A national outbreak of the sexually transmitted infection syphilis has been declared.
Health officials are warning 'a large reservoir' of cases may be undiagnosed, due to the COVID-19 pandemic.
Untreated syphilis can cause serious health problems to the heart, brain, eyes and nervous system.
The Health Protection Surveillance Centre says early infectious syphilis (EIF) cases were rising here before the COVID-19 crisis.
There was a small decrease last year, coinciding with the first wave of the pandemic.
However, the HPSC says cases are increasing again and are, in fact, exceeding the numbers seen before the COVID-19 crisis.
242 cases were reported in the first four months of this year.
Dublin, Kildare and Wicklow accounted for 79% of cases, followed by 9% in Cork and Kerry.
91% were in males and 9% were in females.
The HPSC says there is also a potentially large undiagnosed reservoir of syphilis infections, as many STI services have been operating at a reduced level due to the Covid-19 pandemic.
The HSE cyber attack has also impacted health officials' ability to monitor cases.
Officials say safer sex practices, as well as regular testing among at risk groups, are vital to prevent cases of the infection.
The Health Minister says STI services are operating, and people should "absolutely seek a diagnosis or treatment" if they have any concerns.
He stressed that syphilis is treatable, but the infection can cause serious problems if left untreated.
