Kildare, Dublin and Wicklow accounted for 79 per cent of cases
Health officials are warning of a national outbreak of syphilis, and it is particularly prevalent in Kildare.
The Health Protection Surveillance Centre says while there was a decrease during the first lockdown 242 cases were reported in the first four months of this year.
There are concerns that there may be 'a large reservoir' of undiagnosed cases as many STI services have been operating at a reduced level due to the Covid-19 pandemic.
Untreated syphilis can cause serious health problems to the heart, brain, eyes and nervous system.
Kildare, Dublin and Wicklow accounted for 79 per cent of cases, followed by 9 per cent in Cork and Kerry.
91 per cent were in men and 9 per cent were in women.