The father-in-law of a U.S. man quarantined for a drug-resistant form of tuberculosis will be investigated by the Centers for Disease Control and Prevention, where he works as a microbiologist studying the disease, the agency said Saturday.

The patient, Andrew Speaker, is the first person placed under U.S. federal quarantine since 1963. He has asked for forgiveness for sneaking on board two transatlantic flights to Europe and Montreal, even though he was aware he carried highly drug-resistant TB and had been warned by U.S. health officials not to travel.

Speaker, a newlywed, was also told to stay put in Rome by U.S. doctors who contacted him and said further tests showed he actually had a more dangerous type of TB than had been previously thought. But he later took flights to Prague and then attempted to slip back into the U.S.via a flight to Montreal.

The personal injury lawyer, 31, said he was initially told that he wasn't contagious or a danger to anyone. Speaker said officials never forbade him from travelling, but only said they would rather he not make the trip.

His father-in-law, Robert Cooksey, whose specialty at the CDC is TB and other bacteria, has said he provided "fatherly advice" to Speaker about travelling with the illness.
  
Federal health officials said Friday that Cooksey had helped to find Speaker and diagnose his condition. They would not give any more information about the investigation.

Speaker has said he made the journeys despite the warnings because he feared he wouldn't survive if he didn't reach the U.S.

Could face surgery

Speaker was quarantined May 25, a day after he was allowed to pass through the border crossing at Champlain, N.Y.

In an interview with ABC's Diane Sawyer on Good Morning America this week, Speaker apologized to the people travelling with him for potentially exposing them to the infectious disease. 

Speaker settled in Saturday for what could be a two-month hospital stay by taking antibiotics and fielding phone calls. He had breakfast and spent much of the day on the phone with well-wishers, his nurses at National Jewish Medical and Research Center reported.

Speaker was taking antibiotics to battle a tennis-ball-size infection in his lung, hospital spokeswoman Geri Reinardy said.

Doctors said his treatment could include surgery to remove the infected tissue if the drugs don't work.

Tests so far indicate Speaker's risk of spreading the infection are low, doctors said.

Doctors hope to determine where Speaker contracted the disease, which has been found around the world and exists in pockets in Russia and Asia.

Health officials have contacted 160 of the 292 U.S. citizens who were on the May 12 Atlanta-Paris flight, according to the CDC. That count includes all 26 who sat in the five rows around Speaker — those considered at greatest risk.

With files from the Associated Press