Is DS3 the same as D2S3? I've seen D2S3 cited as DS3 in some places so I think they are interchangeable. The following paper describes the process by which D2S3 was selected:
Bennett et al. (2005) "Selection of D2S3, an Aedes aegypti (Diptera: Culicidae) strain with high oral susceptibility to Dengue 2 virus and D2MEB, a strain with a midgut barrier to Dengue 2 escape." J Med Ent 42(2): 110-119.
Slightly off-topic, but there was an interesting paper a few years ago (link below) indicating that small numbers of cells were involved in VEEV infection of Aedes tritaeniorhynchus too.
(From the abstract: "The numbers of midgut cells infected averaged 28, and many infections were initiated in only 1-5 cells.")
Anthony James Wilson, the same group now predicts a higher number of infected cells (21-433) with the same virus and mosquito. Still only a small proportion of cells.
Demographics of natural oral infection of mosquitos by Venezuelan equine encephalitis virus
Serafín Gutiérrez1,2⇑, Gaël Thébaud3, Darci R. Smith4, Joan L. Kenney4 and Scott C. Weaver4⇑