In the land of "The Walking Dead," everybody is sick, even if they don't know it yet.

That's never been more true than on season four of the AMC zombie series. Up until now, Rick Grimes and his band of survivors have only contended with flesh-eating walkers and power-mad humans. Now, they face an all-new enemy: a mysterious disease that claimed the life of McLovin lookalike Patrick at the end of last week's season premiere. Based on previews for tonight's installment, "Infected," the disease is only looking to spread further.

Read on for five of our predictions and theories going into "Infected."

It's Not Zombie Fever
Let's start with an easy one: Whatever killed Patrick — be it an airborne disease, something in the water, or something more sinister — it has nothing to do with the zombie virus. Don't forget that Violet the pig also died of what's very likely Patrick's Disease (as I'll call it until identified otherwise) as well, and animals do not "turn." At least, they haven't yet. I would hoot and holler at the sight of zombified pigs and horses as much as the next fan, but I don't think "Walking Dead" is going there. Patrick's Disease is something new, and potentially just as deadly as the virus that keeps the dead from staying dead.

Is Daryl Dying Next?
So, Patrick aside, who else is infected with Patrick's Disease? Hard to say until we see more, but there's one man you should definitely worry about: Daryl Dixon. The bow-hunting council-member not only shook hands with Patrick in the premiere, he shook hands with Patrick after licking his fingers. The show made a point of lingering on Norman Reedus stuffing his own fingers in his mouth pre-handshake, not just because it was such a GIFable moment, but also because of how the episode ends: with a very dead Patrick, sick with something horrible and unknown. If Patrick's Disease spreads by contact, Daryl is in serious danger.

What About The Kids?
Who else did Patrick spend time with in the premiere? Well, there's everyone at the barbecue to consider, but that's a pretty huge and unspecific group. Narrow the focus just a touch: Patrick was at the fence with Carl and the kids, was at Carol's secret knife-training class ... Patrick was with his age-group. What if Patrick's Disease only infects children? That would be a horrible left-turn for Carol, who has clearly invested so much of herself in these kids, likely a response to her own daughter's death. But it would be equally horrific for Rick, now that he's finally putting himself together; the last thing he needs is for Carl (or Judith, dare we even think it) to fall ill.

What's The Cure?
Well ... there might not be one. The fragile peace that held the prison together is likely to evaporate in the coming episodes, thanks to a circumstance our heroes can't control. As far as we know, Hershel and Bob are the closest things to doctors at the prison, serving as a veterinarian and an army medic respectively in their previous lives. That's not going to come in handy as far as manufacturing vaccines goes. And I sincerely doubt we'll see a return trip to the CDC, not after Jenner blew it to smithereens. No, I think there's no viable solution to Patrick's Disease, except ...

Exile or Die
Those are the options: cast out the sick, or let the disease fester and kill everyone inside the prison. It won't take long for Rick and the council to realize these are the options. They can quarantine their ill-stricken neighbors, but they can do little else to ease their suffering, save for a few well-placed bullets to the brain. Quarantine runs the risk of these sick patients somehow breaking loose and exposing others, too. Given the brutal decisions our "heroes" have already made in the past, I have to imagine they're up for making their most difficult choice yet in exiling any and all infected patients from the prison. Perhaps that's just a window into my own twisted mind and what I would do in the council's shoes, but I'm sticking with that prediction until proven otherwise.

What do you think will happen on "The Walking Dead" tonight? Leave your predictions in the comments section below!