During WWII, Dr. Eugene Lazowski tricked the Germans by creating a fake epidemic in Poland. He knew of a bacterial strain that caused people to test positive for typhus with no ill effects- so he began injecting the strain into non-Jews. The Nazis assumed there was an outbreak, stayed away, and quarantined an area of about 8,000 people- which saved the lives of countless Jews and Poles who would have been killed or sent to camps. Source Source 2 Source 3