South Korean quarantine officials are set to slaughter 386,000 poultry after an outbreak of a highly pathogenic version of bird flu, the agriculture ministry said Saturday. The outbreak occurred at a chicken farm in Cheonan, about 92 kilometers south of Seoul, earlier this week, the fifth such outbreak since November, said Lee Joo-won, a ministry official. The official said it would take some time to confirm whether the virus is the deadly H5N1 strain of bird flu. South Korea culled 5.3 million birds during the last known outbreak of bird flu in 2003. The H5N1 virus began ravaging Asian poultry stocks in late 2003 and has killed more than 160 people worldwide. Most human cases have resulted from contact with infected birds. Scientists fear the virus could mutate into a form that is more easily transmitted between people, possibly creating a pandemic that could kill millions.