-after Russo-Chinese War (1893-9) troops on both sides have bubonic plague
-in China it already exists so outbreak is somewhat mitigated
-but in Russia it's positively disastrous as troops come from everywhere
-as such in Europe and Americas the bubonic plague becomes nicknamed the "Russian plague"
-as troops have brought it with them
-additionally Pacific diaspora brings it with them which causes a smaller outbreak in Australasia