STUDIES ON THE ETIOLOGY OF SPONTANEOUS CONJUNCTIVAL FOLLICULOSIS OF RABBITS

Abstract

Before summarizing the experimental results presented herewith, a brief review is indicated of our study on follicular conjunctivitides existing in the different species of animals thus far examined. Spontaneous follicular conjunctivitis of monkeys and chimpanzees, which resembles the early, or follicular, stages of human trachoma, has been shown to be an infectious disease, and to arise from the action of a bacterium and not an ultramicroscopic virus (2, 10). A new species of organism, designated tentatively as Bacterium simiae, n.sp., and capable of reproducing granular lids in normal monkeys and apes, has been recovered from cultures of simian folliculosis tissues. This organism, although of a different species, is of the same genus as Bacterium granulosis which is associated with human trachoma (3). The studies were extended beyond folliculosis in monkeys and apes to a similar disease widespread among stock rabbits. Its clinical appearance and microscopic changes resemble the spontaneous malady in simians with some minor differences (1). Like the latter, rabbit folliculosis was also shown to be infectious and contagious. In the present paper a bacteriological investigation of the rabbit affection is described. In the experiments undertaken we followed the method used by Noguchi in his studies on trachoma, that is, the different organisms recovered from normal and affected conjunctivae were inoculated into the conjunctivae of selected, quarantined rabbits. Among the bacteria thus isolated from folliculosis tissue a new species was disclosed that brought about conjunctival reactions apparently indistinguishable either from the disease seen in nature or from the experimental infection induced by inoculation of folliculosis tissue. The organism was specifically active in rabbits whether injected subconjunctivally or instilled into the conjunctival sac. Furthermore, the special bacterium has thus far been cultivated only from folliculosis cases and not from other forms of conjunctivitis nor from normal tissues. Finally, specifically pathogenic strains of the identical microorganism have been recovered from rabbits experimentally infected with the bacterium. A distinctive feature of this bacterium is that it is of the same genus as the microorganisms heretofore designated as Bacterium granulosis and Bacterium simiae. It is clearly evident then that the three bacteria cultivated to this time form a new genus, for which we propose the name Noguchia. The diagnosis of the genus has already been described in this paper, but as was also shown in a foregoing section, certain specific characters differentiate the three. Accordingly, we suggest a change in the names of the granulosis and simiae species to the proposed binomials, Noguchia granulosis, n.sp., and Noguchia simiae, n.sp. The specific organism, having an evident causal relationship to rabbit folliculosis, can therefore be placed in this classification, with the name of Noguchia cuniculi, n.sp. In conclusion it would appear that in three types, at least, of follicular reactions in the conjunctiva—in man (the primary lesion of trachoma consisting essentially of follicles), in the simian, and in the rabbit—there is an intimate association of microorganisms having the same generic, but different specific properties.