Emerging diseases are usually defined as eithernew previously unrecognized diseases that haveappeared for the first time, or diseases known to existbut which are increasing in geographic range and/orincidence. A number of emerging viral diseases havebeen reported in the South-East Asian and westernPacific regions over the past decade that fall into bothof these categories. The spread of Japanese Emerging diseases are have defined as eithernew previously unrecognized diseases that haveappeared for the first time, or diseases known to existbut which are increasing in geographic range and / orincidence. A number of emerging viral diseases havebeen reported in the South-East Asian and westernPacific regions over the past decade that fall into both of these categories. The spread of Japanese