Plague Inc. Bacteria Mega-Brutal Guide/Strategy | Mutation 10 | 5 Biohazards | Below 365 days

Because of the release of mutation 10, some basic plagues have been re-worked and changed, making the past mega-brutal guides I've made somewhat obsolete. So here I am making brand new mega-brutal guides for the basic plagues.

I've played around with Bacteria in mega-brutal for a few games and found that starting in Saudi Arabia and focusing on symptoms early on will make your infectious-journey a wee bit easier. Saudi Arabia connects to almost every rich country and Iceland as well. Making it a very good country to start in.

I recommend you guys to play around with this strategy, you might even get a higher score than I did. There's also a lot of factors that affect the game overall, so be prepared to change things up if necessary. Events like Ship Sanitation, Watchlist placements, and awareness days heavily affect the success of this strategy, because these events will cause faster harbor-and-airport closures and boosted cure speeds.

So let's get started.


  • ATP Boost - The 8 DNA start will be extremely helpful and I really love this gene.
  • Aerocyte - Because Saudi Arabia has a lot of country connections through planes
  • Sympto-Stasis - Helps us be able to evolve multiple symptoms without the fear of insane DNA prices.
  • Genetic Mimic - Slows down the cure. Lower cure progression equal higher score, my friend.
  • Extremophile - Because...minor bonus
TIP: Be sure to devolve mutated symptoms, but only to a maximum of 3 times. The 4th one will cost DNA and we don't want that. You could also make a judgement call whether the mutated symptom would be of help or just a liability, but I recommend just devolving a mutated symptom.

1.) Start your Bacteria in Saudi Arabia. Pop the first red bubble then evolve the following in this order:
  • Air 1
  • Coughing
  • Sneezing
  • Cysts
  • Abscesses
  • Hyper-sensitivity
  • Rash
  • Sweating
Having these symptoms will increase infectivity at a decent rate, although the world will detect our Bacteria sooner. Don't worry about that, we'll finish this fast.

2.) Continue evolving the following in this order:
  • Air 2
  • Water 1
  • Pneumonia
  • Pulmonary Oedema
  • Diarrhoea TIP: This symptom and Pulmonary Oedema can also be evolved after evolving Cold Resistance 1 & 2.
  • Drug Resistance 1
  • Cold Resistance 1 & 2
  • Water 2
  • Extreme Bioaerosol TIP: You could also opt to evolve this after Necrosis
At this point in the game, you might already be detected. Again, don't worry, It'll all be over soon.

3.) We're almost there. Evolve the following:
  • Skin Lesions
  • Necrosis
  • Drug Resistance 2
  • Paralysis
  • Coma
  • Total Organ Failure
  • Insomnia
  • Paranoia
  • Seizures
  • Insanity
The following symptoms will make our Bacteria lethal and at the same time cure-slowing.

4.) From this point on, it's all about effective plague management. There's plenty of ways to go about this part, this is what I did
  • Evolve: Nausea
  • Vomiting
  • Dysentery
  • Pulmonary Fibrosis
These symptoms will increase overall infectivity and will make the game end faster, if you're aiming for that fast finish. 

If the cure progression gets to, or above, 25%, consider using Genetic Re-Shuffle 1.

You could wait for the entire world to be infected, if you're being safe, or evolve additional lethal symptoms right away. I recommend waiting until every country is completely red(infected). Evolve these symptoms once the world is completely infected:
  • Hemorrhagic Shock
  • Internal Haemorrhaging
  • Systemic Infection
  • Tumours
Having all these symptoms including Total Organ Failure and Dysentery will make the kill rate extremely fast that Necrosis won't be able to catch up, so be sure to have the world almost completely infected before evolving them.

If you think your cure progression is too high, consider evolving some more Genetic Re-Shuffles instead of the last 3 lethal symptoms above. Hemorrhagic Shock combined with Total Organ Failure is enough to make a decent kill rate.

So there you have it. Using this strategy, I was able to get these scores in 4 games.

As you can see, the cure progress affects the final score a lot. So having the cure progression below 30% will make for a higher score. My 321-day finish has a higher score than my 312-day one, simply because the cure progress was higher on the latter.

Thanks for reading, and I hope this guide has helped you finish Bacteria Mega-Brutal with a 5 Biohazard score. Happy Spicy Gaming, everyone!


  1. This is a bit hard for me... Like really, I get the whole word infected and turn on lethality when I notice that Greenland is NOT infected! >:O

  2. The cure got to 32% but still 5 biohazards!

  3. Here's my playthrough with 5 biohazards

  4. Idk what I'm doing wrong but I've tried this 5 times and it isn't working for me, I don't even get half the country infected before they already have the cure at like 70%. I'm so frustrated, help!

  5. Did this 4 times...either Greenland or Iceland stays healthy