Swish Lightning Zaps

As stems from the Eternal Swish , this particular ailment is brought on when someone is struck by lightning from one of this phenomenon's many offshoot storms. You might think that this would simply be a lightning strike, but unfortunately it's rather different and a bit more difficult to deal with.  

It Will Find You

The primary difficulty is that the lightning actively seeks you out. While it is possible to avoid, it's exceedingly difficult and about half the time you should probably just let it happen. People with heart conditions should probably just leave now.
One way to avoid getting struck is staying low to the ground, and being under the age of ten, or keeping someone under the age of ten close to you.

But it's Not Really Lightning

Fortunately, despite some visual similarities and the inclusion of an electrical shock, it's not actually lightning. Don't feel like going into the exact scientific nature of the zaps, but at least you're not getting fried. You are being exposed to something that will try to change your genetic structure, but it's unsuccessful.
You'll develop some sort of rash in the area where you were struck, in addition to the initial sting. It can be quite painful, and usually lasts for about a week, but then the foreign matter will be expelled.

Uninhabitable

Beyond the rather erratic storm conditions of Villain Central , it's this sickness that makes the region somewhat uninhabitable. Not that people don't still live there anyway, but it's what made Canada and the US leave the area alone despite the fact that it was entirely taken over by a supposedly villainous organization.
There was also the idea that lightning strikes, formerly a fairly rare thing, became extremely common.

Origin

Natural

Cycle

Short-term

Rarity

Uncommon