“…(1;2) Super infection exclusion has been described for a variety of human viral diseases including; influenza A, Rubella, hepatitis C, foamy virus, rhabdoviruses, HSV-1, vaccinia, flaviviruses and HIV-1 (Berg et al, 2003; Bock et al, 1998; Claus et al, 2007; Giannecchini et al, 2007; Lee et al, 2005; Mador et al, 2002; Nethe et al, 2005; Tscherne et al, 2007; Turner and Moyer, 2008; Whitaker-Dowling et al, 1983). In HIV-1 infection Nef, Env and Vpu down regulate cell surface expression of the CD4 receptor molecule (Nethe et al, 2005; Wildum et al, 2006).…”