Human Plague in the United States 1900-1966

Epidemiology of Human Plague in the United States, 1900–2012

“…on the outskirts of the city by 1908 ( 3 ). In contrast, Y. pestis apparently never successfully established in wild rodent populations outside of Gulf coast port cities, likely a result of inhospitable ecology and early and extensive urban rat control efforts ( 3 , 5 , 8 ). …”

“…The first documented autochthonous human infection occurred in the Chinatown section of San Francisco, California, in March of 1900. Cases were soon reported in other port cities, including New Orleans, Galveston, Seattle, and Los Angeles ( 3 , 5 ). Along the Pacific Coast, infection spread from urban rats to native rodent species, and by the 1950s, Y. pestis had spread eastward to reach western portions of the Dakotas, Nebraska, Kansas, Oklahoma, and Texas.…”

“…Along the Pacific Coast, infection spread from urban rats to native rodent species, and by the 1950s, Y. pestis had spread eastward to reach western portions of the Dakotas, Nebraska, Kansas, Oklahoma, and Texas. This distribution has remained static for >60 years, presumably the result of climatic and ecologic factors that limit further spread ( 3 , 5 – 9 ). Although poorly defined, these factors may be related to the ecology of vector species rather than that of rodent hosts ( 8 ).…”

Initiation and Spread of Traveling Waves of Plague, Yersinia Pestis, in the Western United States

“…Similarly, incoming ships in New York in 1899 reportedly carried human plague cases. 25,34 However, available historical records indicate that plague did not become established in these or the surrounding areas. These apparently failed invasions could be due to stochastically driven chance events, which can have a significant influence over the outcome of an invasion when only a small number of diseased individuals exists.…”

“…Although its presence was acknowledged in Chinatown, and a quarantine was imposed, non-Chinese businesses present within the controlled area were exempt from these restrictions. 34 These actions likely facilitated the invasion and eventual establishment of plague into the continental United States, which provided ample time for the disease to spread through the urban rodent communities and into the surrounding wildlife populations.…”