The inoculation of a chimpanzee with cultures and a passage strain of Bartonella bacilliformis induced local reactions which, while definite and characteristic, progressed less rapidly and were much less striking than those in the control rhesus monkey. Bartonella bacilliformis was demonstrated in the blood corpuscles with difficulty, and the fever was slight compared with the high and persistent fever of the rhesus monkey. In both the swelling of the lymph glands was an early symptom and constantly present. Definite anemia developed in the chimpanzee only after accidental infection with Rocky Mountain spotted fever and may have been due to either one or both infections, though it disappeared when the blood had become negative by culture for Bartonella bacilliformis and the local lesions had disappeared. Incidentally, the chimpanzee was found in this one instance to be less susceptible to the spotted fever than Macacus rhesus and guinea pigs.
In the ourang-utan, also, Bartonella bacilliformis induced a mild systemic and local infection. A rise of temperature occurred 10 days after inoculation) and fever continued for a week, though it was decidedly less severe than that in the control rhesus. The lesions induced by scarification were less definite than those which arose at the sites of intradermal inoculation. Bartonella bacilliformis was recovered from the blood on the 9th and on the 16th days after inoculation and from nodules excised on the 33rd and 53rd days. A few erythrocytes containing the organism were demonstrated in stained smears, but prolonged search was required to find them.
The symptoms and lesions observed in the chimpanzee and ourangutan as a result of infection with Bartonella bacilliformis are far milder than those of rhesus monkeys and show less resemblance to human Oroya fever or verruga.