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FEV Curling-13[1] was a viral agent tailored to reach maximum levels of lethality with minimal exposure levels required to achieve the result. Based on the original FEV-II recovered by the Enclave at Mariposa Military Base's ruins, it was developed under the direction of Lt. Col. Dr. Charles Curling of the Chemical Corps from 2236, to provide the means for the Enclave's second holocaust. Trials would progress for several years, culminating with the thirteenth trial where the biological weapon would be perfected for use on civilian populations.[1]


The Enclave FEV Project was ultimately developed to rid the entire world of human-based mutants, regardless of the degree of mutation. Any person that wasn't inoculated from the virus would die several hours after contact. The Enclave's plan was to release the Curling-13 virus into the air and let the Earth's jet streams takes care of transmission; given enough time it was projected these air currents would carried the virus across the world. Enclave President Dick Richardson did not take joy in exterminating all mutated humans (or non-mutated humans) but believed the deployment of Curling-13 to be the last, best hope for humanity.[2] Before the virus was able to be deployed, the Chosen One destroyed Control Station ENCLAVE and the virus with it, mere hours before it was scheduled to be released.[3]


Unlike FEV-II, which required a severe overdose and low radiation count in the subject to work correctly, Curling-13 killed indiscriminately. Just a .0001% aerosol solution exposure was enough to kill Arroyo villagers in under one hour, as massive hemorrhaging and inflammations start, leading to a complete failure of the victim's organs within sixty minutes. Significant radiation-induced mutation may thus be beneficial - humans with a lower radiation count suffer a much worse fate. Pure Vault 13 dwellers and potentially Enclave citizens exposed to the virus first had an onset of symptoms, including a burning throat, heartburn, followed by a feeling of burning lungs, drowsiness, and loss of sight.[4] Within 60 minutes of exposure, they'd suffer subdermal hemorrhaging and convulsions, with the agony lasting 14.5 hours on average. No test subject survived the tests on Control Station ENCLAVE.[1]

Despite chemical supplies necessary for production of the virus running low[5] the Enclave's potential manufacturing capacity was tremendous. Their production estimates were that they could produce 250,000 gallons of the virus within six weeks. Projections of its deployment suggested that the winds would then carry the virus worldwide, achieving global saturation in two weeks.[1] Only humans and human-based mutants would be eradicated, however - FEV was engineered to bond only with human glycoproteins, leaving other animals and plant life alive. The virus, if released as planned, would have eventually exhausted its potential hosts and essentially self-destructed.[6][7]

Well before Dr. Brian Virgil developed his FEV cure, FEV Curling-13 was the first known FEV strain to have a medical treatment developed in the form of an inoculation that granted total immunity from its effects.[8] Production of this inoculation was completed around the same time as the virus was ready for release, but had not been distributed to every Enclave member at the time of Control Station ENCLAVE's destruction.[9]


Main article: Modified FEV

While FEV Curling-13 was never deployed, the progress made in turning FEV into a lethal biological weapon by the Enclave on the West Coast would later be continued by the Enclave on the East Coast.[10] A modified strain of the Forced Evolutionary Virus developed by John Henry Eden, based on the earlier FEV Curling-13 strain, only now it was designed to be placed into the Project Purity water purification system.[10] According to President Eden it would have eradicated super mutants, ghouls, and all other "unclean" citizens, which was anyone who had been born in the Wastelands and exposed to radiation and other mutational effects from birth.[11] The only populations who would be able to drink water contaminated with this strain safely were those free of mutations, such as the Enclave and humans who were born in sealed Vaults.[12] This strain of FEV was less lethal than Curling-13, and required ingestion of it through infected water supplies. Even then it did not kill immediately and required ingestion of large quantities of contaminated water.[13]


FEV Curling-13 is mentioned in Fallout 2 and indirectly mentioned in Fallout 3.


