Dr. Graham Crawshaw, the zoo's senior veterinarian, said zoo officials learned of the tuberculosis problem while conducting a due diligence investigation of the PAWS sanctuary, the Toronto Star reported. He said the zoo is still seeking updated test results from the Northern California facility, where five of eight elephants have tested positive for TB.
"It's more than reasonable to assume there is active TB in Asian elephants at PAWS," Crawshaw said.
Eight elephants have died at PAWS since 2003, including two Asian elephants that tested positive for TB. It wasn't clear whether any of the African elephants that died had tested positive, the newspaper said.
Toronto's three females -- Iringa, Toka and Thika -- are African elephants.
Julie Woodyer of animal-rights group Zoocheck Canada, which is working to achieve the transfer of the Toronto animals to PAWS, said the zoo staff has shown "significant bias" against PAWS and has been under "pressure" from the U.S. Association of Zoos and Aquariums not to send them to the unaccredited facility.
The zoo lost its AZA accreditation this past spring.