Karen, a 42-year-old Asian elephant, tested positive for TB in a blood test but negative in a follow-up test known as a trunk wash, which involves taking a culture of saline solution run through the animal's trunk.
U.S. Department of Agriculture, which calls for quarantining elephants only if they have an active case of TB.
Elephant-to-human transmission of TB is a very new field of study — that it occurs at all was only officially established in 2009 by a Centers for Disease Control and Prevention study, prompted by the outbreak at the Tennessee refuge — and experts are still trying to determine the best way to deal with the problem, said Dr. William Schaffner, chairman of the Department of Preventive Medicine at the Vanderbilt University School of Medicine and one of the authors of the CDC study.
"This is a large gray area," Schaffner said, borrowing a line from one of his co-authors, Rendi Murphree, an epidemic intelligence service officer at the CDC and a visiting scholar at Vanderbilt. The USDA is holding a meeting in Kansas City this very week to discuss the matter.
"Could an elephant have a positive MAPIA [blood] test and a negative trunk wash and still be infectious? Is that possible?" Schaffner said. "That's where the current scientific discussion lies. How reliable is a negative trunk wash test? That is a legitimate area of discussion. There are people that say every elephant with a positive MAPIA should be held back under infection control precautions — quarantined, if you will — and treated. Others say it's not necessary."
Even given all the unknowns, Schaffner thinks that there is little risk of a spectator at the circus becoming infected from an elephant.
"If you're at a circus, you're at a great distance from the elephants," he said. "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."
He added: "I would let my grandchildren attend."
People for the Ethical Treatment of Animals discovered late last week that Karen had a positive TB blood test and had been barred from Tennessee, in documents it obtained through a government Freedom of Information request, said Delcianna Winders, the group's director of captive animal law enforcement. Winders said she forwarded the information to Baltimore animal control officials Monday and that someone there initially told her the city would bar the circus from using Karen. Later, Winders said, the city reversed course and said the animal could perform.
The animal-rights group sent an email to The Baltimore Sun on Wednesday morning headlined: "PETA Applauds City of Baltimore for Pulling Ailing Ringling Elephant From Performances." A few hours later came a follow-up from PETA: "TB-Infected Elephant Put Back Into Circus Ring — Humans Put at Risk."
City officials said that there was no about-face and that they reached their conclusion after consulting with appropriate state and federal experts.
"There are established USDA standards by which the potential disease risk is assessed, and this particular case does not meet these standards," the city Health Department said in a prepared statement. "The decision to allow Karen the elephant to perform at First Mariner Arena in Baltimore City was based on careful consideration of many factors, including veterinary evaluation of the elephant's health records. Based on all the information obtained, and in consultation with DHMH, MD Department of Agriculture and the US Dept of Agriculture, Baltimore City HD has determined that Karen the elephant can participate in scheduled performances in Baltimore."