Observations on the Growth of Psittacosis Virus in Chorioallantoic Membranes by Electron Microscope

Abstract

Psittacosis virus infection is evidently an adsorption of the infectious particle on the cell surface. Following 4 hrs.'' contact of virus bodies with tissue, only 1% of infectious particles remain suspended in fluid, the remainder having formed an attachment to the membrane. This is confirmed by the rapid decrease in activity titer of allantoic fluid inoculated with infectious particle. Membrane replica studies of infected tissue in which virus particle imprints disappeared 5 hrs. after inoculation suggests progress beyond adsorption phase and practically complete penetration. Changes in shape of imprints from elevations to cavities and holes following inoculation suggests cell penetration. Observations with electron microscope on psittacosis virus purified from allantoic fluid revealed one small, centrally dense particle and another large flat body. Both particles had common antigenic factors. Virus-like particles from infected membranes and allantoic fluid have similar over-all size range differing principally in distr. of particle sizes. The morph. of particles seen in allantoic fluid and those obtained from infected membrane are similar. 72-hr. infected membrane virus is in an earlier phase than the particles from 5 to 6-day cultures of allantoic fluid. Virus multiplication is discussed.