CLEVELAND (AP) -- The Cleveland Metroparks Zoo says its oldest African elephant has been euthanized after falling ill.

The zoo says keepers found the 45-year-old female elephant named Jo lying down and unable to get up on Monday.

Zoo director Steve Taylor calls it a "heart-wrenching situation" and says the team made a humane decision. The elephant recently had been suffering from a type of swelling.

Jo was born in Mozambique in 1967 and arrived at the Cleveland zoo 15 years ago from a facility in Oregon. The 7,500-pound elephant was one of six in a popular exhibit where visitors can watch keepers interact with elephants and learn about them.