Plague Inc. Wiki
Plague Inc. Wiki
Neurax Worm
The logo of the Neurax Worm expansion pack

Plague Type:


Special Ability:

Trojan Planes


Complete all Standard Plagues (Brutal or Mega-Brutal) or $2.99USD (IOS)
Complete Fungus on Normal (PC)

Release date:

July 15, 2012, Version 1.3 (IOS)
Version 0.5.0, February 20, 2014 (Plague Inc. Evolved)

Manipulative organism that burrows into the brain.

The Neurax Worm is a plague type that was added in Mutation 3 or version 1.3 (August 30, 2012). It is a manipulative parasite that burrows into the host's brain and has the ability to exercise mind control.

The Neurax Worm has two different ways to win. In addition to just simply killing everyone and wiping out humanity (which will unlock the Worm Food achievement) the Neurax Worm can also enslave humanity and force them to worship it through the Transcendence symptom.


The Neurax Worm is a special disease type which was awakened from its millennia-long slumber by human activity. Its defining trait is the ability to burrow into the host's brain and exercise inner mind control from there. It's available for purchase it for $2.99 USD or by beating all disease types on Brutal difficulty (mobile) or beating the Fungus disease on Normal or higher (PC).

The Neurax Worm is also the scenario template in a scenario called Santa's Little Helper, where the world has turned into a dark and gloomy dystopia. Land borders, airports and seaports have been shut down to reduce people's happiness down to zero. People are forced to wear grey clothing, and holidays, laughter and any other form of Joy have been made illegal. The player must play as the Neurax Worm and make everyone happy again.

In Reality


The Neurax Worm is essentially a parasite. It is different because it is girthier and shorter in length. Its body length is about as small as a bacteria in nymph form and almost the vertical length of the brain viewed from above. The height of the worm, however, is still unknown because there is only a small space between the brain and the skull which might not fit the worms gigantic body (it is more likely as tall as a ping-pong ball or a hockey puck). In the brain, it grows tendrils, encircling the host brain to feed off the nutrients carried by the brain's blood vessels. At the same time, the tendrils also act as "foreign neurons". The tendrils will either transmit impulses from neuron to neuron or impulses emitted from the worm to the brain. This often affect the normal activity of the impulse transport, causing mental illness.

In the game, the worm can survive outside and "move" around to spread infection. It is within reason that the worm would lay eggs outside, and be carried around by mediums. Severity would be increased by some transmissions, because it could make the worms bigger. The eggs would be ingested and the worm hatches and makes its way up the tunnels of the body.

In real life, a lot of "mind control parasites" exist in real life, and they send their hosts to a certain place to be killed, for more spreading by the host's corpse being consumed with the young their dead host. Moreover, parasites in real life don't live that long. This explains why there are symptoms that encourage the host to spread the worm as well as the existence of the "Suicide" symptom.

Last Resort Cure

Neurological surgery would be the best cure, because it can be removed surgically as it is not very small. However, its tendrils would lead to extreme caution being needed to perform an operation. Once the worm is removed, the patient would have regular radiotherapy sessions to kill off eggs and nymphs still present.

The Neurax Worm starts with three unique transmission options: Concertina Locomotion, Eggs, and Genetic Swap. Concertina Locomotion and then Undulatory Locomotion must be taken before Air and Water transmission are unlocked; Eggs must be taken to give the player access to Birds, Insects, and Rodents; while Genetic Swap branches into an entirely unique set of transmissions. The Genetic Swap transmission allows the player to then choose from Mutative Regeneration (increasing chances of mutation) or Corpse Feeder (increasing infectivity where corpses are present). Both have two stages.

View Transmissions

The Neurax Worm gives the player two options to complete the game: the first, as usual, is to simply wipe out humanity. The second option is to enslave mankind. This plague is unique in that not all of its symptoms actually kill people directly but instead change the mental state of the host to one of aggression (murdering others) or depression (suicide).

View Symptoms

The Neurax Worm makes use of a unique ability named 'Trojan Planes'. These planes will randomly generate as bubbles throughout gameplay in infected countries - appearing in the same fashion as DNA, Infection, and Cure bubbles. The player can purchase three stages of Trojan Planes in the Abilities section with DNA points, each additional tier adding to the likelihood that a Trojan Plane bubble will appear. The bubble can then be tagged and dragged over to a designated target country, resulting in a plane flying there and starting an infection in said area. This ability is very useful for infecting hard to reach countries such as Greenland, Madagascar and Morocco. This ability can still be used even when the country has shut down its airport or if there is no airport present in the country to begin with, making the Neurax Worm a popular choice for players due to its unrivaled ability to reach any part of the world from anywhere.

After the Trojan Plane ability has been taken, the player will then be able to purchase the abilities 'Trojan Roamers' and 'Trojan Destroyers', each having two different effects in addition to increasing severity. Trojan Roamers increase infectivity rates in the country they land in, while Trojan Destroyers raise lethality by causing aggressive and destructive behavior in the host(s) arriving in the targeted area.

View Abilities

This plague type is relatively easy to master, and with the right strategy, it is the go-to plague type for most scenarios where the plague type is not locked.

DNA points pile up quickly with this disease type, and visibility is not an issue. Once the Trojan planes ability has been evolved, countries closing their borders, ports, and airports becomes a non-issue, which allows one to move about as they wish, all restrictions be damned.

This plague type also has the unique symptom Transcendence and its precursors, which have a cure effort-crippling effect plus the ability to bring about an early, successful end to a game, by enslaving humankind. Other fatal symptoms, such as Suicide, Brain Haemorrhage, and Acute Encephalitis, can cripple cure effort and kill large amounts of people in short amounts of time, unlocking the achievement Worm Food. There is an entire symptom tree dedicated to slowing the cure.

For this plague type, Transmission and Ability traits both increase severity, and thus the likelihood of the disease being detected, thus starting cure research, even before actual symptoms are present. Combined with the fact that the Neurax Worm is extremely easy to cure and doesn't have exceptional lethality, there can be trouble. However, several Symptoms that reduce severity can be purchased to hard-counter this and lowering the chances of a host noticing the worm.

This plague type requires quite a few DNA points to be spent in Symptoms before it can either kill or control the human population, so be sure to stock up once infection rates are steady. Another option is to use Sympto-Stasis to keep symptom costs stable, allowing for easier progress.


Please see Neurax Worm Strategy Guides.


  • The Neurax Worm is the only Special Plague that doesn't spawn a unique organisation dedicated to its destruction.
  • The pathogen is partially based off of Toxoplasma gondii while the disease it causes is inspired by an episode from the "Futurama" TV series. (Reference)
  • It lacks special genes and uses ones from the original game instead.
  • The Neurax Worm appears to be an unofficial mascot of Plague Inc. On Ndemic's Twitter , many pictures related to the game have a plush Neurax Worm in them.
    • There is also a special Neurax Worm that appears as an actual mascot for the game named "Neurie". It appears to be a Christmas tree ornament modelled after the icon for the Santa's Little Helper scenario.
    • Due to these reasons adding the fact Neurax Worm's old look is cuter than the Evolved version, the worm became the most popular plague type in the game, going as far as being the representing the game itself along with the Biohazard Logo.
  • The plague was once mistaken to be real with a video of a worm burrowing in a woman's brain, which causes a flu like symptom and numbness (Apraxia, similar to the fictional counterpart). A doctor has to be remove it surgically later.


Neurax Worm Theme


Neurax Worm enslaving Humanity victory message.

Stages of Infectivity (mobile)

Stages of Infectivity (Plague Inc: Evolved)

Special Plague Types

Neurax WormNecroa VirusSimian FluShadow Plague