Observations on Psittacosis in Mammals.

Abstract

The observations of Bedson, 1 Krumwiede, 2 Armstrong, 3 and their coworkers indicate that the etiological agent of psittacosis is a filter-passer and in all probability not an ordinary bacterium. Moreover, it has been shown that, in addition to parrots, certain small birds, e.g., parrakeets and love-birds, are susceptible to the disease. Furthermore, Krumwiede, McGrath, and Oldenbusch 2 have been able to produce the disease in mice and to pass it in series by means of intraperitoneal injections of emulsions made from a mixture of the liver and spleen of infected animals. In view of the fact that man is susceptible to psittacosis and that certain birds, with which most of the experimental work in the past has been done, have the disease spontaneously and may be carriers of the virus, it seemed desirable to determine if mammals other than the mouse are suitable for experimental purposes in this field of investigation. The object of the present communication is to report that rabbits and guinea pigs are experimentally susceptible to psittacosis† provided they are inoculated and handled in a certain manner.

We have been able to confirm Krumwiede's observations concerning the susceptibility of mice to psittacosis. For many reasons, however, that need not be discussed here, the mouse proved to be an unsatisfactory experimental host. Therefore, we decided to investigate the susceptibility of other mammals to psittacosis. Rabbits and guinea pigs were inoculated intradermally, subcutaneously, and intraperitoneally with infectious emulsions of liver and spleen obtained from parrots.

The results were of uncertain significance, and it soon became obvious that, if these animals were to be used, another procedure of handling them would be necessary.