Recent Developments in Murine Typhus Fever Control

Abstract

MURINE, or rat-borne, typhus fever in the United States increased steadily from 1913, when the first case was reported in Georgia, to 1940. During 1940 the reported cases dropped nearly a thousand to 1,845, but during the next four years increases of about a thousand cases a year were recorded -(Figure 1). In 1944, more than 5,300 cases were officially reported to state health departments. The total reported cases for 1945 is 5,167, which represents the first decrease since 1940. Since reporting has been far from complete, it is believed that the 5,167 cases reported in 1945 may represent about 25,000 actual cases of murine typhus fever.Although typhus has been reported from 3 7 states and the District of Columbia during the last five years, over 67 per cent of the cases have been confined to 100 counties in nine southern and southeastern states (Figure 2). These counties, however, have an annual incidence of 10 or more cases per year for the last five years and in one is greater than 100 cases per year. Annual morbidity rates ranged up to more than 430 per 100,000.1In the North, typhus can be almost universally traced to very small areas of the business sections of towns or cities, and usually it will be found that cases were contracted in one or more food handling establishments. There is * Presented before the Engineering Section, Southern

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

“…Although by 1946, typhus was reported in 37 states and the District of Columbia, 67% of cases occurred in just 100 counties in nine Southern states (NC, SC, GA, AL, FL, MS, LA, TX, and TN); the highest rates per county were 430 per 100,000 population. In the highest incidence areas (southwest GA, southeast AL, multiple TX foci), about half of the cases were contracted in rural and residential settings [182]. Furthermore, despite these high numbers, the actual incidence of FBT was thought to be much higher than the reported incidence because many cases were not brought to medical attention or because it was mistaken for other infections [31,146].…”

“…A progressively greater incidence of FBT was reported more southerly within this zone [133]. 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].…”

“…In FL, a serosurvey of FBT conducted in 1944-1946 concluded that cases in children and African Americans were under recognized [186]. Overall, it was thought that the number of cases of FBT nationwide was underestimated by 3-to 5-fold [146,180,182].…”

History, Rats, Fleas, and Opossums. II. The Decline and Resurgence of Flea-Borne Typhus in the United States, 1945–2019

“…While these compounds were effective rodenticides, some of these (e.g., zinc phosphide, 1080, and thallium sulfate) were so highly toxic that their use was restricted to trained personnel [ 51 , 55 ]. In terms of dead rodent recovery, Compound 1080 was ten-times more effective than any other rodenticide available in 1945–1946 [ 56 ], but it was so toxic that owners of the treated premises had to sign a release form absolving health authorities of responsibility in the event of an accidental poisoning [ 57 ]. Compound 1080 was manufactured with the addition of the dye Nigrosine so that an aqueous solution was an unappetizing black color to discourage accidental ingestion.…”

“…There were 20 rat-proofing projects underway on 1 July 1945, which quickly expanded to 101 typhus control projects by 15 October 1945, 56 of which used DDT dusting alone and 45 using DDT dusting and rat control. By 1946, the number of USPHS personnel employed in typhus control had grown from 60 to 400 [ 56 ]; these workers received the epidemic typhus vaccine, which may have been cross-protective against FBT [ 58 ]. Additionally, on 1 July 1946, the Communicable Disease Center (CDC; later to become the Centers for Disease Control) of the USPHS was established [ 59 ].…”