Heroin smugglers were using the animals to carry vast quantities of the drug across the border between China and Myanmar, also known as Burma, and fed them opium to make them follow orders.But after the gangsters were caught and their elephants were sent to a sanctuary, keepers discovered some of the animals had become restless and wildly aggressive.Staff at the Wild Elephant Valley in Yunnan Province, China, ran tests on drug-running elephants joining their reserve on separate occasions over the last nine years.In total, four had traces of heroin in their system.Each elephant was given a lengthy course of methadone lasting up to a year - and keepers have now announced that all four are drug-free.They are so confident of the animals' health that they have released them back into wild herds.Elephant breeder Chen Jiming, who helped the elephants kick the habit, said: 'It has been a long battle but we can safely say that they are now reintegrated into elephant society and in some cases even have families of their own.'He added that there needed to be a change in the law.'There are actually more elephants now in the wild since China made it a crime punishable by death to hunt them,' he said.'But we haven't increased the penalties for people who turn them into drug addicts by feeding them heroin laced bananas.'This is also an important issue that needs to be tackled.'The elephants were used to carry heavy quantities of drugs across the border in packages on their backs.Smugglers from China's feared Triad gangs would give the animals drugs to make them more pliant and docile, making them easier to train.Once the animals were addicted to the tainted fruit, they would become desperate for the next fix and obey any command by a gang member as long as they were adequately rewarded.Because trainers had never tried to cure an elephant's addiction they decided to use methadone, the same treatment given to humans.The drug, which is an opiate like heroin but without the buzz associated with the drug, was given to the animals in slowly-diminishing amounts over the course of a year. All four elephants now live in the forests of Yunnan Province in south-western China, a protected area which is home to another 250 wild elephants.  Mr Chen added: 'The elephants need at least five times more methadone than a human being would need at the start, and then we slowly reduced that until they no longer needed it.'It is every bit as hard for the elephants to go through the cold turkey regime as it is for humans.' (dailymail.co.uk)Bakudaily.az