H7 and HSV-2 infection blocked GJIC in WB cells. Dye transfer in WB cells using Lucifer yellow (A, C, E) or Texas Red Dextran (B, D, F) was used to demonstrate functional gap junctions since Lucifer yellow passes into adjacent cells but Texas red is not transported to adjacent cells due to its high molecular weight. In control cells, Lucifer yellow penetrated gap junctions (A) but both H7 (24 hr treatment, C) and HSV-2 infection (12 hrs post-infection, E) prevented spread of Lucifer yellow.