Studies on Rocky Mountain spotted fever / U.S. Treasury Department, Public Health Service.

Date:
[1930]
Catalogue details

Licence: Public Domain Mark

Credit: Studies on Rocky Mountain spotted fever / U.S. Treasury Department, Public Health Service. Source: Wellcome Collection.

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    ing largely restricted to the reproductive organs they were usually distributed in large numbers throughout the tissues. | In the noninfected group the rickettsize stained, as a rule, purple or pink and were generally filiform organisms. However, in many instances they closely resembled, and to us were indistinguishable from the deep-blue staining, short bacillary and diplo-bacillary forms found in the infected group. In the muscle tissue of the infected group the rickettsiz were very numerous, stained blue, and frequently were arranged in rows packed between the muscle fibers (not intracellular). ; Of the 100 ticks from the east side of the Bitterroot Valley not one produced spotted fever when the viscera were injected into guinea pigs, nor were any of the animals subsequently immune to 1 ¢. c. of guinea pig’s blood virus. Of the infected group which is further analyzed in Table 20, 60 produced spotted fever and 5 (a total of 65 per cent) gave evidence of infection by immunizing the injected guinea pigs against a sub- sequent injection of blood virus. In some individual lots of this in- fected group more than 90 per cent gave evidence of infection, in others only 3314 per cent. TABLE 20.—Comparison of resulis of guinea pig inoculation of the viscera of 100 reared, infected adult ticks with the presence of rickettsie in the smears of same [1925 series] 100 REARED INFEOTED ADULT TICKS 40 ticks in which rickettsize could not be found 60 ticks with rickettsie in one or more organs Result of guinea-pig injection Result of guinea-pig injection Evidence of infec- No evidence of Evidence of infec- No evidence of tion infection tion | infection —_ Death Spotted Im- : rom Spotted Im- | : from . Negative| inter- a Negative] inter- fever munity current fever munity current infection infection 54 0 5 | I 6 5 27 2
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