Status of Murine Typhus Infection in Domestic Rats in the United States, 1952, and Relation to Infestation by Oriental Rat Fleas

Murine Typhus: An Unrecognized Suburban Vectorborne Disease

“…An aggressive campaign initiated by the US Public Health Service in 1945 to control rats and their fleas effectively reduced typhus reports to !100 cases per year by the late 1980s [3][4][5][6][7]10]. Since 1980, case reports have receded to the southern regions of Texas and California where the opossum maintains the life cycle [3,4].…”

“…Fleaborne diseases, such as epidemic and endemic (murine) typhus, which had previously been common in highdensity urban human and rodent populations, have nearly been eliminated in the United States [3][4][5][6][7]. However, murine typhus continues to be documented in suburban settings, where opossums, cats, and their fleas coexist [8][9][10][11].…”

Epidemiology of Murine Typhus

“…The majority of cases occurred during late spring and early autumn, when X. cheopis was very abundant (20--22, 40). Moreover, a marked decline in cases of murine typhus in the US was reported after X. cheopis populations were effectively brought under control by sustained DDT dusting campaigns (43,44,52). Although the association between X. cheopis and Rattus and their presence in human habitations shows a strong correlation with reported cases of murine typhus, the disease has also been reported in areas where either the flea or rat was absent.…”

History, Rats, Fleas, and Opossums: The Ascendency of Flea-Borne Typhus in the United States, 1910–1944

“…Above 33° north latitude (roughly the border between LA and AK), most cases occurred in workers of food establishments in business districts of urban centers [133,146,182]. Flea-borne typhus was most prevalent in areas where the average January temperature was above 4 °C and the average relative humidity in July at noon was above 37% [183]; these conditions are favorable for rat flea proliferation [34]. Seasonally, the lowest number of FBT cases was reported in the fall and winter and the greatest in July through During World War II, imports of various rodenticides to the United States were terminated [174,175].…”