A new case of the deadly "swamp fever" virus detected in a horse in the east of Ireland has brought the number of cases discovered to 21, it was confirmed today.
The North's Agriculture Department said it was investigating the circumstances of the latest case of Equine Infectious Anaemia (EIA), also known as "swamp fever", which was detected in a horse on a previously unrestricted premises in Co Derry.
The premises had not been part of the department's surveillance and control programme of at-risk locations which has been under way since the middle of June.
A spokesman said the premises had since been restricted, which brings to 23 the number of places under restriction. Work is already under way to trace other horses which may have been in contact with the animal.
The department also said another three cases were confirmed in the past week in horses which had previously been identified as high-risk animals. EIA has been detected in a small number of horses after it is believed some foals were injected with infected serum.
The spokesman called on horse owners and those involved in the industry to continue to be vigilant and maintain high standards of biosecurity. It recommended any horses presenting with the clinical symptoms suggesting swamp fever should be immediately blood sampled and tested for the disease.
At the start of this month, a prize foal was put down after confirmation of the first case of swamp fever among horses in Northern Ireland.
Restrictions were placed around the Co Derry premises. There is no known cure and any animals which test positive for the virus, which spreads between horses, donkeys and mules, are generally culled to prevent it spreading further. The virus is usually transmitted through blood-sucking insects or through the use of contaminated instruments or needles.
Horses infected with the EIA virus may take up to three weeks to show clinical signs of the disease, which include intermittent fever, small haemorrhages in the mucous membranes, anaemia, swelling and death. The disease cannot be transmitted to humans.