Pneumonic Plague in Manchuria, 1910-1911
Whenever humans encroach on previously uninhabited (or sparsely inhabited) natural habitats, major disease outbreak is a typical result. One example is Lyme Disease in the United States (suburban sprawl + deer ticks). Another was the outbreak of pneumonic plague (the same bacteria that causes bubonic plague, but in a more deadly form that infects the lungs) in Manchuria in 1910-1911 (and again in 1921). The main reason was that the price of marmot furs had nearly quadrupled. A sort of "gold rush" to Manchuria to trap marmots ensued. The only problem was that this region, and its marmots, were a natural focus of plague (Yersinia pestis). In his classic study of disease in history, William H. McNeill explains some of the details:
Nomad tribesmen of the steppe region [parts of Manchuria, Mongolia, and Russia], where these animals lived, had mythic explanations to justify epidemiologically sound rules for dealing with the risk of bubonic infection from marmots. Trapping was taboo; a marmot could only be shot. An animal that moved sluggishly was untouchable, and if a marmot colony showed signs of sickness, custom required the human community to strike its tents and move away to avoid bad luck. Such customary prescriptions presumably reduced the possibility of human infection with plague to minor proportions.
But in 1911, as the Manchu [Qing] Dynasty tottered toward its final collapse, long-standing government regulations prohibiting the Chinese from moving into Manchuria broke down. As a result, swarms of inexpert Chinese emigrants went after marmot furs. Knowing nothing of local traditions, the Chinese trapped sick and healthy animals indiscriminately--with the result that plague spread out among them and then spread among the newly-constructed railroad lines of Manchuria from what speedily became its urban focal center at Harbin. (William H. McNeill, Plagues and Peoples [Anchor Books, 1977, 1989], pp. 137-138).

Above: plague victims in an open pit in Harbin, Manchuria, just before cremation. The basic procedure was to mix the bodies of dead people and animals with wood and douse everything with gasoline. Although done in the name of "hygiene," the main point of these macabre bonfires was for local officials to demonstrate that they were taking vigorous action to stop the spread of plague. While, the bonfires probably did no good beyond boosting the morale of survivors, strict quarantine measures, while brutal, did indeed restrict the scope of the epidemic.

One of the bonfires of death. In the foreground are gasoline cans.

Manchuria was in the Russian "sphere of influence" at this time. Here a Russian soldier arrests a suspected plague victim at sword point.

If this Russian doctor determines that this man is sick, he will enter this boxcar already crowded with victims (and possibly a few who just happened to be sick with something else--if so they'll soon have plague too). Both Qing officials and Russian officials were aggressive in applying modern, progressive public health measures to stem the epidemic.