It has been many years since we were locked into the quarantine zone. Over this period of time, I have learnt quite a bit about these creatures.
The first thing is that other than the rarer variants, the more common 'drones' have several means of infecting the healthy.
The first is by a straightforward chase. The infected chase down their prey with the goal of inflicting any wounds with their blood covered nails and teeth and bladed weapons.
The second is by herding. When prey proves itself too difficult to catch, the drones use an assortment of means to communicate with each other in order to set a trap for the prey to walk into.
The third method is the raid where after finding a group's shelter, a hoard overruns the settlement. Although zombies aren't too keen on killing themselves except for during phase 1, they are driven to sacrifice themselves to infect the shelter.
Although these 3 strategies are difficult to deal with, as long as survivors avoid large settlements and keep in mind that zombies are nearly blind and deaf and rely mostly on sense of smell to find healthy people, drones aren't too much trouble.
That is of course, as long as you avoid the two other variants of infected. I simply call them the 'brain' and the 'scout'. Brains, as the name would suggest, have enough intelligence to not only trick humans with elaborate plans but can also make use of the numerous drones to avoid putting themselves in danger. They also learn quickly so don't be quick to catch the attention of a motorist or driver passing you by.
The last is the scout. They are the hunting dogs of the brains. Not only has the virus modified them for speed, but they also have better senses than drones though for some reason, they eat drones whenever there are no people to infect and are in turn eaten by the brains. I have since learnt the reason for this.
The reason for the infected cannibalizing their own is to prepare for the Generation Puppy or Gen P for short. The brain's body is converted into a large sac in which intelligent canines are cloned. In these canines are dormant cells of the virus which remain dormant until about a month after being introduced into a human it cannot infect other animals but can remain in their saliva and on claws for about 2 weeks before dying.
I believe this long period of dormancy is to give the canine time to disappear. The Gen P can also produce Gen P young through reproduction even with non-Gen P partners.
When a person is bitten by Gen P, they find themselves unusually active after the first week, they tend to be targeted by animals and any attempting to help them will suffer a similar fate. In this way, by the time they inevitably turn infected, they would have helped infect quite a number.
If you find this, you have guts for coming so far into the dead zone. If you find this and can read it, well, note that only the infected can read this.