Independent Senator David Norris who unsuccessfully stood for Ireland’s presidency in 2011 says he is undergoing treatment for cancer.
In a statement on Wednesday, Mr Norris said was he had been undergoing medical treatment in Dublin.
“The cancer appears to be related to the initial incidence of viral hepatitis which I contracted from tainted drinking water while I was on unpaid government business in Eastern Europe in 1994,” Senator Norris said.
He said he continued to enjoy life and hoped to return to his duties in the Irish Seanad in the next few days.
Mr Norris, a leading James Joyce scholar, was the first openly gay candidate for the presidency of Ireland.
It followed revelations that he had written to an Israeli court pleading for clemency for his former partner Ezra Yizhak.
Yizhak had been accused of the statutory rape of a 15-year-old Palestinian boy in 1992. He admitted the charge, pleading guilty and was convicted in 1997.
At that time, Mr Norris said he had written the letter “out of love and concern”.
Speaking last month the senator revealed he had suffered from serious depression and had a complete collapse after the election campaign.
The James Joyce scholar said “the volume of sheer lies” that had been told about him during the campaign had a serious effect on his health.
He said his doctor told him that he had a “major depression” and had suffered a nervous breakdown.