BRATISLAVA — The eurozone has a long and productive future ahead of it, the head of the OECD said Thursday in the face of mounting concern for the bloc’s financial health. “The euro as a currency has a long life, it is alive, well and kicking and more countries will be joining in the future instead of leaving,” Organization for Economic Cooperation and Development (OECD) Secretary-General Angel Gurria told journalists in Bratislava. “The euro area is going to be growing and continue to be largest trading bloc in the world.” Earlier this week, the domestic media quoted Slovak Finance Minister Ivan Miklos as saying the eurozone was facing challenges and in the worst-case scenario a possible break-up. The 16-nation bloc, set to expand to embrace its newest member Estonia on Jan. 1, 2011, is being battered by a debt crisis that has forced Greece and Ireland to appeal for bailouts from the European Union and International Monetary Fund worth tens of billions of euros. With concern rising now that Portugal and Spain may be next in line for massive aid in the face of gaping public deficits, fears over market instability are spreading.