Replication of chimeric viruses and controls in the brain of weanling mice. Groups of five-, three-week-old, SW mice per time-point were infected IC with 103 PFU of virus. Beginning on day 1 post-infection, and then every other day thereafter, groups of animals were euthanized and brains were harvested and homogenized. Virus titers were determined in Vero cells, with a limit of detection of 2 log10 PFU/g of brain. Data for rJEV India/78, JEV SA14-14-2 and rDEN4 are shown for two independent experiments (#1 and #2). The six, second-generation chimeric viruses and rDEN4 had titers at or below the limit of detection. Error bars represent the standard deviation (SD).