An Asian elephant who was cured of heroin addiction in southwest China has been declared unfit for the wild, local zoo keepers said on Sunday.

Four-year-old male Xiguang (L) in this file photo undated. [sohu.com]

Four-year-old male Xiguang and five other elephants became the targets of illegal traders at the China-Myanmar border in March 2005. Among the beasts, Xiguang, was fed with bananas smeared with heroin by the smugglers who intended to snare the animal.

The elephants were captured by police two months later. Four of them, including Xiguang, were later sent to a wild animal protection center in the southern Hainan Island.

Xiguang was cured of his addiction after a three-year treatment that included methadone injections five times stronger than human doses.

The four elephants were brought back to the Yunnan Wild Life Park last month and will spend the winter at the Xishuangbanna Wild Elephant Valley in Yunnan.

"Three years of domestic life and a huge amount of rehabilitation medication has changed the physical situations, odors and habits of Xiguang and the other elephants," said Pan Hua, the park's deputy manager.

"They may become the target of attacks by other beasts if they are sent back to the wild. Some are easily irritable now and may hurt humans. They can't go back to the wild anymore," he said.

The elephants will stay in the valley and be cared for by zoo keepers.