The U.S. Centers for Disease Control and Prevention are trying to track down passengers who may have been exposed to a woman infected with a multi-drug-resistant strain of tuberculosis on American Airlines Flight 293 between New Delhi and Chicago on December 13.
According to this Scientific American article, health authorities are looking for 44 passengers who sat within two rows of the woman, and also for the crew members working in the cabin.
The woman later flew on a shorter flight between Chicago and California, but authorities aren't searching for passengers from this plane because they say, "there is only a minimal chance of infection during a short duration flight."
If this sounds familiar, it's because this is the second time in a year a person infected with hard-to-treat TB has taken a long-haul flight and exposed other passengers to the disease.
The CDC has more information about the risk of in-flight disease transmission.