hearing about preventing the spread of diseases through the global aviation system.

Schuchat said Delta has agreed to share the information on a test basis.

Infectious illnesses have long been transported by airplanes. With the outbreak of more virulent strains of communicable diseases and the volume of international travel, U.S. health officials worry planes could greatly hasten the spread.

Last week President Bush signed an executive order authorizing the government to quarantine people to deal with any outbreak of new strains of flu, including "bird flu," a particularly lethal variation of influenza now found in Southeast Asia.

CDC aims to prevent a pandemic in the United States through surveillance, early detection and swift response, Schuchat said. Rapidly tracking down exposed airline passengers is part of that effort.

An airline representative said the industry supports the CDC's goal but has concerns about data privacy, incompatible computer systems and questions about whether other nations will reciprocate.

The same issues are raised in debates about transmitting passenger lists on international flights to Customs, or turning over personal data about passengers to the Transportation Security Administration (search) to screen for terrorists, said John Meanen, executive vice president for the Air Transport Association of America (search), which represents major airlines.

As an example of the CDC's notification efforts, Schuchat cited the case of a New Jersey resident who returned from a trip to Sierra Leone in September with Lassa fever (search). The patient flew to Newark via London and took a train home. Only after he died a few days later did the CDC confirm the disease.

CDC worked with the state, the airline, the railroad, the hospital and others to identify 188 people who had been near the patient. Nineteen were deemed at-risk and 16 were contacted; none of those contacted came down with the disease. It took more than five days to notify some passengers, Schuchat said.

The incident, said Schuchat, "highlights how increased international air travel contributes to a need for enhanced preparedness to detect and respond to emerging infectious disease threats."

Delta did not return a telephone call seeking comment.