Biological warfare is nothing new to the human race. Attempts to use disease to bring down enemies date as far back as we have detailed histories of warfare. Even when the mechanisms for the spread of disease were poorly understood, biological warfare was popular. Dropping cadavers into an enemy’s water supply was common. Some inventive Tartars even tried catapulting victims of bubonic plague over the walls of the city of Kaffa (modern day Feodesia) during a siege.
More recently, several European nations spread smallpox--inadvertently and otherwise--among Native Americans, and later attempted to use biological warfare to their advantage during the first World War. Only after World War I did the 1925 Geneva Protocol attempt to limit biological warfare, with mixed success.
In all this time however, every attempt at biological warfare has been essentially offensive. The idea has always been to incapacitate or kill the enemy. Except once, in Poland, during World War II, where a pair of quick-thinking doctors used a little-known organism to keep the Nazis at bay.
The microorganism is Proteus OX19. In most ways it’s an entirely ordinary little bacterium. Its one remarkable feature is that human antibodies for Proteus OX19 cross-react with the antibodies for Ricksettia – the bacterium responsible for the deadly disease typhus. Blood from a patient infected with Proteus Ox19 will give a false-positive in the most common typhus screening method, the Weil-Felix test.
Encouraged by this success, the good doctors went on to try their ruse on a larger scale. Germany was rightfully alarmed at the idea of typhus. An epidemic originating in a camp could easily spread into the general German population. So Nazi officials started requesting broader blood tests, and they sent a medical team into the “afflicted” areas of Poland – the towns of Rozvadow and Zbydniowie, and several surrounding villages.
While the Polish doctors could, and did, inject a number of other people with Proteus to induce positive Weil-Felix results, an on-site Nazi medical team could well have proved their undoing. Fortunately, ingenuity and a good dose of hospitality and alcohol prevented them from being uncovered. From the British Medical Journal:
With the medical team convinced, the Nazis left both towns and their surrounding villages alone, sparing them the ravages of the purges that killed a fifth of Poland's population by the end of the war. It was a tremendous triumph for the Polish doctors and, whether they realized it or not, their inventive tactic was unique in the annals of biological warfare.