This achievement is officially known as the Patient Who? Achievement. In every Plague Inc, Evolved guide and walkthrough that I have studied, it is always listed as a random occurance whose triggering mechanism is unknown. I am about to prove that this is no longer true!

The object of the Achievement is to stop the CDC from locating Patient Zero - the person who began the Plague that is threatening to destroy the world. The object of this guide is to force the circumstances that bring the CDC into the picture to begin their search

I have run this scenario so many times now since I stumbled across the correct combinations and sequences while trying for a different achievement M9A1 Gernsback's Plague In Space Guide and accidentally changing the order of some things, that I now feel confident enough to say that if you follow every single step that I list in the exact order in which they are listed, that you will get the Patient Zero achievement on your very first try - both in Evolved and in the mobile version of the game.

You also need to be prepared to play a very long game that will net you a very low score at the end - 3 Biohazards means you've played very well. You'll also have to think for yourself and manage the cure rate when it gets into stratospherically high, turn your hair white levels, while making sure that once you've lured the CDC into thinking that they're close to their goal, you are careful not to be too lethal too quickly, or you can still lose the whole enchilada!

As an added bonus, if you don't already have this one, you may also get the opportunity to gain the Touchscreen Trash Achievement during this same game.

Now...let's begin the steps to gaining this most mysterious of achievements!!

Begin with Prion - I recommend playing it on Casual. I have played on Normal difficulty, but it can be hair-raising enough watching your cure climb to 90% on Casual without the added stress of having the damn doctors working even harder!





Catalytic Switch - you're going to need the DNA from all of those cure bubbles you'll be popping.

Genetic Mimic - don't make it any easier on them than you have to!

I have Aquacyte selected in the picture above, but experimented further and found that using Native Biome sometimes worked just as well if not better. Your choice.

Urbophile - You'll understand why in a minute.

Sympto-Stasis - DO NOT try this with something else - you'll lose!

We're going against all the conventional wisdom on this one - mainly because doing so may be part of why it works! and so we'll be starting our Plague in the USA!! It IS where the CDC is headquartered, after all!



Don't worry - it'll be ok. Saudi Arabia and India will still be there for your next games.

Ok gamers and gamerettes...this is where you have to follow things exactly. A single deviation in the order of buying your first few traits will send the CDC back into hiding. So, as soon as you develop enough DNA for each trait, go ahead and purchase it separately so your disease will spread quickly and earn you enough DNA when you get to the important stuff.

1. Drug Resistence 1
   
2. Air 1
   
3. Air 2
   
4. Water 1
   
5. Cold 1
   
6. Drug Resistence 2

Also be sure to DEVOLVE ANY SYMPTOMS that try to sneak their way into your game until you're ready for them.


These aren't as important to do as quickly as the first set, and I'm not certain that the order is quite as important, but you'll still want to get them out of the way quickly and give your DNA plenty of time to build back up before the world is infected and it's time to start buying symptoms. This is the order that I go by.

• Neural Atrophy 1, 2 & 3
  
• Genetic Hardening 1 & 2

At this point your Transmission and Abilities boards should look like this:




Now, sit back and wait and keep devolving symptoms until the entire world is infected.

OK - it may have taken awhile, but everyone in the world is infected. In none of my runthroughs have I ever had Greenland or an island fail to be infected. If this should happen to you, my advice would be to just chuck the game and start again rather than mucking about with Transmission traits that might end up screwing the pooch in the end.

Also, you don't need to wait for the "There are no healthy people left" popup, as for some reason it occasionally fails to appear until very very late in the game. Just watch your numbers, check your world map, and you'll know when there are no healthy people left.

At this point you should have between 80 and 100 DNA points banked. If you don't, just sit and pop orange bubbles and devolve symptoms until you have that minimum of 80. This is NOT the place when you want to run short on DNA!


When everyone's infected and your DNA is up to par, evolve all of the first and second tier symptoms in no specific order:

The following is the reason you needed to be certain of having enough DNA when you reached this level in your game. As soon as you evolve all of your first and second tier symptoms:

Evolve Seizures
Evolve Insanity
IMMEDIATELY DEVOLVE SEIZURES

The above Symptoms will make your Plague severe enough to be noticed and taken seriously enough to cause worldwide health measures, cure efforts, and most importantly for our objective here, investigation. But by devolving Seizures, you removed the only Symptom that has any Lethality, which will lower the governmental pucker factor enough to keep them from throwing all their resources into an immediate all-out cure effort, while still frightening them enough to take us seriously.

Now comes the hardest part of the entire game. After you finish evolving all of the above symptoms and your Symptoms screen looks like this


you go back to your game screen, watch as your Plague is discovered by the world....and you sit and wait....

