The Dublin hospital where a man with suspected vCJD is being treated has effectively ruled out the possibility that his condition might have been caused by a blood product.
The hospital said in a statement: "In the public interest, the hospital can confirm that the patient never received a blood transfusion or made a blood donation, and that the cause of infection is not linked to an operation."
Given that blood has been ruled out as a possible source, the man's infection is likely to be traced back to contaminated beef if the vCJD diagnosis is confirmed. This has been the cause of most confirmed cases of vCJD in Britain.
It is believed the man never lived in Britain, and so if the diagnosis is confirmed, this would be the first case of vCJD, the human form of mad cow disease, to originate within the State.
The man, who is in his 20s, was still seriously ill last night. Neither he, nor the hospital which has been treating him for more than a week, are being named.
The hospital statement said the patient "has met some of the clinical diagnostic criteria for the disease and further diagnostic evaluation is ongoing.
"All of the necessary precautions are being taken and all of the appropriate authorities have been informed"
The hospital statement issued on Saturday added: "In the interests of patient confidentiality, no further information will be issued at this stage and we ask that the privacy of the patient and family be respected at this difficult time."
While news of the suspect case became public on Friday, the Tánaiste and Minister for Health, Ms Harney, has confirmed she was informed of the suspected case on October 14th.
"She immediately called a meeting with the chief medical officer and also met the chairman of the CJD Advisory Board the following day," her spokesman said.
Only one person, a woman who had lived in Britain, was previously diagnosed with the disease in the Republic.
A spokeswoman for the Food Safety Authority of Ireland said that because the incubation period for the disease was 10 to 15 years, people eating beef at the present time had no reason to be worried.
The spokeswoman said strict controls were in place since the BSE crisis to ensure meat entering the food chain could not be contaminated.
The chairman of the State's CJD Advisory Group, Prof Bill Hall, said there was no need for public alarm.
"The indication that there is a suspect case at the present time should not increase any public anxiety.
"There has been a number of risk assessments to estimate the number of cases we might expect to see in Ireland and this has shown that this would be between zero and one which is an extremely low number.
"At the worst case scenario this could be as high as 10 cases," he said.
The Department of Health said last night that Ms Harney had been assured "that every possible safeguard and preventative measure had been taken in relation to vCJD".