The Health Service Executive has said that the diagnosis of the first case of the Zika virus in Ireland is not unexpected, as many other European countries have reported infections.
The HSE says the two unrelated cases involved a man and a woman who had travelled to a Zika-affected country in the first four to five months.
Both have recovered.
Speaking on RTÉ's Morning Ireland the Assistant National Director of Health Protection at the HSE said both adults returned to Ireland with a mild illness but there was no initial suspicion that it was Zika until people became more aware.
Dr Kevin Kelleher said 75-80% of people do not know they have it and that it is like a very mild cold or flu type illness.
Dr Kelleher, said the reason it has become a major potential problem is not the disease itself but the effect it appears to have on the unborn baby if the pregnant mother gets it.
He said they have become aware of this because it has moved from Africa and South East Asia to the South Americas where a large number of people have never been exposed to it.
He said the likelihood is that no-one needs hospital treatment as a consequence of this disease.
He urged women who are pregnant or who want to get pregnant to decide if their need to travel to these areas is essential.