1260 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



guinea pig tissues immunize the guinea 

 pig but vaccines made from mouse tissues 

 do not. Mice immune to this virus are 

 susceptible to infection with pseudo- 

 lymphocytic choriomeningitis virus and 

 vice versa. 



Thermal inactivation : At 55 to. 56° (J 

 in 20 minutes. 



Filterability : Passes Berkefeld V, X, 

 and W filters and, with difficulty, a Seitz 

 asbestos pad.- 



Other properties : Infective at least 206 

 days in storage at 4 to 10° C in 50 per cent 

 neutral glycerine in 0.85 per cent saline. 

 Infective particle calculated to be 37 to 

 55 millimicrons in diameter on the basis 

 of centrifugation studies; 40 to 60 milli- 

 microns by ultrafiltration tests. Inac- 

 tivated by soap with loss of mouse-im- 

 munizing capacity. 



Literature : Armstrong and Dickens, U. 

 S. Pub. Health Service, Public Health 

 Rept., 60, 1935, 831-842; Armstrong and 

 Lillie, ibid., Jfi, 1934, 1019-1027; Arm- 

 strong and Wooley, ihid., 50, 1935, 537- 

 541; Jour. Am. Med. Assoc, 109, 1937, 

 410-412; Baird and Rivers, Am. Jour. 

 Pub. Health, 28, 1938, 47-53; Casals- 

 Ariet and Webster, Jour. Exp. Med., 7/, 

 1940, 147-154; Dalldorf, ibid.. 70, 1939, 

 19-27; Dalldorf and Douglass, Proc. Soc. 

 Exp. Biol, and Med., 39, 1938, 294-297; 

 Findlay and Stern, Jour. Path, and Bact ., 

 48, 1936, 327-3.38; Findlay et al.. Lancet, 

 230, 1936 (/), 650-654; Howard, Jour. 

 Inf. Dis., 64, 1939, 66-77; Laigret and 

 Durand, Compt. rend. Acad. Sci., 203, 

 1936, 282-284; Lepine and Sautter, Ann. 

 Inst. Pasteur, 61, 1938, 519-526; Lepine 

 et al., ibid., 204, 1937, 1846-1848; Mac- 

 Callum and Findlay, Brit. Jour. Exp. 

 Path., 21, 1940, 110-116; Milzer, Jour. 

 Inf. Dis., 70, 1942, 152-172; Rivers aiid 

 Scott, Jour. Exp. Med., 63, 1936, 415-432 ; 

 Scott and Elford, Brit. Jour. Exp. Path., 

 20, 1939, 182-188; Scott and Rivers, Jour. 

 Exp. Med., 63, 1936, 397-414; Shaugnessy 

 and Zichis, ibid., 72, 1940, 331-343; 

 Smadel and Wall, ibid., 72, 1940, 389-405 ; 

 75, 1942, 581-591; Smadel et al., Proc. 

 Soc. Exp. Biol, and Med., 40, 1939, 71-73; 



Jour. Exp. Med., 70, 1939, 53-66; 7^ 1940, 

 43-53; Stock and Francis, ibid., 77, 1943, 

 323-336; Traub, Science, 81, 1935, 298- 

 299; Jour. Exp. Med., 63, 1936, 533-546, 

 847-861; 64, 1936, 183-200; 66, 1937, 317- 

 324; 68, 1938, 9.5-110, 229-250; 69, 1939, 

 801-817. 



3. Legio simulans spec. nov. From 

 Latin simulare, to imitate, in reference to 

 resemblance of this virus to the preceding 

 in many respects, though not in size or 

 antigenic properties. 



Common name : Pseudo-lymphocytic 

 choriomeningitis virus. 



Hosts : HOMINIDAE — Ho7no sapiens 

 L., man. Experimentally, also mouse, 

 guinea pig, rhesus monkey; chorioallan- 

 toic membrane of chick embryo. 



Induced disease : In man, benign asep- 

 tic lymphocj'tic meningitis with virus 

 in cerebro-spinal fluid; severe frontal 

 headache, drowsiness, irritability, vomit- 

 ing, eventual complete recovery. In 

 mouse, experimentally, roughened fur, 

 spontaneous tremor, hunched attitude, 

 irritability, clonic movements ending 

 with tonic convulsions on stimulation, 

 temporary recovery from spasm with 

 survival a few hours or instant death. 



Serological relationships : Hyperim- 

 mune sera for lymphocytic choriomenin- 

 gitis virus are ineffective for this virus, 

 and vice versa. In man, after recovery, 

 neutralizingantibody is strong at 1 month, 

 fading before 7 months. 



Immunological relationships: Mice ac- 

 (juire specific resistance to reinfection 

 after experimental disease ; mice immune 

 to lymphocytic choriomeningitis virus are 

 susceptible to pseudo-lymphocytic chori- 

 omeningitis virus and vice versa. 



Thermal inactivation : At 56° C, not at 

 45° C, in 30 minutes. 



Filterability : Passes Berkefeld V, not 

 N, filter candle; Gradacol membrane of 

 320, not 300, millimicron average pore 

 diameter. 



Other properties : Particle diameter 

 calculated to be not above 150 to 225 

 millimicrons, from filtration experiments. 



