FAMILY ERRONACEAE 



1261 



Viable at least 1 month at 4° C, at least 

 1 year in 50 per cent glycerine, 40 da3^s in 

 0.25 per cent phenol, 1 year when dried 

 from frozen material. Inactivated by 

 0.05 per cent formalin at 4° C in 48 hours ; 

 by boiling in 5 minutes. 



Literature: MacCallum et al., Brit. 

 Jour. Exp. Path., 20, 1939, 260-269. 



4. Legio muris spec. nov. From Latin 

 mus, mouse. 



Common names : Mouse-poliomyelitis 

 virus, Theiler's-disease virus. 



Host : MURIDAE — Mus miisculus L., 

 white mouse. 



Insusceptible species : CERCO- 

 PITHECIDAE—Macaca mulatta (Zim- 

 mermann), rhesus monke3^ 



Geographical distribution : United 

 States, Japan, Germany, Palestine ; prob- 

 ably widespread wherever white mice are 

 raised. 



Induced disease : In white mouse, 

 ordinarily no obvious disease, virus oc- 

 curring in feces and not being recoverable 

 from thoracic or abdominal viscera or 

 head (probable source is in abdominal 

 wall ; virus has been recovered most 

 abundantly from intestinal contents, in 

 moderate amounts from walls of intestine 

 and in smaller concentration from mesen- 

 teric lymph glands) ; occasionally, in- 

 dividual mice show flaccid paralysis of 

 hind legs, and brain or spinal-cord sus- 

 pensions from these contain the virus ; 

 mice inoculated intracerebrally show 

 flaccid paralysis in 7 to more than 30 days, 

 first in one limb, later usually in all ; the 

 tail does not become paralyzed; very 

 ■young inoculated mice maj' die without 

 first showing paralysis ; very old inocu- 

 lated mice may become infected without 

 showing obvious disease ; some affected 

 mice recover and those showing residual 

 paralysis may become carriers of virus. 

 In affected, experimentally inoculated 

 mice, acute necrosis of ganglion cells of 

 anterior horn of spinal cord ; necrosis also 

 of isolated ganglion cells of cerebrum. 

 Later, marked neuronophagia. Perivas- 

 cular infiltration in brain and spinal cord. 



The reciprocal of the incubation period 

 has been found approximatelj' propor- 

 tional to the logarithm of the amount of 

 virus inoculated, thus serving to measure 

 the concentration of samples of virus. 

 Old mice less susceptible than young. 



Transmission : Experimentally, by in- 

 tracerebral, intranasal and intraperi- 

 toneal inoculation. Has been found to 

 persist in adult flies, Musca domestica L. 

 (M use I DAE) and other species, as 

 long as 12 days after experimental feed- 

 ing whereas mouse-adapted human polio- 

 myelitis virus persists only 2 days in 

 Musca domestica and not at all in some 

 other species. 



Serological relationships : Sera con- 

 taining antibodies to the Lansing strain 

 of human poliomj'elitis virus fail to pro- 

 tect against mouse poliomyelitis virus. 



Immunological relationships : Recov- 

 ered mice are immune to various hetero- 

 logous isolates or strains. No evidence 

 of immunological relationship with virus 

 of human poliomyelitis has been obtained, 

 save that mice paralyzed with mouse 

 poliomyelitis virus show some resistance 

 to infection with the Lansing strain of hu- 

 man poliomyelitis virus ; this has been 

 interpreted as possibly no more than an 

 interference phenomenon, since it seems 

 to depend on actual paralysis. 



Filterability : Passes Berkefeld X and 

 other Berkefeld filters and Chamberland 

 L3 filter. 



Other properties : Viable at least 14 

 months at —78° C ; at least 150 days in 50 

 per cent glycerine at 2 to 4° C. Most 

 stable near pH 8.0 and pH 3.3. Inac- 

 tivated readily at 37° C by 1 per cent 

 hydrogen peroxide. Particle diameter 

 estimated as 9 to 13 millimicrons from 

 filtration studies. Sedimentation con- 

 stant, Sjo" = 160 to 170 X 10-1' cm per 

 sec. per dyne. 



Literature : Bang and Glaser, Am. Jour. 

 Hj'g., 37, 1943, 320-324; Gahagan and 

 Stevenson, Jour. Inf. Dis., 69, 1941, 232- 

 237; Gard, Jour. Exp. Med., 72, 1940, 

 69-77; Gard and Pedersen, Science, 94, 

 1941, 493-494; Gildemeister and Ahlfeld, 



