<prompt> Von Magnus phenomenon?Is a normal replicative cycleVirus yield has low hemagglutinationVirus high infectivityVirus yields has high hemagglutination titre but low infectivity  <response>: When passaged serially in eggs,using as inocula undiluted infected allantoic fluid,the progeny virus will show high hemagglutinin titres ,but low infectivity. This has been called the Von Magnus Phenomenon and is due to the formation of incomplete virus paicles lacking nucleic acid. REF:ANANTHANARAYAN AND PANIKERS TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO.500 