I could be COMPLETELY wrong here, but I thought that the infection mechanic was more like how you can get an infected wound IRL. If the zombie infection is a virus, antibiotics and honey would do absolutely nothing to stop it. A virus can only be killed by your immune system or bacteriophages. But an IRL infection can def be cured with antibiotics or honey. And it makes sense that a rotting corpse would give you an infection. Even a bite from a person who brushes their teeth will give you one.
The zombie outbreak in 7d2d must be some kind of Mutated Hivemind Virus (of Alien or Nuclear Origin) OR Demonic in Nature. The zombies are slightly intelligent. They will always go for the easiest path to you, and are able to get other zombies to gang up on you. The screamer even works specifically as a scout to track down the player and summon a horde. It is worth noting as well that the virus (or whatever it is) only targets carnivores. Humans, Dogs, Vultures, and Bears are all considered "viable" by the virus, yet herbivores are completely unaffected. Hogs, Snakes, and Cougars are also unaffected as well though. Possibly because they are obsolete? Dogs are faster and more deadly than a Hog. Snakes are too slow. Cougars, while strong enough to kill a single human, are completely outclassed by Grizzly Bears, which are strong enough to kill a group of humans and fast enough to catch even Usain Bolt.
I think it's possible that the virus is infecting with a purpose. To create the most effective soldiers to spread the disease around.
But you cant ignore blood moons. While they rarely happen irl, they happen every week or even more often in 7d2d. If that isn't demonic, idk what is. Also the behemoth looks like it came straight out of doom so theres that. I don't think the virus is alien because it would be easier to just invade. Although maybe they spread it just to test on humans, not to invade earth.
(yes i know technically bears and humans are omnivores, and even dogs are to some extent, but in general we eat a LOT of meat.)