Uniforms worn while researching plague bacteria.
These plague researchers were working with the bacillus in the Philippines in 1912. The Third Pandemic was the last major pandemic of plague, which began in Yunnan Province in China, in 1855. It was considered an active pandemic by the World Health Organization until 1959, when cases dropped below 200/year.
Unlike the Black Death, which is believed to have been at least equal parts pneumonic plague and bubonic plague (though pneumonic contributed to more deaths), the Third Pandemic was mostly bubonic plague (far less deadly, though still dangerous and highly virulent). Despite this, it still contributed to over 12 million deaths in China and India alone, and spread to all inhabited continents.