No sane adult likes getting sick. When we were young and wanted to get out of school, catching the occasional cold or flu must have felt like a godsend. This, however, becomes less of an option as we age and more responsibilities get thrown at us. Thankfully, many of the diseases we will experience in our lifetime have cures or are treatable. In the world of comics, people aren't so lucky.

RELATED: 10 Reasons Death in Comic Books is Meaningless

Not only will characters come up against a disease that may or may not have a cure, but those same diseases might be caused by something monstrous or have horrifying symptoms we cannot even fathom. We're not just talking about zombie viruses (although we've got you covered), we're talking about diseases that would make Doctor House faint if any of them were real. So schedule an appointment with the CBR Clinic and check out the fifteen most iconic comic book diseases!

15 Cat Flu

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The dystopian world of David Russel and Ben Caldwell's "Prez" is an oddball one, taking its cues from the modern zeitgeist, and from Warren Ellis and Darrick Robertson's "Transmetropolitan." Such a strange world deserves strange diseases, and Cat Flu is no exception.

Cat Flu is a wasting illness which is spread, as you might imagine, from cats to humans. While seemingly asymptomatic in our feline friends, it has claimed thousands of lives in the "Prez" universe. Naturally, it has people running scared as the death toll climbs and U.S. citizens demand a cure. However, big businesses are holding off on developing a cure and the cats have defenders in the form of religious extremists who see viruses as the true inheritors of the Earth.

There are two scenes in "Prez" that illustrate the madness of the epidemic well. One shows a group of people running from a cat as it approaches them in the street. Another shows a convenience store clerk aiming a cat at a pair of armed robbers. Meow-velous imagery there! Ha-ha! Ah...

14 The Teen Plague

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Simply called the Teen Plague or The Bug, this virus is one of many sexually-transmitted diseases on our list and comes to us from Charles Burns' coming of age graphic novel "Black Hole." It's not nearly as bad as some of the other diseases in comics, but it's disturbing nonetheless.

The Bug is an STD that physically alters the host's body. Some characters in "Black Hole" get off light by simply growing a tail or something equally benign. Other characters are less fortunate. Someone with The Bug might grow an extra mouth that speaks their innermost thoughts or start shedding their skin like a snake. You also might end up with messed up features, like the face of a basset hound.

Gross, right? Thankfully, anyone who catches The Bug doesn't develop any other symptoms and is in no great peril. Really, the only symptoms are becoming difficult to look at and becoming reviled by your peers. Since The Bug is actually meant to represent the ugliness of youth and adolescence, however, all of this makes more sense as what we see is more of a metaphorical disease. Still, we wouldn't want to take our chances in this part of small town America.

13 T-O Virus

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Not to be confused with hip-hop icon T.I., T-O actually stands for Techno-Organic Virus.

This is a disease found in the Marvel comics universe. Brought to Earth by the Technarchy, the T-O Virus infects organic material and rewrites it into a kind of living technology. One common strain used by the Technarchy is the Transmode virus, which transmits via skin-to-skin contact and is used to harvest the life forces of infected creatures. Said infected creatures are known to be able to shape-shift and run the risk of becoming part of a hivemind race called The Phalanx if left unharvested.

Would-be despot Apocalypse once ended up with a version of the T-O Virus (as if the Marvel universe didn't have enough to worry about) and used it to infect Cable. He managed to obtain it from Mister Sinister, the mad geneticist who originally developed the virus as a means of killing Apocalypse once and for all. We'll let you guess how that turned out.

12 G+

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Ever wanted superpowers? That's a dream that a lot of people have. It's why so many of us turn to comics to begin with: because we want to be able to see ourselves in these four-colored flights of fancy. Found in the pages of Monty Nero and Richard Dowling's "Death Sentence," G+ is a disease that grants that wish. Another STD, anyone infected with G+ develops a myriad of super-powers. You might gain the ability to fly or phase through matter or turn into a human bomb. Sounds cool, right?

Too bad you also die in six months.

With no known cure or way of suppressing the virus (presumably because infected people keep blowing up clinics by accident), G+ sufferers are given a glimpse of godlike powers during their last few months alive. One common thread among the infected -- especially among the sexually-frustrated artist protagonists of the series -- seems to be that their powers are somehow linked to artistic expression.

11 Legacy

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Another Marvel pathogen, the Legacy virus comes to us from the horrible, horrible mind of Apocalypse. Oh, yes: T-O wasn't the only bug up his sleeve. Legacy is a virus afflicting the mutant population and becomes active when a mutant uses their powers. The disease takes hold and begins slowly shutting down all bodily functions until the host finally dies.

