node imprint preparations, these organisms stain bluish with Giemsa's stain and faintly by Castaneda's method. Gram-negative. Cultivation: Will not grow in ordinary bacteriological media or in embryonated chicken eggs. Has been grown in certain tissue-culture explants from infected dog- node tissues. Immunology: Recovered dogs are solidly immune to reinfection, but mild febrile relapses may occur during which infection is recoverable from the blood. Guinea pigs injected with this agent are not cross- immunized against Rocky Mountain spotted fever, endemic typhus or Q fever. Natural resistance in dogs has not been observed, but dogs have been immunized by infectious materials of reduced virulence which have caused mild or inapparent infections. Serology: Attempts to prepare a usable antigen from heavily infected dog nodes have not been successful, and no other source of antigen is yet available. Hyper- immunized dogs and rabbits have shown no common antigenic factor with strains of Proteus vulgaris. Resistance to chemical and physical agents: Inactivated within a few hours in a saline suspension at room temperature. Dog nodes frozen at —20° C. have remained infectious for at least 158 days but survive more consistently at — 70°C. Survival under lyophilization is short. Antibiotic therapy: Symptoms in ill dogs quickly alleviated by oral administration of aureomycin or terramycin, as little as 250 mg in 15-pound beagles. Sulfonamids also effective in treatment. Pathogenicity: Untreated dogs show up- wards of 90 per cent mortality after feeding on infected fish or when injected with in- fected dog tissues and blood. Foxes and coy- otes are also susceptible. Causes mild re- sponse in guinea pigs, hamsters and white mice; this response is retrogressive on passage and is not maintained. Raccoons and mink do not show clinical reactions to attempted experimental infections. Trout are not infected by injection of infected dog- node suspensions. Source: First observed in node-imprint preparations of experimentally infected dogs by Cordy and Gorham (Amer. Jour. Path., ^6, 1950, 457). Habitat: Found in the intestinal trema- tode Nanophyetus salmincola (Chapin), which probably acts as the natural reservoir of infection. The etiological agent of a sal- mon-poisoning disease of canines. TRIBE III. WOLBACHIEAE PHILIP, 1955. (Bact. Rev., 19, 1955, 271.) Wol.ba.chi'e.ae. M.L. fem.n. Wolbachia type genus of the tribe; -eae ending to denote a tribe; M.L. fem.pl. n. Wolbachieae the Wolbachia tribe. Includes many species heretofore assigned to the genus Rickettsia which are rickettsia- like in growth and in morphological and staining properties and which are mostly intracel- lular symbiotes or parasites of various species of arthropods, sometimes occupying special tissues or mycetomes. Characterization has often been not so adequate as in the preceding forms that are pathogenic for vertebrates, and differentiation has been arbitrarily assigned chiefly on the basis of presumed host-specificity in arthropods, though differences in devel- opment and morphology are often noted. At present three genera are recognized in the tribe Wolbachieae; however, future knowl- edge may show that a better and more satisfactory arrangement is possible. Key to the genera of tribe Wolbachieae. I. No known filterability; no reported association with intracellular crystalline inclusions. A. Symbiotic to highly pathogenic; no mycetomes produced in hosts. Genus VI. Wolbachia, p. 953.
