But Ringling Bros. and Barnum & Bailey Circus and government health officials say the animal is not a threat because she does not have an active form of the infectious disease, The Baltimore Sun reported Thursday.
The U.S. Department of Agriculture calls for quarantining elephants only if they have an active case of TB.
Elephant-to-human transmission of TB is a new field of study, only officially confirmed in 2009 by a Centers for Disease Control and Prevention study of an outbreak in Tennessee when TB was transmitted from an elephant to nine workers at an animal refuge.
People for the Ethical Treatment of Animals discovered last week the 42-year-old Asian elephant named Karen had a positive TB blood test, Delcianna Winders, the group's director of captive animal law enforcement, said.
Winders said she informed Baltimore animal control officials Monday and was told the city would bar the circus from using Karen.
Later, Winders said, the city reversed itself and said the animal could perform.
One of the authors of the CDC study said there was little risk to the public.
"If you're at a circus, you're at a great distance from the elephants," said Dr. William Schaffner, chairman of the Department of Preventive Medicine at the Vanderbilt University School of Medicine. "You do not have genuinely prolonged contact with them. You're there for two hours of the show. That sort of exposure should not put people at risk.
"I would let my grandchildren attend," he said.