The Health Protection Surveillance Centre was notified of the a case of leprosy in January of this year.
Irishhealth.com said that a South American man in the north-east of the country, who had been previously diagnosed, was suffering a resurgence of the disease.
It is the first time a case has been recorded in decades, however he did not contract it in Ireland.
Leprosy is not highly infectious - and is even curable if caught early.