From the lungs of two fatal cases and from the sputum of two non-fatal cases of atypical bronchopneumonia, a psittacosis-like virus was isolated by direct intranasal inoculation of mice. Intraperitoneal injection of the same human material into mice gave negative results.
The virus has a relatively high virulence for mice by intranasal or intra-cerebral inoculation, but does not kill after intraperitoneal inoculation.
Its virulence for Java ricebirds is low and it fails to produce a carrier state in mice and birds.
Two cases showed an increase in complement-fixing antibodies to the new virus and to psittacosis.
The virus is antigenically related to the viruses of meningopneumonitis and psittacosis by complement fixation and by active immunity tests in mice.