PSITTACOSIS : II. EXPERIMENTALLY INDUCED INFECTIONS IN MICE.

The work presented in this communication concerning psittacosis in mice confirms Krumwiede's observations that mice inoculated intraperitoneally with emulsified livers and spleens containing the virus develop the disease and that the malady can in this way be passed serially through a number of mice. Furthermore, it has been shown that mice are susceptible to the virus administered intracerebrally and that the active agent can be propagated indefinitely by means of brain to brain inoculations. Moreover, by the use of mice, the presence of the virus of psittacosis in the sputum of a patient with the disease has for the first time been demonstrated. It follows that the mouse is available for diagnostic purposes. The pathological findings in infected mice consist of enlarged fatty livers that frequently show areas of necrosis infiltrated with polymorphonuclear and mononuclear cells; enlarged spleens with areas of necrosis and cellular infiltrations involving the pulp and lymphoid follicles; and, finally, in intracerebrally infected animals, a meningoencephalitis. The "minute bodies" described by other observers were not found in all animals, but they were seen with sufficient frequency in smears of peritoneal and meningeal exudates and in smears and sections of livers and spleens to demand serious consideration as the possible etiological agent of the disease. Neutralizing and protective antibodies were not found in convalescent human sera when the mouse was used as the test animal.