FAMILY I. RICKETTSL\CEAE 



939 



tsutsugamushi disease by complement 

 fixation, agglutination and precipitin tests, 

 less readily from Rickettsia prowazekii by 

 these tests. Possesses a common antigenic 

 factor with Proteus OX19 and a soluble 

 antigen in yolk-sac cultures. 



Lethal effect: Heavily infected yolk-sac 

 cultures injected intravenously or intra- 

 peritoneally are fatal to white mice in a few- 

 hours. Toxin neutralization test in white 

 mice is specific and distinct from that of 

 epidemic typhus toxin. 



Pathogenic for man, apes, monkeys, 

 rabbits, guinea pigs, white rats, eastern 

 cotton rat, white mice and gerbilles. Other 

 susceptible animals include the woodchuck, 

 house mouse, meadow mouse, white-footed 

 mouse, old-field mouse, cotton mouse, 

 golden mouse, wild rat (Rattus norvegicus), 

 wood rat, rice rat, flying squirrel, gray 

 squirrel, fox squirrel, gopher, cottontail 

 rabbit, swamp rabbit, chipmunk, skunk, 

 opossum and cat. Persists for at least a year 

 in rat brains in contradistinction to Rickett- 

 sia prowazekii and members of the subgenus 

 Dermacentroxenus. After intraperitoneal 



inoculation, a characteristic febrile reaction 

 occurs in the guinea pig with scrotal swelling 

 without necrosis. Passage in guinea pigs is 

 accomplished by transfer of tunica and 

 testicular washings or of blood from in- 

 fected animals. Cause of a febrile disease 

 with exanthema in man, producing low 

 mortality. 



Source: Observed by Wolbach and Todd 

 {op. cit., 1920, 158) in the endothelial cells 

 of the capillaries, arterioles and veins in 

 sections of skin from cases of Mexican ty- 

 phus (tabardillo). Also described by Mooser 

 in sections and smears of the proliferated 

 tunica vaginalis of guinea pigs reacting to 

 the virus of Mexican typhus. 



Habitat: Found in infected rat fleas 

 (Xenopsylla cheopis, X. astia, Nosopsylla 

 fasciatus), infected chicken fleas (Echidno- 

 phaga gallinacea) found on wild rats, and the 

 rat louse (Polyplax spinulosus). Will also 

 grow in human lice. Wild rats and field mice 

 act as the animal reservoir of infection. The 

 etiological agent of endemic (murine) 

 typhus which is transmitted to man by the 

 rat flea. 



Subgenus B. Zinsser a Macchiavello, 1947. 



(Macchiavello, Prim. Reunion Interamer. del Tifo, Mexico, 1947, 416; Trombidoxenus 



Zhdanov and Korenblit, Jour. Microbiol., Epidemiol, and Immunobiol. 



(Russian), No. 9, 1950, 42.) 



Zins'se.ra. M.L. noun Zinssera named for Hans Zinsser, who studied rickettsial agents. 



Organisms intracytoplasmic but not intranuclear. Transovarial transmission in trombi- 

 culid mite vectors, only the larvae of which are parasitic on vertebrates. Disease in man 

 elicits OXK Weil-Felix serological reactions and is accompanied by adenitis and often by 

 an eschar at point of mite bite. 



The tj'pe species of the subgenus is Rickettsia tsutsugamushi (Hayashi) Ogata. 



3. Rickettsia tsutsugamushi (Hayashi, 

 1920) Ogata, 1931.* {Theileria tsutsngamushi 

 Hayashi, Jour. Parasit., 7, 1920,63; Rickett- 

 sia orientalis Nagayo, Tamiya, Mitamura 

 and Sato, Jikken Igaku Zasshi, H, (May 20) 

 1930, 8 pp.; Rickettsia tsutsugamushi Ogata, 

 Zent. f. Bakt., I Abt., 122, IQZl, 2^9; Rickett- 

 sia akamushi Kawamura and Imagawa, 

 Zent. f. Bakt., I Abt., 122, 1931,258; Rickett- 

 sia orientalis var. schiiffneri Franco do Ama- 

 ral and Monteiro, Mem. Inst. Butantan, 7 , 



1932, 360; Rickettsia rnegawi Franco do 

 Amaral and Monteiro, loc. cit.; Rickettsia 

 megawai var. fletcheri Franco do Amaral and 

 Monteiro, ibid., 361 ; Rickettsia tsutsiigamushi= 

 orientalis Kawamura, Nisshin Igaku (Mod- 

 ern Medicine), 23, 1934, 909; Rickettsia 

 pseudotyphi Vervoort, see Donatien and 

 Lestoquard, Acta Conv. Tertii Trop. atque 

 malariae morbis, pars I, 1938, 5M; Rickettsia 

 sumatranus (sic) Kouwenaar and Wolff, 

 Proc. 6th Pacific Sci. Cong. (1939), 5, 1942, 



* The reasons for transferring Hayashi's species from the genus Theileria to Rickettsia 

 and other questions of nomenclatorial priority in regard to this species are discussed in 

 Manual, 6th ed., 1948, 1089 and 1090 (footnotes). 



