ETIOLOGY OF OROYA FEVER : VIII. EXPERIMENTS ON CROSS-IMMUNITY BETWEEN OROYA FEVER AND VERRUGA PERUANA.

Nine monkeys (Macacus rhesus) and a chimpanzee which had recently recovered from an infection with the Oroya strain of Bartonella bacilliformis were tested for immunity against the verruga strain of Bartonella bacilliformis as well as against the homologous strain. Complete immunity to both strains was demonstrated. The result establishes the identity of the strains and is in agreement with the result of comparative serological study. The criteria of recovery include not only the subsidence of febrile reactions and local lesions but also a negative result of cultural tests of blood and lymphatic gland tissue. Recovery may occur as early as 1 month after inoculation, but in most instances a period of 2 to 5 months is required for the completion of convalescence.