Persistence of Rickettsia Rickettsii in a Patient Recovered from Rocky Mountain Spotted Fever

Viable rickettsiae were isolated from the lymphatic tissues of a patient one year following recovery from Rocky Mountain spotted fever. The recovered agent was maintained by serial passage in guinea pigs and fertile hens' eggs. Identity of the isolated agent was established by: The development of specific complement fixing antibodies in guinea pigs.Direct visualization of the microorganisms in yolk sac tissues.The demonstration of its ability to afford cross immunity to a standard laboratory strain of R. rickettsii.