ST. LOUIS — One of the most popular residents of the St. Louis Zoo is being treated for tuberculosis, but zoo officials say the prognosis is good.

Ellie is a 46-year-old Asian elephant and the mother of three other elephants living at the zoo.

The zoo’s director of animal health, Luis Padilla, said in a statement Thursday that the illness was detected early through routine blood tests and a trunk culture. Other elephants in her family are being monitored.

Ellie is not showing symptoms.

The zoo says TB occurs occasionally in elephants and can be treated successfully. Another elephant at the zoo, Donna, was treated successfully about five years ago.