A spokeswoman for the Department of Health has said schools will not be closed, even though a fourth child has died of a mystery illness. Health authorities are investigating the death of a Shau Kei Wan six-year-old girl, who died on Wednesday, after being sent home from the emergency unit of Pamela Youde Nethersole Eastern Hospital. She was stable when she was discharged, but she saw a private doctor on Wednesday for a persistent fever and was being taken back to the hospital emergency unit when she suffered convulsions. She was not breathing and had no pulse on arrival and was certified dead at 8.43pm. A spokesman for the Centre for Health Protection said initial laboratory tests on a specimen from the girl's respiratory tract yielded negative results for influenza and other possible causes of death. The girl had visited Guangzhou and Shenzhen last month.