  1. 1.0 1.1 1.2 1.3 The Project
  2. Dick Richardson: "{236}{prs40a}{The only way for true humans, and democracy, to be safe is to cleanse the mutants from the globe. We humans will take back that which is rightfully ours.}"
    The Chosen One: "{239}{}{Cleanse the mutants? That sounds a bit drastic. How are you going to do that?}"
    Dick Richardson: "{240}{prs41}{We found a research facility in operational shape about 70 years ago. A former military base that had been used to research a special virus.}"
    The Chosen One: "{241}{}{A virus?}"
    Dick Richardson: "{242}{prs42}{Yes, the F.E.V. virus. It was originally developed to turn soldiers into super-warriors but it failed. The warriors were tough and strong, but far too stupid. However, our brilliant Chemical Corps altered it.}"
    The Chosen One: {243}{}{Altered the virus? Why?}"
    Dick Richardson: "{244}{prs43}{To turn it into a staggeringly effective killer. Any humanoid that isn't inoculated against its effects before its release, will die. That is the Project.}"
    The Chosen One: "{245}{}{That's insane.}"
    Dick Richardson: "{246}{prs43a}{No, no. That's humanity's last, best, hope. That's what we've been working towards all these years.}"
    The Chosen One: "{247}{}{Great, so you have all this poison and no way to spread it around.}"
    Dick Richardson: "{256}{prs47}{Oh, but that's one of the advantages of the F.E.V. virus. We can release it right here and the jetstream will carry it worldwide. It'll have plenty of time to cleanse every nook and cranny of the globe.}"
    The Chosen One: "{257}{}{OK. Then why did you have to kidnap my villagers and the people from Vault 13?}"
    Dick Richardson: "{258}{prs48}{Test subjects. Your villagers are all descended from vault stock and we had to make sure that the F.E.V. toxin was still effective. The subjects from Vault 13 test that and an inoculation against the FEV.}"
    The Chosen One: "{259}{}{You're not testing the inoculation on my people?}"
    Dick Richardson: "{260}{prs48a}{It's hardly necessary. I'm sure we could and it would work, but there's no reason to do so.}"
    "{261}{}{Did it ever occur to you that what you're doing is wrong?}"
    Dick Richardson: "{262}{prs49}{Never. Part of the president's job is to make the tough decisions. A lot of near-humans will sacrifice their lives for the return of humanity. Humans will prevail.}"
    The Chosen One: "{264}{}{Just because everyone out there doesn't have an exact copy of your DNA that doesn't give you a license to exterminate them.}"
    Dick Richardson: "{267}{prs51}{Oh, I don't relish this decision. If there was another way- but there isn't. No price is too high for the survival of the human race. If you were human, you'd feel the same way.}"
  3. Dick Richardson: "{265}{prs50}{You can't stop it. The tests are complete and the toxin is ready for release. In hours, your villagers will be the first to make the ultimate sacrifice. The other mutants will follow. An unfortunate footnote in the continuing history of the human race.}"
  4. Enclave citizen: "{123}{}{Where's my breather mask?}"
    "{124}{}{Something smells funny.}"
    "{125}{}{I don't feel too good.}"
    "{126}{}{The air burns my throat.}"
    "{127}{}{Man, do I have some nasty heartburn.}"
    "{128}{}{My lungs are on fire.}"
    "{129}{}{I think I need a breathe of fresh air.}"
    "{130}{}{Is it getting darker in here?}"
    "{131}{}{So sleepy, must rest.}"
    "132}{}{I think I'll just sit down for a bit.}"
  5. Dick Richardson: "{248}{prs44}{We've run short of certain critical chemicals. We can get them from the drug labs of New Reno. If the mutant-mobsters use our guns to kill each other, just saves us the trouble.}"
  6. The Chosen One: "{209}{}{I still don't understand how that's *perfect.*}"
    Charles Curling: "{211}{}{The F.E.V. toxin will only attack to humans, leaving everything else alive, better still, within a month all the mutants will be dead and the F.E.V. toxin will die out as soon as it runs out of hosts. }"
  7. The Chosen One: "{203}{}{Great for you, but how does that have anything to do with eradicating everyone?} "
    Charles Curling:
    "{204}{}{Oh, yes, well, I was getting to that….The F.E.V. virus bond is species specific, it will only bond with human glyco-proteins. It only took a few years to tweak the F.E.V. virus to make it more lethal than it all ready was. The result was just what the doctor ordered, perfect in every way. }"
  8. The Chosen One: "{237}{}{What about my people? Or me? Or you, for that matter?}"
    Charles Curling: "{238}{}{I can release the antidote into the air-system for all the cells. The detention level is served by a separate air system from the rest of the Enclave. Everyone will think that I'm just running another test. You, I can inoculate directly, here and now. (he reaches for you with a syringe)}"
  9. Dick Richardson: "{273}{prs54}{You could try, I suppose, but soon the staff of the Enclave and Navarro will be inoculated.}"
    Chosen One: "{274}{}{They aren't already?}"
    Dick Richardson: "{275}{prs55}{We just have to distribute the supplies. A matter of hours. Besides, the Enclave is a sealed unit. No air or contaminants get in or get out.}"
  10. 10.0 10.1 The Lone Wanderer: "Where did this plan of yours come from?"
    John Henry Eden: "A great many years ago, the remnants of the government had a similar idea. I can only assume the plan failed, as I never heard word of its success. But the plan itself was sound. I've made a few modifications, and with your help, I do believe it can work. There's a bright future ahead of us, my young friend."
    (John Henry Eden's dialogue)
  11. The Lone Wanderer: "Say whatever it is you have to say."
    John Henry Eden: "Our land is ravaged by mutation. The war was so many years ago, and yet we still suffer from its effects. We cannot move forward until humanity can gain a solid foothold in the world. To do so, we must rid ourselves of the mutations that have plagued us for so long. These "Super Mutants", Ghouls, hideous creatures... I believe your father's work can do that in a way unlike any other."
    (John Henry Eden's dialogue)
  12. The Lone Wanderer: "Won't this kill pretty much everyone in the Wasteland?"
    John Henry Eden: "Anyone or anything that has been affected by mutation will be eliminated. You will likely be immune, thanks to your upbringing in the vault. Likewise, the good people of the Enclave will be unaffected as well. I understand that you may have become sympathetic to certain individuals in your travels. Individuals this will eliminate. Please recognize that the fate of our entire country rests on this plan. Sacrifices must be made for the greater good."
    (John Henry Eden's dialogue)
  13. The Lone Wanderer, who having been born in the wasteland is susceptible to the modified FEV; can drink 3 bottles of infected Aqua Pura before it kills them.