Plague Inc. Artificial Organs Scenario: Prion Mega-Brutal(3 Biohazard) Guide & Walkthrough

The Prion plague type is one of the seven available plagues that can be used to finish the Artificial Organs Scenario. If you'd prefer to finish this scenario with a different plague..

Click Here for the available plague guides.

In my opinion, this might be the easiest plague to use in order to achieve a 3 biohazard score. Although the Prion takes quite some time before an evolution takes effect, this unique trait actually compliments the strategy we're about to use.

You won't have to worry about the important pop-up events that should appear in this scenario since this guide was built in a way that both these pop-ups will appear every time. I've used this strategy in 3 games, all of which finished with a 3 biohazard score. The average game stats were finishing within 310-350 days with a cure completion of 10~20%.

There's not much to warn about since this guide works so well(for me, atleast). Genetic Shifts will always be a problem in mega-brutal difficulty, it's the only thing I could think of that affects the success of this strategy. Now let's proceed to the guide.

Gene Setup:

  • ATP Boost
  • Aquacyte
  • Sympto-Stasis
  • Genetic Mimic
  • Extremophile

1.) Before selecting a country to start in, evolve Cysts, Abscesses, and Coughing.

2.) Start in China then continue to evolve the following symptoms as soon as you have the DNA to do so:
  • Hyper Sensitivity
  • Pneumonia
  • Coughing
  • Rash
  • Sweating
  • Skin Lesions
Reminder: Devolve any symptom that mutates. Throughout the entire game, you'll only have to do this once.

3.) Continue to evolve symptoms, transmissions, and abilities in this order:
  • Water 1 & 2
  • Necrosis
  • Inflammation
  • Seizures
  • Drug Resistance 1 & 2
  • Insanity
During and after this step, both pop-ups should appear. The first one appears shortly after evolving Necrosis, and the second appears after evolving Insanity.

4.) Onto the next set of evolutions:
  • Cold and Heat Resistance 1 & 2
  • Environmental Hardening
  • Air 1 & 2
  • Extreme Bioaerosol

5.) At this point, we'll need to wait until the entire world is infected. After the appearance of the pop-up, evolve the following:
  • Paralysis
  • Coma
  • Total Organ Failure
  • Hemorrhagic Shock
  • Systemic Infection

6.) After evolving everything above, use your remaining DNA to evolve all three Genetic Re-Shuffles. 

At this stage, all your waiting for is the complete eradication of humanity - so much for their artificial organs. 
In order to get a 3 biohazard score, you'll need to finish within 360 days with a cure completion below 60%.

I hope this guide has helped you get those 3 golden biohazards, if you've got any questions or something you'd like to share post them at the comments below. Thanks for reading this guide and Happy Spicy Gaming!


  1. Worked 1-2 tries :)

  2. This comment has been removed by the author.

  3. My plague killed all the hosts before infect the world. Happened 2/2 times. Could not infect Greenland.

  4. Now I was able to do it, after Paralysis, I waited until Greenland was infected. Then I proceed with the deadly symptoms

  5. Excellent advice. Beat Mega-Brutal in 331 days with a 16% cure. I actually had to devolve some of the fatal symptoms for a while to let Morocco catch up. Didn't even need the Genetic Re-Shuffle (although I used one to drag the cure down to the 16%).

  6. HowToLoose1hourForNothingApril 20, 2015 at 5:40 AM

    3 tries. Following every step as it said. Never finish under 400~440 days and 60~63%.... And it's supposed to be the easiest ?...

  7. HowToLoose1hourForNothingApril 20, 2015 at 7:02 AM

    Ok, so your Prion strategy, for some reason (raised difficulty on PC version ?...) is a 0% chance of winning (on 10 attempt, 0 success).

    But to whoever playing on PC and trying this beat Mega-Brutal achievement, go on the Virus strategy instead. Despite what "Yo it's Spicy" say, it's far more difficult with Prion than with Virus.

    "There's not much to warn about since this guide works so well(for me, atleast)" <---- and no, no it doesn't... (at least for the entire population playing on PC unless very lucky).

    Go on the Virus strategy everyone, thousand of time more chance of success..

    But seeing how "Spicy" is positive about his own Prion guide, I really believe Prion's difficulty has been raised since when this guide here was writing. Either this, or author should stop smoking weed lol, because you can't go under 400 days on PC version with this strategy here.

    Thanks anyway.