Legacy isn't the kind of disease to let you go out quietly, of course. After all, this is the Marvel universe! Forget holding someone's hand on their deathbed, people infected with Legacy experience one final explosion of super-powered glory before sending them ungently into that good night -- and probably singing with a few angels on the way up.

There's another version of this virus that is designed to infect humans, although we don't get any cool flare-ups of our mutant powers. Not that we have any worth writing about. Oh, digesting milk slightly faster? Thanks, Legacy.

10 Clench

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Batman's dealt with a lot of crap over the years. From thwarting Joker's arms-deal with the Ayatollah of Iran to racing across time and space in order to defeat a man who may or not be his father (or Satan himself), Batman's just about done it all. Did you know, for example, that he once saved Gotham City from a particularly devastating plague?

Developed by the always-pleasant Order of Saint Dumas, Clench is a deadly strand of Ebola lovingly referred to by the Order as "The Apocalypse Virus." The virus changes the host body until their death, which is signalled by bleeding from the eyes. What's scary about this virus isn't just its horrible pedigree, but the fact that it will kill you in 12 hours. The end result is a frantic race against time as Batman has his crew, frenemy Catwoman and actual enemy Penguin hunt for a cure before all of Gotham kicks the bucket.

9 The Good Time Sloth

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In evolutionary biology, memes are probably best described as viral ideas that influence a species' development for better or for worse. In internet culture, memes are jokes, images, concepts and bits of lingo that are shared en masse across the information superhighway. In the comic "Memetic" by James Tynion IV and Eryk Donovan, the Good Time Sloth is both of those things.

On first viewing, the Good Time Sloth is an innocent picture of a sloth, smiling and giving a hearty thumbs-up signal in front of a simple black-and-white spiral. First-time viewers of the GTS meme end up overwhelmed with euphoric joy, but whatever happiness they feel after that point is quickly replaced with murderous rage. Not everyone is affected by the disease, mercifully. People who are colorblind or have myopia are immune to the sloth's effects. Too bad it means the rest of us turn into rage zombies... but hey, good for them!

8 The Beauty

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Our next STD is The Beauty, which comes to us from Jeremy Haun and Jason A. Hurley's Image miniseries, er, "The Beauty." On the surface, the Beauty actually seems like a pretty good deal for some people. It's a disease that fixes your physical imperfections. Excess body hair? Stocky frame? Weak chin? One night of unprotected sex with someone who has The Beauty will take all of that away and make you a radiant, picture-perfect hottie version of yourself. Too bad it also turns you into a walking firebomb.

That's right: for reasons that are explained as the series goes on, anyone who becomes infected with The Beauty eventually immolates from the inside-out, leaving only a crispy husk of your sexy new self behind. This is already pretty horrifying, but it's about to get worse: over two hundred million people in "The Beauty's" United States are infected with the virus. And trust us when we say that the cure is almost as bad as the disease.

7 The Gendercide

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There's not much to say about the pandemic found in Brian K. Vaughn and Pia Guerra's "Y: The Last Man" without giving too much away. To be honest, the plague is such an enigma that it doesn't even have a proper name. That heading you just saw refers more to the event it caused rather than the disease itself. So, what was the Gendercide? To put it simply, it was the result of a worldwide plague that struck all at once and caused every male mammal on Earth to suddenly hemorrhage and die.

All of them. No exceptions. Founded a charity? You're dead. Robbed a bank? Also dead. Flying a plane? Oh, you're dead. Also, so is everyone else on the plane you were flying and they're going to kick your butt in Heaven or Valhalla or wherever you're going. The exact pathology of the disease is never made entirely clear. All we know is that the main character and his pet monkey were the only males to survive, trapped in a world without Neil Degrasse Tyson's soothing voice.

6 Despotellis

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What's worse than a regular virus? A virus that can think on a human level, or higher. What's even worse than that? How about a sentient virus that has the power of a Yellow Lantern? Pneumonia's a pretty bad disease, but once you give it a grudge against humanity and the power of a cosmic fear-powered death battery, well, that's when we've all got a bad time on our hands.

That's what you get with Despotellis, one of the newer villains of the D.C. Universe. Created as a super weapon by an alien race, Despotellis was designed to be the ultimate killing machine. As expected, he was too perfect. Eventually, Despotellis became sentient and rebelled against his creators (because what else is he going to do?). One of his abilities is to create clones of himself at rapid speeds and slowly kill his hosts. Not long after getting loose, Despotellis was able to destroy all life on his home world in under a day. With a resume like that, becoming a Yellow Lantern was only a matter of time.

