Comparative Study of Meningopneumonitis Virus, Psittacosis of Pigeon Origin, and Psittacosis of Parrot Origin

Abstract

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. It 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. It showed immunological relationship but incomplete immunological identity with the latter virus and also with psittacosis. It 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.

Further Laboratory Studies on the Classification of Psittacosis-Like Agents

“…The viruses of psittacosis (parrot origin) and ornithosis (pigeon or chicken origin) have been differentiated on the basis of source (9, 13), intraperitoneal virulence in mice (2, 9, 13), and intracerebral virulence in pigeons (15). Our results also suggest that antigenic differences may be demonstrated by the intracerebral cross immunity test in mice.…”

“…One bird had antibodies to strain Cal 10 antigen prior to inoculation with type strain S-F. According to other authors (9,15), the presence of complement-fixing antibodies did not necessarily render a pigeon immune to an intracerebral inoculation with ornithosis virus. Whether this lack of immunity in thepresence of complement-fixing antibodies is applicable to strain S-F is difficult to conclude because of its low pathogenicity for pigeons.…”

“…The usual findings were loss of appetite, ruffled feathers, progressive weakness, and finally death. Contrasted with this, those receiving strain ornithosis manifested marked neurological symptoms, the most prominent being opisthotonos (2,15). The neck was drawn back and soon the bird was unable to stand.…”

Studies on Lymphogranuloma Venereum

“…However, following upon the report of Phair, Smith, and Root (23) on the high specificity obtained with chicken sera prepared against the meningococcus, a few sera were prepared in chickens. Because of the susceptibility of chickens to ornithosis (24) and because of the demonstrated close relationship between members of the lymphogranulomapsittacosis group of agents (1)(2)(3)(4)(5), it was decided to use only toxoid in these chickens. Following the use of toxoid, antitoxins have been obtained from chickens which have titers as high as those induced by inoculation of toxins, and far higher than those induced by inoculation of toxoids, in rabbits.…”

“…For many reasons it has been suspected in this laboratory that the agent of lymphogranuloma venereum, and the other agents which have been shown to be closely allied to it (1)(2)(3)(4)(5) should be separated from the true viruses and established in a group by themselves, comparable to the R i c k e t t~ for example (6). It had also been suspected that the agent of lymphogranuloma venereum at least, with which we have had most experience, produces a toxin.…”