Cytology of Psittacosis Virus in the Sparrow (Zonotrichia)

Abstract

The great susceptibility of the representatives of the bird family Fringillidae for the psittacosis virus has previously 1 been emphasized. In the course of systematic studies relative to the various birds which might possibly serve as hosts for the virus, a series of white crowned (Zonotrichia leucophrys gambeli) and golden crowned sparrows (Zonotrichia coronata) were injected intraperitoneally with 0.3 to 0.5 cc. of a 10% organ suspension in broth of a mouse or Java bird—passage virus (mouse M.L.D. 10^-8). Many of the injected sparrows, which as a rule died in from 8 to 12 days, revealed at autopsy a diffuse plastic exudate teeming with free and intracellular Levinthal-Cole-Lillie bodies. The exudate covered both the pericardium and abdominal viscera. Victoria blue 4 R. was particularly useful to demonstrate the free elementary bodies. The liver necroses and the splenic tumor so commonly observed in the representatives of the Psittacidae and some of the Java birds infected with the psittacosis virus were missing. The exudate proved highly infectious and served as a useful antigen for various serologic reactions. Moist and dry fixed impression preparations stained by the Giemsa method and differentiated with acetone or methyl alcohol disclosed the developmental stages of the virus. Bedson and Bland 2 have reported the virus cycles in a rodent (mouse) and Bland and Canti 3 have described the growth phases of the psittacosis infective agent in chick embryonic tissue cultures. But since thus far no detailed records are available concerning the behavior of the virus in birds, it seemed advisable to analyze the cytology of the sparrow infection.

The young birds injected intraperitoneally were sacrificed at different intervals of time following the inoculations. Quantitative virus tests on mice accompanied the cytological studies on stained and unstained impression preparations of the exudate. The correlated findings on 25 different sparrow infections are as follows:

Although a casual examination of the preparations leaves little doubt that the development of the various virus colonies is entirely an intracellular cytoplasmic process, one encounters difficulties in demonstrating the early stages.