The Number of Particles of Sericesthis Iridescent Virus Required to Produce Infections of Galleria Larvae

Abstract

For the majority of viruses, the ratio of total countable particles to infective units is more than 10 : 1. Reasons underlying these ratios are reviewed by Sharp (1965) and by Wildy and Watson (1962). Cheng (1961), Kaplan and Valentine (1959), and Overman and Tamm (1956) report infection ratios closer to unity, all using in vitro assays on cell suspensions or on chorioallantoic membrane. In this paper we shall show that Sericesthis iridescent virus (SIV) has high infectivity when assayed in the intact host.