The best approach for dealing with these infected comes down to understanding their movement patterns during different times. When night hits they become way more active and youll notice massive hordes forming up to 500 strong moving through the terrain. Their behavior is pretty consistent, they follow specific paths through the mountains and valleys of the region which you can use to your advantage especially when planning ambushes. Important to note that they react to pheromones, so if you spot a few gathering together, theres probably more coming since they basically call to each other chemically.

Getting the timing right is crucial since these hordes operate differently at night versus day. During daylight theyll usually hide in caves or buildings unless you really mess with them, but once it gets dark they become seriously aggressive. The terrain really matters here, when youre setting up for an encounter look for chokepoints in the landscape since the hordes will naturally funnel through them. Their ai is actually pretty sophisticated so dont expect them to just charge straight at you, theyll use the environment which means you need to think ahead about your position and escape routes. Maybe interesting that their behavior switches between group patterns when theyre far away and more individual actions when they get close, so your strategy needs to adapt based on distance.