Mapping the plague in San Francisco’s Chinatown

Guest post by Guenter B. Risse

Maps and statistical charts are essential aids for demonstrating the location and frequency of epidemic disease around the world. Spotting the presence of diseases has a long tradition, stretching back at least to the seventeenth century. In fact, during a plague outbreak in Naples and Bari in the 1690s, mapmaking not only revealed the presence of this scourge but also the location of quarantine lines. From the 1820s onwards, “topographies of disease” identified sites of reported cases. “Dot maps” were used extensively to detect epidemic diffusion and establish possible causalities during epidemics of cholera, typhoid and yellow fever.

When plague was confirmed in March 1900, local and federal health officials in San Francisco created lists of plague deaths, routinely including name, age, and sex, as well as place and date of death. A Chinatown address became an important bit of information: although many sufferers had been hidden, moved around, and left to die elsewhere, the official plague lists revealed that the outbreak was concentrated in Chinatown. Sanitary inspectors routinely quarantined entire buildings in the neighborhood, planting warning flags and sending disinfection teams to cleanse the premises. As the death toll mounted, a Federal Commission of experts visited San Francisco in February 1901, confirming the presence of plague in the Chinese district.

Experts issued their first Chinatown map populated with circles for local Health Board cases and crosses for their own discoveries. In subsequent charts, each circle carried the official number issued to every case since the onset of plague. Given the lack of cooperation from the Chinese population, the maps helped sanitarians to bring into focus the most rat-infested areas of the district, especially those around Pacific Street and its theaters. Contemporaries were largely unaware that rat fleas transmitted plague, but they believed in the role of wild and domestic rodents in the transmission to humans. Although science was imperfect and the hostile behavior of the Chinese population may have led to a significant underreporting of cases, the charts marking individual plague deaths remained quite useful. They later guided planned demolitions of decrepit, rat-infested buildings during sanitary campaigns. All dotted maps were published in yearly Reports of the Surgeon General. The last was issued in 1905, after the plague outbreak had ended.

Based on mortality information supplied by the San Francisco Board of Health and the U.S. Marine Hospital Service, the current colored and interactive map, supplemented by summarized case reporting, reconstructs the spatial and temporal evolution of plague in San Francisco’s Chinatown during the 1900-1904 period. Together, the map and case reports provide vital information for understanding the successive contours of this notable American epidemic outbreak, and contributed to its successful eradication.

The map below was created by Elle Pfeffer and Zoe Ovans. It shows present-day San Francisco with the recorded deaths from the 1900-1904 plague epidemic overlaid. Click each point for information on the respective victim.