Italian officials said Wednesday they were tracing the movements of an American man infected with a rare and dangerous form of tuberculosis who honeymooned in Rome for two days despite being told to turn himself in to health authorities.

The man, who Italian authorities said was 32 years old, is hospitalized in respiratory isolation in an Atlanta hospital.

He flew from Atlanta to Paris, and then on to Greece, where he says he got married, before catching flights to Rome, Prague and Montreal before driving into the United States, officials aid. The U.S. Centers for Disease Control and Prevention contacted him in Rome and told him to turn himself in to Italian authorities to be isolated and treated.

The World Health Organization said Wednesday the chances that the man infected fellow passengers was small, although officials noted that because of TB's long incubation time, it may be years before anyone knows whether the man infected anyone while he was traveling.

Dr. Olivia Callipari of the Italian Health Ministry said local authorities were informed by CDC officials that the infected passenger had passed through Italy last week.

"As a precaution, we have set up a surveillance system and are tracing all his movements," including the flight he boarded to Prague and the hotel where he stayed during his nearly two-day stay in Rome, she said.

"We have identified all the passengers sitting within two rows in front and behind his seat on the plane and are working to inform them," about the potential health risk, Callipari told The Associated Press. She said the patient did not show any symptoms of the infection during his stay in Rome.

The infected patient flew from Atlanta to Paris on May 12, arriving May 13 on Air France Flight 385. The next day, he traveled on Air France Flight 1232 from Paris to Athens, one of 152 passengers.

He remained in Greece until May 21, said Yiannis Pieroutsakos, director of the Greek Center for the Control and Prevention of Diseases. He then traveled to Rome, where he stayed until leaving for Prague on May 24 aboard Czech Air Flight 727, airline spokeswoman Daniela Hupakova said.

Later on May 24, he took Czech Air Flight 410 from Prague to Montreal, then drove into the United States, according to the CDC.

Meanwhile, Air France-KLM has been asked by French health authorities to provide lists of all passengers seated within two rows of the infected man, a spokeswoman said.

She said that Air France uses high-efficiency particulate air filters on its planes, which mean that 50 percent of the air circulating is new and 50 percent is recycled.

French health officials said they would give a passenger list of the May 13 flight to their counterparts abroad — leaving it to them to decide how to inform passengers from their countries.

Pieroutsakos, the Greek health official, said the U.S. Embassy in Athens alerted Greek authorities about the man only after he had left. He said Greek officials were "obviously watching this closely."

Tuberculosis usually affects the lungs, and can lead to symptoms such as chest pain and coughing up blood. Caused by germs that are spread from person to person through the air, it kills nearly 2 million people each year around the world.

The man in question is believed to have the rare and "extensively drug-resistant" TB — or XDR-TB — which does not respond to at least three of six classes of second-line drugs.

Nevertheless, the WHO said the risk of transmitting XDR-TB on the flights would have been low.

"It's a small risk, but it's not zero," said Dr. Mario Raviglione, director of WHO's Stop TB department. It's the long-haul flights (eight hours or more) that would have been most dangerous, the short flights were too short for the infection to be passed easily, he said. "The risk exists, but he was not highly infectious."

The risk of infection is related to the infectiousness of the TB patient, the duration of exposure, proximity to the source, and the conditions of ventilation and crowding. The quality of air on an airplane is generally high, and under normal conditions, cabin air is cleaner than that in most buildings.

Raviglione said that there have never been any documented instances of TB transmission on airplanes. But because the incubation period for TB can vary from a couple of weeks to a few decades, it will not be known for a long time if anyone gets TB from the man's travels.