The Centre for Health Protection is investigating a case of necrotising fasciitis affecting a man aged 56.
He fell ill on September 15 and was admitted to Pamela Youde Nethersole Eastern Hospital on September 17.
He tested positive for Vibrio vulnificus, a type of bacteria which can cause necrotising fasciitis, and his left leg was amputated.
He is in critical condition.
He has no recent travel history and his home contacts are asymptomatic. Investigations are proceeding.
