As the Department of Agriculture confirmed two new cases of Equine Infectious Anaemia (EIA) in horses, it insisted that it has the disease, commonly known as swamp fever, under control.
It said the two most recent cases were related to earlier cases and were among a small group of horses categorised by the department as being at "high risk" for the disease.
This brings to 14 the number of cases confirmed to date. In addition, the number of premises now restricted is 17 and some 480 horses have been restricted.
The disease, which had never been found in this country before, has now spread to a number of counties beyond Meath and Kildare, where the original outbreak was confirmed.
It is understood cases have now been identified in Co Limerick and the horses involved were in contact with the first two cases, a mare and her foal, who may have got the disease from infected equine serum being used for the treatment of another horse disease.
Swamp fever can also be spread by the use of infected instruments.
EIA is an exclusively animal health issue with no public health consequences. It is usually transmitted mechanically, most commonly through blood-sucking insects (tababus or stomoxys species) or through the use of blood-contaminated instruments or needles.
While the tababus or stomoxys species are not native to this country, transmission of the disease may occur where there are large numbers of horseflies in proximity to acutely affected horses and occurs most often during periods of high insect activity, in low-lying swampy areas close to woodlands. Transmission of infection via colostrums or semen is uncommon.
The department believes it has traced the horses which, over the past few months, were in contact or passed through the farms on which the infected animals were located.
An outbreak of the disease here would have very serious consequences for the bloodstock industry and could lead, if it were to get out of control, to the cancellation of racemeetings and horse shows.