Plague Inc. Wiki
Scenario mad cow disease.png "Panic over BSE almost shut down the beef industry in the 1990s. Imports were banned and burgers were off the menu until humanity got things under control. Recently though, unforeseen protein folding has resulted in a new variant of the prion - putting the whole food chain at risk. Is now the time to go vegetarian?"
— Plague Inc., Mad Cow Disease introduction paragraph

The Mad Cow Disease is a scenario in Plague Inc.

Scenario Attributes

Mad Cow Disease manifests as a Prion, with v2.CJD as its default name.

Confusion, Dysphagia, Headache, Memory Loss, Paranoia, Pins and Needles and Psychosis appear as pre-loaded traits.


Avocado Pathogen spreads through consumption of avocado. Increases infectivity, especially in rich countries
Beef Pathogen spreads through consumption of beef. Increases infectivity and chance of mutation. Popular in rich countries
Broccoli Pathogen spreads through consumption of broccoli. Slightly increases infectivity
Dairy Pathogen spreads through consumption of dairy products, such as milk and cheese. Increases infectivity and chance of mutation
Fish Pathogen spreads through consumption of ocean travelling and farm raised fish stocks. Increases infectivity and chance of mutation
Frozen Storage Resilience Cell-adapted shifts in protein structure lets pathogen thrive over long food supply chains. Increases ship and plane transmission
Hermetic Storage Resilience Minor protein alterations raise chance of pathogen remaining active via long haul food suply chains. Increases ship and plane transmission
Insect (Mad Cow Disease) Pathogen spreads through (accidental) consumption of insects. Increases infectivity and chance of mutation. Especially effective in arid climates
Lamb Pathogen spreads through consumption of lamb and mutton. Increases infectivity and chance of mutation
Maize Pathogen spreads through consumption of corn products. