A rat was captured at the corner of Florida Walk and Music Street in New Orleans as part of the continuing federal campaign against bubonic plague. Nearly a month later, on September 18, laboratory examination established that the animal was infected with plague. The finding appeared in the October 6, 1916, issue of Public Health Reports, where the United States Public Health Service recorded the capture and confirmation as part of its national disease-surveillance system. Although the discovery involved a single rodent rather than a human patient, it carried substantial historical significance. It demonstrated that Yersinia pestis remained present within New Orleans's rat population more than two years after the city's first recognized human cases and showed why public-health officials continued intensive surveillance even after the immediate epidemic had subsided.
Bubonic plague had emerged publicly in New Orleans in June 1914. Federal records reported the first recognized case on June 27, involving a 49-year-old man who subsequently died. A second case soon followed. Louisiana and New Orleans authorities requested assistance from the United States Public Health Service, which assumed a major role in the suppression campaign. By this period, medical investigators understood that plague circulated among rodents and could be transmitted through infected fleas. The response therefore differed sharply from older quarantine strategies that concentrated primarily on sick people. Public-health officials attacked the animal reservoir, the urban environment that sustained it, and the routes by which rats moved between buildings, docks, ships, warehouses, and neighborhoods.
New Orleans presented serious difficulties for plague control. As one of the nation's most important ports, the city contained extensive wharves, warehouses, food-storage facilities, markets, shipping traffic, wooden buildings, crawl spaces, and other environments capable of supporting large rodent populations. Federal and local authorities established trapping operations on a massive scale. Captured rats were labeled according to the precise location where they had been taken and transported to laboratories for examination. Public Health Service accounts indicate that during intensive periods thousands of rats could be collected daily. From 1914 through 1915, federal operations resulted in the destruction of more than half a million rats.
Officials also sought permanent environmental changes. New Orleans adopted ordinances requiring rat-proofing measures in buildings. Wooden floors and other vulnerable spaces could be replaced or protected with concrete or wire barriers. Structures could be elevated to reduce rodent harborage. Garbage storage received greater regulation. Wharves and commercial properties were subjected to sanitation requirements, while vessels were inspected, trapped, fumigated, and required to employ measures intended to prevent rats from moving between ships and shore. These policies transformed plague control into a program of municipal sanitation, building regulation, laboratory testing, maritime health enforcement, and continuous epidemiological surveillance.
The August 21, 1916, rat is important because it illustrates the persistence of infection after human plague had largely disappeared. Historical accounts record thirty human plague cases in New Orleans during 1914 and only one during 1915. The absence of continuing human cases did not establish that the underlying source had vanished. The infected rat captured at Florida Walk and Music Street supplied direct biological evidence that plague remained within the city's rodent population. Public-health officials therefore had a measurable reason to continue rat trapping, laboratory testing, sanitation enforcement, and structural rat-proofing rather than declaring victory solely because hospitals were no longer receiving plague patients.
The episode also demonstrates the development of modern disease surveillance. The rat's capture location and date were documented, the specimen was examined scientifically, and its infection was formally confirmed and reported. The National Library of Medicine preserves records of 353 cases of rodent plague in New Orleans between July 1914 and April 1917, with entries recording addresses, capture dates, confirmation dates, and descriptions of the premises involved. Such records allowed investigators to map the persistence and movement of infection at the neighborhood level.
New Orleans was eventually declared a clean port in April 1918 after prolonged antiplague operations produced no human or rodent cases. Plague reappeared in the city in 1919, however, requiring another major response and demonstrating the continuing danger posed by hidden animal reservoirs. The August 21, 1916, discovery therefore represents more than an unusual incident involving an infected rat. It documents a stage in the transition from emergency epidemic response to sustained scientific surveillance. Through trapping, laboratory diagnosis, sanitation, construction standards, and cooperation among municipal, state, and federal authorities, New Orleans became an important American case study in controlling an urban zoonotic disease by confronting its environmental and animal sources.
References / More Knowledge:
United States Public Health Service. “Louisiana—Plague Rats Found.” Public Health Reports, Vol. 31, No. 40, October 6, 1916. Centers for Disease Control and Prevention, Public Health Publications.
https://stacks.cdc.gov/view/cdc/67675/cdc_67675_DS1.pdf
United States Public Health Service. “Plague Reported in New Orleans.” Public Health Reports, Vol. 29, No. 27, July 3, 1914.
https://www.jstor.org/stable/4570972
United States Public Health Service. “Rat Proofing the Public Docks of New Orleans: A Report on Its Possibility and Cost.” Public Health Reports, Vol. 30, No. 8, February 19, 1915.
https://www.jstor.org/stable/4571956
National Library of Medicine. “Images from the History of the Public Health Service: Fighting the Spread of Epidemic Diseases.” U.S. National Library of Medicine.
https://www.nlm.nih.gov/exhibition/phs_history/fighting.html
National Library of Medicine. “Images from the History of the Public Health Service: Notable Contributions to Biomedical Research.” U.S. National Library of Medicine.
https://www.nlm.nih.gov/exhibition/phs_history/contributions.html
National Library of Medicine. “Plague Cases in New Orleans.” Archives and Modern Manuscripts Collection, MS C 109.
https://findingaids.nlm.nih.gov/subjects/1944
The Historic New Orleans Collection. “The Summer When Rats Brought the Black Death to New Orleans.”
https://hnoc.org/publishing/first-draft/summer-when-rats-brought-black-death-new-orleans
Louisiana Department of Health, Office of Public Health. “Plague Annual Report.” Infectious Disease Epidemiology Section.
https://ldh.la.gov/assets/oph/Center-PHCH/Center-CH/infectious-epi/Annuals/2021/Plague_LaIDAnnual_2021.pdf