The process in which an organism effects a change in the type IV pilus-dependent motility of a symbiont organism (i.e. the controlled movement of a bacterial cell which is dependent on the presence of type IV pili, and which includes social gliding motility and twitching motility). The symbiont is defined as the smaller of the organisms involved in a symbiotic interaction.
modulation by host of bacterial type IV pilus-dependent motility