Answer:
A virulence factor helps pathogens become established, causing damage to the host. In gram negative bacteria that would be endotoxins from the bacterias outer membrane (LPS). In gram positive it would be a slime layer. In a virus it would be its spikes,isnce it helps the virus attach to the host cell. In bacteria it would be a immunoglobbin protease (enzyme), it breaks down the host immunoglobbins.