Electron microscope study of mosquito densonucleosis virus maturation

Maturation of mosquito densonucleosis virus (MDV) was studied in its natural host, Aedes aegypti L. larvae. First ultrastructural changes were observed in the cytoplasm of virus-infected cells. They consisted in the formation of paracrystalline structures containing particles 18--20 nm in diameter as well as microtubules 20 nm in diameter. Virogenic stromas and paracrystalline virion arrays were found in the nuclei of virus-infected cells.