Defra has confirmed the presence of the deadly Koi Herpes Virus at two fisheries in southern England.
Samples of fish taken from Canvey Lake at Canvey Island, Essex, and River Park Farm Fishery at Lodsworth, West Sussex, were found to have the virus this week after the owners reported the suspicious deaths of carp stocked at the premises.
Defra has issued a Designated Area Order at each fishery which prohibits fish movements in an effort to prevent the spread of the disease.
The outbreaks are among the first to be formally reported this year, after the disease became notifiable on April 6 this year.
While in previous years fishery owners have often not reported outbreaks, there is now a legal obligation to do so and the authorities have greater powers to close fisheries to prevent the disease spreading.
The first Designated Area Order was placed on Kingsdown Flash, near Wigan in Lancashire last month.