Page:Bergey's manual of determinative bacteriology.djvu/961

 tsutsugamushi disease by complement fixation, agglutination and precipitin tests, less readily from Rickettsia prowazekii by these tests. Possesses a common antigenic factor with Proteus OX$19$ 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 Rickettsia 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 infected 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 typhus (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 (Echidnophaga 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.

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

Organisms intracytoplasmic but not intranuclear. Transovarial transmission in trombiculid 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 type species of the subgenus is Rickettsia tsutsugamushi (Hayashi) Ogata.

3. Rickettsia tsutsugamushi (Hayashi, 1920) Ogata, 1931. (Theileria tsutsngamushi Hayashi, Jour. Parasit., 7, 1920,63; Rickettsia orientalis Nagayo, Tamiya, Mitamura and Sato, Jikken Igaku Zasshi, H, (May 20) 1930, 8 pp.; Rickettsia tsutsugamushi Ogata, Zent. f. Bakt., I Abt., 122, 1931, 249; Rickettsia akamushi Kawamura and Imagawa, Zent. f. Bakt., I Abt., 122, 1931,258; Rickettsia orientalis var. schiiffneri Franco do Amaral and Monteiro, Mem. Inst. Butantan, 7, 1932, 360; Rickettsia megawi Franco do Amaral and Monteiro, loc. cit.; Rickettsia megawai var. fletcheri Franco do Amaral and Monteiro, ibid., 361; Rickettsia tsutsiigamushi=orientalis Kawamura, Nisshin Igaku (Modern Medicine), 23, 1934, 909; Rickettsia pseudotyphi Vervoort, see Donatien and Lestoquard, Acta Conv. Tertii Trop. atque malariae morbis, pars I, 1938, 564; Rickettsia sumatranus (sic) Kouwenaar and Wolff, Proc. 6th Pacific Sci. Cong. (1939), 5, 1942,