Before I say anything else, let me be sure to mention that even though your Plague is now symptomatic, they are still very specific symptoms. This means that during this waiting period, while you're watching the cure rate seem to skyrocket and the news ticker is getting more serious by the day...you still need to devolve any symptom that tries to sneak its way in and mess with your plans for outwitting the government.


Many of you may already have this one, so it won't matter to you that it may happen, but you still need to make the effort to overcome it anyway if it does, since it may effect the rest of the game.
Touchscreen Trash
At some point you may get a popup saying that there is an ICure in developement, and to watch for future distribution of the device. If you do, at that point you do nothing but continue to wait, start popping your blue bubbles if the researches have hit cabin fever mode and started zipping around the globe, and keep devolving symptoms.
I should warn you that if it does happen, it could be as early as 30-40% cure rate, or at 70% or even later! (I told you this could be nerve-wracking!)

You may even get the first CDC popup before you get the first ICure one, or in between the first and second one. At any rate...

When/If you get the popup saying that the ICure device is complete and is to be distributed worldwide, it's time to play a little joke on them, because since sweating is already evolved we should be powerless to make the silly thing fail, right?
Leave the popup on your screen and go into your Symptoms screen.
Devolve sweating.
Immediately Evolve sweating again!
Now go back to your game screen and dismiss the ICure popup.
Voila! They may take awhile to tell you about it, but you just foiled their little ICure device, and, if you needed it, you bagged yourself another Achievement!

Now go back to waiting and devolving symptoms...

You have followed all of the preceding instructions to the letter, waiting patiently as the cure rises higher and higher, wondering if the government is EVER going to do their damn jobs!

When your cure rate gets to 80% no matter what has or hasn't happened yet, Evolve Genetic Reshuffle 1 & 2 and drop it back down to 70% This frustrates researchers and pushes them harder into realizing they need an alternative - like finding the schmuck who started this whole mess to begin with!

Finally they get off their butts and the following appears



"CDC Teams Hunt Patient Zero"

(You might want to save your game at this point, just to be safe)

You still have nothing to do but wait, bubble pop, devolve, and deal with the ICure if it shows up during this period.

Eventually - and it may be VERY eventually - I have had this happen literally when the cure was at 98% - you will get THIS popup



"CDC Teams close on Patient Zero "

FINALLY!! It's time to take them down and show them who's REALLY the boss of this game!

While the popup is still on the screen
Evolve

• Skin Lesions
  
• Necrosis
  
• Dysentary

If your cure rate is very very high and you've already panicked and used your final Genetic Reshuffle, you can also Evolve Paralysis and Coma.

What you have to be careful to watch for is people to begin dying very very fast, which is why I try to avoid evolving the last two symptoms unless there's really no choice. If you kill off so many people that there aren't enough researchers left to care about Patient Zero, or if most of the USA is already dead, then you can still fail to get the achievement. So manage not just the cure rate, but the lethality as well. Remember that once a lethal combo is unlocked, you can't stop its progress even if you devolve the symptoms that led to it. This is where skill and game-play experience are the most important.

It seems redundant to say at this point, but you STILL want to devolve any lethal symptoms that pop up until you see the following




"CDC fail to identify Patient Zero"

And WOOHOO! You just earned the elusive "Patient Who?" Achievement!


You've gotten the Acheivement, win or lose. But if you still want to win purely on principle (or because you're a competitve OCD nut like me who can't stand to be defeated), take all of your remaining DNA and buy all of the deadliest symptoms that you can afford, beginning with Total Organ Failure and working your way down the list until you literally have evolved every symptom on the whole board (unless there's one that scientists "gained understanding of" earllier in the game - evolving that will really speed up the cure!).

I have started killing people off in a serious way when the cure was at 99% and the disease had been running for 2800 days, and still won my game. Your points may be in the four digit range. But you weren't playing this for the Biohazards or a fake leaderboard score. Winning is just the icing on your Plague cake after gaining an achievement that we've all thought was random chance until just now.


I apologize for my overly wordy walkthrough, with its miles of explanation. But this was such a toughy, and I'm a little proud of myself for sticking with it until I was sure that I had it right. Please let me know if it worked for you, and, more importantly, if you KNOW that you followed every step exactly, did it two or three times and it still didn't work - PLEASE let me know about that immediately!!

For now, good luck, good gaming, and goodnight!! This one was a bugbear!

Oh - and BTW - if you used this guide and it worked for you, I'd be grateful if you'd give it a thumbs up as a show of your appreciation! Everybody likes to know that their work is appreciated. :-)