“Swamp fever” continues to claim victims in Ireland with another two cases confirmed last week, bringing the total to 24.
Although the Irish Department of Agriculture admitted to H&H that Equine Infectious Anaemia (EIA) or swamp fever is or was spreading via biting insects, it stressed all cases can still be linked.
“What we do not have at the moment is an isolated case on its own — that would be much more concerning,” said Tom Myers, a superintendent veterinary inspector for the department. “I believe all the cases are linked to known sources — a couple might appear to be out of the loop but they are all linked.”
About 1,100 horses have been quarantined. Work is ongoing to establish the source of outbreak but it is believed to stem from plasma illegally imported from Italy. Mr Myers said exactly how many foals may have been treated with the plasma is unconfirmed.
Swamp fever was not known in Ireland before this summer, but Mr Myers said at least two horses died from an “unknown condition” before a mare died at Troytown Veterinary Hospital in Co Kildare on 14 June, and the disease was identified. Since then, 20 cases have been linked to Troytown or other studs which may have used the Italian plasma.
Four more cases, one a non-Thoroughbred confirmed last week, are not part of the surveillance programme, indicating that the plasma may have been used more widely.
“There has been evidence of transmission through biting insects. But it is only thought to have been the cause of infection where horses have been kept in close proximity, where one had been exposed to infection via another route,” said a spokesman for the department of agriculture. “Threat of transmission this way is decreasing as the weather gets colder.”
Troytown was reopened in August after sterilisation. The hospital’s partner Hugh Dillon said: “There has been and is no reason for panic, but there is no reason for complacency either. There have been record sales at Goffs, with many buyers from UK.”
The World Organisation for Animal Health last week confirmed an outbreak of swamp fever in Germany — the first in four years — where 10 horses have died and another 34 have been identified with the disease or at high risk of infection.
The cases, and the strain of swamp fever introduced in Ireland from the Italian plasma, are reportedly traceable to Eastern Europe.
“People must remember that swamp fever is endemic in Eastern Europe and with the movement of horses in Europe, they have to be extremely vigilant,” said Mr Dillon.
The estimated cost of the outbreak in Ireland is still unknown. The government is paying for testing for restricted animals, plus a contribution to vets call-out fees. All horses entering any sale in Ireland must produce a negative Coggins test [the definitive test for the disease].
No cases of swamp fever have been found in mainland UK to date. While all racehorses from Ireland must produce a negative Coggins test to run in the UK, a DEFRA spokesman said there were no plans to introduce routine Coggins testing for all horses coming from Ireland to the UK.