1246 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



by them. Through air for a few inches. 

 Rarely by feeding. Experimentally, by 

 rubbing conj unctiva with a bit of infected 

 tissue or with a platinum loop contam- 

 inated from diseased conjunctiva; has 

 been recovered from flies. By injection. 

 By flea, Clenopsyllafelis iPULICIDAE), 

 rarely. 



Serological relationships : An attack of 

 the disease induces the formation of neu- 

 tralizing antibodies. Cross neutraliza- 

 tion by antisera to myxoma and fibroma 

 strains. Complement is fixed with myx- 

 oma virus as test antigen in the presence 

 of antisera to myxoma or fibroma strains. 

 Serum of rabbit inoculated with a soluble 

 antigen, a heat-labile protein with iso- 

 electric point near pH 4.5, agglutinates 

 myxoma elementary bodies. A second 

 soluble antigen, also heat labile, appears 

 distinct, inhibiting its own antibody even 

 after inactivation of its precipitating 

 power by exposure at 56° C. 



Immunological relationships : Myxoma- 

 recovered domestic rabbits become 

 immune to reinfection; fibroma-strain-re- 

 covered animals, although partially im- 

 munized, still support myxoma-strain 

 virus introduced into the testicle. Heat- 

 inactivated virus (60° C for 30 minutes) 

 tends to immunize if given intradermally ; 

 there is then an allergic local response, 

 less severe generalized disease, delayed 

 death or recovery. If fibroma virus pre- 

 cedes myxoma virus by 48 to 96 hours, 

 there is marked protection. 



Thermal inactivation: At 55° C in 10 

 minutes ; at 50° C in 1 hour. A substance 

 thermostabile for 30 minutes at 60 to 75° 

 C, but not at 90° C, is itself unable to 

 produce myxomatous changes after the 

 heat treatment but may do so in com- 

 bination with fibroma virus, and trans- 

 missible myxoma virus is then reconsti- 

 tuted. Although it is supposed by some 

 that this indicates the transformation of 

 fibroma-strain virus into myxoma-strain 

 virus, the possibility that heat-modified 

 myxoma-strain virus is reactivated has 

 not been eliminated. 



Filterability : Passes Berkefeld V and 

 N filters ; not Chamberland L5 or L7 

 filters. 



Other properties : Inactivated above 

 pH 12.0 and below pH 4.0. Withstands 

 drying. Viable at least 3 months at 8 to 

 10° C. 



Literature : Aragao, Brazil-med., B5, 

 1911, 471; Mem. Inst. Oswaldo Cruz,^0, 

 1927, 225-235; Berry and Dedrick, Jour. 

 Bact., 31, 1936, 50-51 (Abst.) ; Berry and 

 Lichty, ibid., 31, 1936, 49-50 (Abst.); 

 Berry et al.. Second International Cong- 

 ress for Microbiology, Report of Proceed- 

 ings, London, 1936, 96 (Abst.) ; Fisk and 

 Kessel, Proc. Soc. Exp. Biol, and Med. 

 29, 1931, 9-11 ; Gardner and Hyde, Jour 

 Inf. Dis., 71, 1942, 47-49; Hobbs, Am 

 Jour. Hyg., 8, 1928, 800-839; Science, 73 

 1931, 94-95; Hoffstadt and Omundson 

 Jour. Inf. Dis., 68, 1941, 207-212; Hoff 

 stadt and Pilcher, Jour. Bact., 35, 1938 

 353-367; 39, 1940, 40-41 ; Jour. Inf. Dis. 

 64, 1939, 208-216; 65, 1939, 103-112 

 Hoffstadt et al., ibid., 68, 1941, 213-219 

 K. E. Hyde, Am. Jour. Hyg., 23, 1936 

 278-297; R. R. Hyde, tbid., 30 (B), 1939 

 37-46, 47-55; Hyde and Gardner, ibid. 

 17, 1933, 446-465; 30, (B), 1939, 57-63 

 Kessel et al., Proc. Soc. Exp. Biol, and 

 Med., 28, 1931, 413-414; Lipschutz 

 Wien. klin. Wchschr., .^0, 1927, 1101-1103 

 Lush, Austral. Jour. Exp. Biol, and Med 

 Sci., 15, 1937, 131-139; 17, 1939, 85-88 

 Martin, Austral. Counc. Sci. and Indust 

 Res., Bull. 96, 1936, 28 pages; Moses 

 Mem. Inst. Oswaldo Cruz, 3, 1911, 46-53 

 Parker and Thompson, Jour. Exp. Med. 

 75, 1942, 567-573; Plotz, Compt. rend 

 Soc. Biol., Paris, 109, 1932, 1327-1329 

 Rivers, Jour. Exp. Med., 51, 1930, 965- 

 976; Rivers and Ward, ibid., 66, 1937 

 1-14; Rivers et al., ibid., 69, 1939, 31-48 

 Sanarelli, Cent. f. Bakt., I Abt., 23 

 1898, 865-873; Shaffer, Am. Jour. Hyg. 

 34 (B), 1941, 102-120; Shope, Jour. Exp 

 Med., 56, 1932, 803-822; Smadel et al. 

 ibid., 72, 1940, 129-138; Splendore, Cent 

 f. Bakt., I Abt., Orig., 48, 1909, 300-301 

 Stewart, Am. Jour. Cancer, 15 Suppl., 



