ETIOLOGY OF OROYA FEVER : XII. INFLUENCE OF MALARIAL INFECTION (PLASMODIUM INUI?), SPLENECTOMY, OR BOTH, UPON EXPERIMENTAL CARRION'S DISEASE IN MONKEYS.

The experiments reported were designed to determine the influence of malarial infection (Plasmodium inui?), splenectomy, or both combined, upon the course and character of experimental infection with Bartonella bacilliformis in monkeys (Macacus rhesus and M. cynomolgus). Blood withdrawn from a monkey showing spontaneous malarial infection was inoculated intravenously into monkeys (a) 1 month prior to inoculation with virulent verruga material, (b) simultaneously with the verruga material, and (c) during convalescence from verruga infection of moderate severity. All the monkeys contracted the malarial infection and suffered one to three paroxysms during a period of about a month. The verruga lesions appeared in the inoculated animals in due course, were of average size, remained for the usual length of time, and Bartonella bacilliformis was recovered in culture from blood which also contained the plasmodia. The lesions in the convalescent animals continued to heal at the normal rate, and blood cultures were negative for Bartonella bacilliformis, as is usual during convalescence. One of the recovering animals was reinoculated with virulent verruga material a month after the injection of the malarial blood, but neither did new lesions arise nor old ones recur. The malarial infection, therefore, had no effect upon the course of verruga or upon the establishment of immunity to Pattonella bacilliformis, hence it would appear that malaria and verruga may coexist in the same individual without unfavorable effect of one disease upon the course of the other. Similarly, splenectomy led to no appreciable aggravation of Bartonella infection. One monkey subjected to splenectomy and inoculated with verruga material shortly afterwards had an unusually severe reaction, but another, which was infected with material from the first and simultaneously splenectomized, reacted only moderately, while the non-splenectomized control showed a severer type of cutaneous infection. Even the combination of splenectomy and malarial infection did not appreciably aggravate the experimental verruga. Neither relapse of verruga nor reinfection with Bartonella bacilliformis was induced in convalescent or recovered monkeys as a result of splenectomy.