Comparative Study of Meningopneumonitis Virus, Psittacosis of Pigeon Origin, and Psittacosis of Parrot Origin by Henry Pinkerton, M.d., And

In a previous paper (1), the recovery of a virus morphologically identical with psittacosis from pigeons on a thiamin-deficient diet was reported. This virus, injected intracranially into mice behaved like typical psittacosis, producing fatal meningoencephalitis with typical elementary bodies. The virus differed from typical psittacosis, however, in that intraperitoneal injection in mice failed to produce apparent illness. Cross immunity tests with typical psittacosis were not carried out. The conclusion was drawn largely on morphological grounds that the virus was closely related to, if not identical with that of psittacosis. Francis and Magill (2), in 1938, described a virus recovered from ferrets inoculated with throat washings from human cases of an influenza-like respiratory infection. I t was not clear whether this virus was derived from the inoculated human materialor from the ferrets. In mice, it produced fatal meningitis after intracranial injection, and fatal pneumonitis after intranasal injection. Mter intraperitoneal inoculation, a fatal meningitis was produced in some mice. The hepatic necroses characteristic of psittacosis were not found. They were unable to identify their virus, and gave it a descriptive name--the virus of meningopneumonitis. Eaton, Beck, and Pearson (3) have recently reported the recovery of a virus from four cases of human atypical pneumonia by intranasal injection into mice. This virus, in its properties, was practically identical with the virus of Francis and Magill. I t showed immunological relationship but incomplete immunological identity with the latter virus and also with psittacosis. I t produced a fatal illness in mice, transmissible by intracranial or intranasal inoculation, but like our pigeon virus, was apparently non-virulent in mice when injected intraperitoneally. The experiments to be reported here were designed to test the hypothesis that these viruses might be related to the virus recovered from pigeons.