Disease/Infection because things like penicillin weren't made until WW2
In connections academy there is a textbook it should explain everything in the book
Argentina, Belgium, Bolivia, Brazil, British Empire, Chile, Republic of China, Colombia, <span><span /><span><span><span> United Kingdom,</span><span> Australia,</span><span> Canada</span><span>, India,</span><span> New Zealand</span><span>, South Africa</span></span>,
</span><span /><span /><span> Cuba</span><span>, Czechoslovakia, Germany,</span><span> Denmark</span><span>, El Salvador, </span><span>France, </span><span>Greece</span><span>, Guatemala,</span><span>Haiti,</span><span> Honduras,</span><span> Kingdom of Italy, </span><span> Empire of Japan, </span><span> Liberia,</span><span> Netherlands,</span><span> Nicaragua,</span><span> Norway,</span><span> Panama,</span><span> Paraguay, </span><span> Persia,</span><span> Peru,</span><span> Poland,</span><span> Portugal</span><span>, Romania, </span><span> Siam aka Thailand, </span><span> Spain,</span><span> Sweden,</span><span> Switzerland,</span><span> Uruguay</span><span>, Venezuela,</span></span><span><span> Austria,</span><span> Bulgaria, </span><span>Costa Rica, </span><span> Finland, </span><span> Luxembourg,</span><span> Albania, </span></span>
