Abstract
The infection of cultured cells of the fruit fly Drosophila melanogaster (Schneider) with vesicular stomatitis virus (VSV) led to the establishment of persistent non-cytocidal infection. After weeks or months of persistent infection many VSV variants or mutants were detected all of which showed increased capacity for growth in these insect cells. We present a preliminary characterization of these viruses arising in the Drosophila cells.