5 The Empty Man

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The mind is such a fragile thing. The slightest nudge in the wrong direction can send someone over the edge. Ever wonder what someone sees when they go mad? Cullen Bunn and Vanesa R Del Rey know.

In "The Empty Man," the titular disease springs up in people with precognitive leanings, even though at first glance it seems to strike anyone at any time. Once you contract The Empty Man, you start to hallucinate and begin engaging in some destructive behaviors, either towards yourself or those around you. The best way to describe The Empty Man is as a kind of psychic cancer; a virus of the mind that erodes your sensibilities by overloading them with visions and sounds and commands. You might think your spine is trying to kill you or that your next-door neighbor wants you to eat their skin.

There's not much left to say about The Empty Man without giving out spoilers, but it goes without saying that the disease's origins and the identity of Patient Zero in Dunn and Del Rey's thriller will no doubt leave our readers stunned.

4 I-Pollen Degenerative Disorder

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The America of Ellis and Robertson's "Transmetropolitan" is basically one of the worst visions of America's future we can think of, with people snorting dead celebrities like cocaine and time travellers wandering the streets homeless, alone and forgotten. As expected, whatever illnesses emerge out of this landscape must be some suitably horrible stuff.

While lacking an official name, I-Pollen Degenerative Disorder comes as a result of using a piece of technology called Information Pollen or I-Pollen. I-Pollen is a type of dust that used to transmit information between whoever is exposed to it. While this piece of tech sounds really neat and convenient, there's a reason why it's been outlawed: it has a chance of permanently destroying your brain.

The actual disease itself is described as being like a combination of Alzheimer's disease and Parkinson's. Anyone who develops this disease should expect their motor and cognitive functions to eventually shut right down -- unless you're part of the meagre 1% of the population who can resist its effects.

3 S.T.O.R.M.S.

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The last STD we're going to cover on this list is probably the worst one we can think of, and it comes to us from the morbidly-fascinating mind of Alan Moore himself, so you know you're in for a ride.

The disease is found in the book "Top 10," written by Moore and drawn by Gene Ha and Zander Cannon. Short for Sexually-Transmitted Organic Rapid Mutation Syndrome, STORMS is the last remaining disease found in Neopolis, a city-state populated entirely by super-powered, mystical or cybernetically-enhanced people. STORMS is a disease that came about through years and years of inter-species mixing, a viral cocktail birthed by one too many bareback sessions with aliens and gods. It changes one's physiology in its later stages, to the point that the infected cannot support their own organs and die a horribly mutated mess of limbs and teeth.

Needless to say, if you're planning on cruising through Neopolis, and you don't want to look like something found in one of H.R. Giger's absinthe dreams, then you better bring some protection with you.

2 The Walking Death

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Zombie viruses come and go in popular media, but Robert Kirkman demonstrates his love of the genre in his monolithic undead-apocalypse yarn "The Walking Dead" perfectly. What makes the disease that produces the Walkers stand out (and this is a SPOILER if ever there was one) is the fact that you don't necessarily have to be bitten by a zombie to become one. In fact, there's one pivotal scene later on where a character is killed off by natural causes and rises from the dead moments later.

The implications alone are huge here. Either something else is afoot, or everyone in "The Walking Dead" has the disease already!  Kirkman revealed that he wasn't going to stop writing "TWD" until he got bored of it, but this a pretty big ball to drop on our heroes. Does this mean there's any cure for the disease, even when someone's a shambling abomination? Or does this mean that the preacher at every funeral now has to come equipped with a twelve-gauge shotgun?

1 The Jigsaw Disease

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Last on our list is probably the worst disease you can catch, and it comes from a dystopian world that makes the United States of "Prez" and "Transmetropolitan" look like a trip to Wonderland. We're talking about the 2000AD world of "Judge Dredd."

Like everything else in the surreal "Judge Dredd" universe, the Jigsaw Disease is nothing to mess with. A wasting illness, the Jigsaw Disease is called such because the people who catch it start to disappear piece by piece. We don't just mean that a piece of your ear will vanish or you might wake up without a nostril. No, we mean that you could wake up one morning and part of your skull might be gone or there's a big circular hole in your torso where your stomach used to be. This is a disease so terrifying that the only known way to treat it is with a special drug that actually accelerates the symptoms and makes the host die faster.

Did we miss any iconic comic book diseases, or did we catch them all? Spread your knowledge in the comments!