So Corny, try and follow this.... EHD requires hotter temps than we normally have in PA and high deer densities make outbreaks worse in spotty areas. EHD doesnt come to an area because of high deer densities. When it does come, an unusual event in PA, areas with too many deer are especially vulnerable. Had the outbreak in the SW occurred a few years ago, it simply could have been far worse.
Since EHD is not spread from deer to deer the higher densities do not make the effect of an outbreak more severe. Obviously more deer would die in areas with higher DD ,but there is no evidence that a higher percentage would die!