1244 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Erxlebeii, snowshoe hare; L. californicits 

 Gray, jack rabbit ; Sylvilagus sp., cotton- 

 tail rabbit . 



Geographical distribution: United 

 States. 



Induced disease : In rabbit, benign 

 papillomas, having the form of small, 

 discrete, graj'-white, sessile or peduncu- 

 lated nodules, usually multiple, on lower 

 surface of tongue or, less frequently, on 

 gums or floor of mouth. 



Transmission : Perhaps by mother to 

 suckling young, with a latent period be- 

 fore onset of disease. Not highly con- 

 tagious, if contagious at all, in old animals. 

 Experimentally by puncture of tissues in 

 the presence of virus. 



Immunological relationships : Specific 

 immunitj' develops as a result of disease, 

 but no cross immunity with respect to 

 rabbit-papilloma virus, which differs also 

 in failing to act on oral mucosa. 



Filterabilily : Passes Berkefeld V and 

 N filters. 



Literature: Parsons and Kidd, Jour. 

 Exp. Med., 77, 1943, 233-250. 



7. Molitor sylvilagi spec. nov. From 

 Xew Latin Sylvilagus, generic name of 

 cottontail rabbit. 



Common names : Rabbit papilloma or 

 papillomatosis virus, rabbit wart virus. 



Hosts: LEPORIDAE— Sylvilagus sp., 

 cottontail rabbit. Experimentally, also 

 LEPORIDAE — Oryctolagus nmiadits 

 (L.), domestic rabbit. 



Geographical distribution : United 

 States. 



Induced disease : In cottontail rabbit, 

 at first minute elevations along lines of 

 scarification; later solid masses of wrin- 

 kled keratinized tissue, 3 to 4 millimeters 

 in thickness; eventually cornified warts, 

 striated perpendicularly at top, fleshy at 

 base, 1 to 1.5 cm in height; regression 

 rare ; natural papillomas become malig- 

 nant occasionally. In domestic rabbit, 

 experimentally, blood antibody remains 

 low but virus is always masked, prevent- 

 ing serial passage ; discrete lesions on skin 

 permit quantitative tests ; tarring causes 



localization of virus from blood stream; 

 papillomas give rise to malignant acan- 

 thomatous tumors by graded continuous 

 alteration; metastasis frequent; trans- 

 plantation to new hosts successful in 

 series ; antibody specific for the virus is 

 formed continuously in the transplanted 

 growths although virus is not directly 

 demonstrable by subinoculation from 

 them; malignant growths appear more 

 promptly and frequently where epidermis 

 has been tarred long; virus appears 

 specific for epithelium of skin; growths 

 disappear if treated with X-raj'S, 3600 r 

 at one time or fractionally; 60 per cent 

 are cured with 3000 r, but 2000 r ineffec- 

 tive. 



Transmission : Experimentally, by 

 scarification of skin. Abnormal suscepti- 

 bility to infection is noted in rabbit skin 

 treated with 0.3 per cent methylcholan- 

 threne in benzene or equal parts of tur- 

 pentine and acetone. 



Serological relationships : Specific neu- 

 tralization, reversible on dilution. Com- 

 plement fixation specific, with virus 

 particle as antigen ; no cross reaction with 

 antisera for vaccinia, herpes, fibroma, or 

 myxoma viruses. Precipitates occur in 

 properly balanced mixtures of virus and 

 specific antiserum; virus and antibody 

 in both free and neutralized states are 

 present in both soluble and insoluble 

 phases of these suspensions. 



Immunological relationships : Intra- 

 peritoneal injections immunize specifi- 

 cally. Rabbits immunized to fibroma 

 and myxoma viruses are susceptible to 

 rabbit papilloma virus. 



Thermal inactivation : At 70° C, not 

 at 65 to 67°C, in 30 minutes; in 0.9 per 

 cent sodium chloride solution at 65 to 66° 

 C, time not stated. 



Filterability : Passes Berkefeld V, N, 

 and W filters ; particle size calculated as 

 23 to 35 millimicrons by filtration as com- 

 pared with 32 to 50 millimicrons by cen- 

 trifugation and 44.0 millimicrons by 

 measurement of electron micrographs, 

 which show the particle to be approxi- 

 mately spherical in shape. 



