Spontaneous folliculosis of Macacus rhesus monkeys—a type of follicular conjunctivitis associated with marked, local, inflammatory reactions—is apparently a disease sui generis, due to a specific infectious agent. It can be transmitted from monkey to monkey by means of subconjunctival injection of suspensions, and by conjunctival swabbing of the secretions, of affected tissues, or by contact of normal animals with folliculosis monkeys.
The agent causing folliculosis has failed in our hands to pass through Berkefeld and Seitz filters, even those of an unusual degree of permeability; and the lesions that it causes show no cellular inclusions suggestive of the action of a virus. The condition is due apparently to an organism of low grade pathogenicity. The essential histopathological structure corresponds to that of a folliculoma (16) which, while not identical with a granuloma, bears certain resemblances to the latter.
The studies here reported concern only one species of monkey, Macacus rhesus. Further investigations will be carried out on different species of Anthropoidea and other animals.