to the genera Amblyomma, Dermacentor, Rhipicephalus, Ornithodoros and Haema- phjsnlis have been experimentally infected. The agent is transmissible through tick ova. The etiological agent of Rocky Mountain spotted fever, Sao Paulo exanthematic t5'phus of Brazil, Tobia fever of Colombia and spotted fevers of Minas Gerais and Mexico, which are all transmitted to man by the bite of infected ticks. Gould and Miesse (Proc. Soc. Exp. Biol, and Med., 85, 1954, 558) reported the first isolation in the U. S. A. of identified infection in a Microtus field mouse. 5. Rickettsia conorii Brumpt, 1932. {Rickettsia conori (sic) Brumpt, Compt. rend. Soc. Biol., Paris, 110, 1932, 1199; Rickettsia megaioi var. pijperi Franco do Amaral and Monteiro, Mem. Inst. Butan- tan, 7, 1932, 361; Rickettsia bland Cami- nopetros, l""' Cong. Internat. Hyg. Med- iterr., Rapports et Compt. rend., 2, 1932, 202; Dermacentroxenus rickettsi var. pijperi Mason and Alexander, Onderst. Jour. Vet. Sci. and Anim. Ind., 13, 1939, 74; Derma- centroxenus rickettsi var. conori Mason and Alexander, loc. cit.; Rickettsia {Dermacen- troxenus) conori Philip, Amer. Jour. Hyg., 37, 1943, 307; Dermacentroxenvs conori Steinhaus, Insect Microbiology, 1946, 339; Dermacentroxemis pijperi Macchiavello, Prim. Reunion Interamer. del Tifo, Mexico, 1947, 414; Ixodoxenus conori Zhdanov, Opredelitel Virusov Celovska i Zivotmych, Izd. Akad. Med. Nauk, U.S.S.R., Moskau, 1953, 52 and 157.) co.no'ri.i. M.L. gen.noun conorii of Conor; named for A. Conor, the first to describe adequately boutonneuse fever. Resembles Rickettsia rickettsii. In the tick, diplococcoid and diplobacillary forms pre- dominate, though they are smaller and more coccoid when they occur in compact masses. In tissue cultures the organisms are lanceo- late, diplococcoid and diplobacillary, oc- curring in the nuclei as well as in the cyto- plasm of the cells. 0.3 to 0.4 by 1.0 to 1.75 microns. Non-motile. Stain purplish with Giemsa's stain, blue with Castaneda's stain and bright red with a blue background with Macchiavello's stain. Gram-negative. Cultivation: May be cultivated in plasma tissue culture of mammalian cells, in modi- fied Maitland media and in the yolk sacs of chick embryos. Weyer (Acta Tropica, 11, 1954, 194) found differences in growth of Kenya and South African strains compared to a classic strain from the Mediterranean area. Immunology: The disease is related im- munologically to Rocky Mountain spotted fever with which it cross immunizes, but spotted-fever vaccine does not protect against the Mediterranean, Asiatic and South African strains of boutonneuse fever. Attempts to produce potent vaccines either from tick or culture sources have so far been ineffective. Serology: Cross fixation occurs with R. rickettsii by complement-fixation test. Possesses a common antigenic factor with Proteus 0Xi9 and OX2 but not with OXK. Pathogenic for man and guinea pigs. Also pathogenic in var3qng degrees for dogs, horses, spermophiles, monkeys, rabbits, gerbilles and white mice. Boutonneuse fever is a much less virulent infection for the guinea pig than is Rocky Mountain spotted fever. A temperature reaction, ac- companied by scrotal swelling, occurs but there is no sloughing. There is practically no mortality. Passsage in guinea pigs is ac- complished most effectively by transfer of testicular washings. In man there occur localized primary sores (taches noires) at the site of the tick bite and inflammatory reactions in the regional lymph nodes. A febrile reaction with exanthema occurs, and mortality is low. Source: Observed by Caminopetros (Compt. rend. Soc. Biol., Paris, 110, 1932, 344) in smears from the tunica vaginalis of guinea pigs inoculated with infected dog ticks (Rhipicephalus sanguineus). Habitat: Found in the brown-dog tick (Rhipicephalus sanguineus) and also in the ticks Amblyomma hebraeiim, Haemaphysalis leachii, Rhipicephalus appendiculatus , R. evertsi and Boophilus decoloratus. Trans- missible through the ova of ticks to follow- ing generations. The probable animal reser- voir is the dog in the Mediterranean area and, in addition, perhaps veld rodents in South Africa. The etiological agent of boutonneuse fever in man (also known as
