Exceptionally lethal pathogen that kills everything it touches.

Plague Type:


Special Ability:

Gene Compression
Deactivated Modified Genes
Nucleic Acid Neutralization
Unlock Annihilate Gene


Complete Nano-Virus (Normal or higher) or $0.99USD

Release date:

May 23, 2012, Version 1.0

Core Stats:

Infectivity: 4 Severity: 1 Lethality: 0 Cure Requirement: 118% Mutation: 0.5

Base Cross Country Transmission:

Air: 1 Sea: 1 Land: 1

Base Environmental Effectivity:

Wealthy: 0.4 Poor: 1 Urban: 1 Rural: 1 Hot: 0.1 Cold: 0.1 Humid: 1 Arid: 1

The Bio-Weapon is a genetically and biologically engineered and modified virus that was accidentally released from a laboratory. It is the final Standard Plague available in the game. It is quite similar to other diseases, primarily the virus standard plague type in physical appearance and in shape and size. However, unlike the previous plague types, the Bio-Weapon will grow progressively more lethal over the course of the game, making it more likely to kill off one's hosts before they are able to infect more people and causing quick detection. To win, the player must use the disease's special abilities to lower the lethality in order to avoid killing too many hosts too early. This quirk makes the Bio-Weapon ideal for speed run strategies, similar to Nano-Virus (cure starts at the beginning of the game). The interface of the Bio-Weapon also very strongly resembles an RNA Retrovirus.

By default, the Bio-Weapon has slightly higher infectivity than usual, and is better suited to rich countries than average.

Special AbilitiesEdit

Gradual LethalityEdit

Every in game day, the game will roll a random chance for the Bio-Weapon to increase lethality naturally. As the game progresses, the chance of lethality will increase exponentially. Nucleic Acid Neutralization will reset the exponential growth rate to zero, Gene Compression reduces lethality growth, Deactivate Modified Genes removes set amounts of lethality.


For strategies, tips, and Q&A, please see Bio Weapon Strategy Guides.

Stages of Evolution Edit


Real Life ExplanationEdit

True OriginsEdit

The Bio-Weapon in the game does not show what species of microorganism it is. In real life, biological weapons do exist in the form of biological agents. We already have Bacillus anthracis or Anthrax and even a rumored hybrid smallpox-ebola bioweapon made by Russia (it is still unknown whether it really exist,some dismissed it as a Russophobic propaganda).However,the bio-weapon in game looks more like a typical genetic-engineered virus.This is because it looks like a typical design of a virus which consists of a sphere with spikes sticking out on all sides.

How does it kill?Edit

In the game, the bio weapon will increase its lethality overtime to kill victims even if there is no lethal symptoms developed. This has made the pathogen to be the second most mysterious pathogen in the game as its killing mechanism does not show any signs until death arrives. One of the possibilities of the killing mechanism is by emitting toxins on the infected as evidenced on several abilities that limit or delay lethality progression. The most possible toxins that it produces are Botulinum Toxin or Tetrodotoxin. Botulinum Toxin, the world's most potent toxin, can cause weakness on mouth, eyes, arms, chest muscles and legs. Eventually, it will weaken the diaphragm, causing breathing difficulties and lead to death by respiratory failure that comprise the balance of oxygen and carbon dioxide in the body by reducing movement of respiration muscles, which is fatal as the brain could not get enough oxygen to keep functioning. Alternatively, Botulinum Toxin can also cause arrhythmia and lethal cardiac arrest. For Tetrodotoxin, it can cause serious human ability impairments including shortness of breath and paralysis. Death will occur when the toxin immobiles diaphragm at least 30 minutes after the victim is completely paralyzed. It's Annihilate Gene is even mysterious: It only unleashes the pathogen's fury without stating the cause of death. The closest explanation is the bio-weapon will produce multiple copies of it when infecting human cells and aggressively destroy the said human cells once the masses of bio-weapons started to release into every direction, searching for new cells. In other words, it can shut down organs rapidly, similar to Total Organ Failure, but in a fast way without giving too much attention (Affected victims might show symptoms that are caused by the shutdown of an organ/system such as heart attacks, sudden coma, instant paralysis and rapid asphyxia) before rapid deaths.

Trivia Edit

  • Possible real-world Bio-Weapons include smallpox, Black Death, Ebola, or even rabbit fever. Anthrax is also a possibility.
  • If one assumes a symbiotic relationship is the most logical end of evolution, the Bio-Weapon is the disease type most prone to extinction because it kills its hosts quickly, sometimes before they can infect other people. This is due to the fact that with real-life diseases, there is a trade-off between infection spread and lethality.
  • Interestingly, its image is only a biohazard sign (the signature logo for Plague Inc.), directly opposed to other plagues, which have an image to explicitly introduce themselves. This is likely because other plague types (such as virus and bacteria) are able to become a bio-weapon, though the in-game Bio-weapon is more reminiscent of a type of engineered virus.
    • The icon has been updated, however, and now it resembles that of the Virus instead.
Standard Plague Types


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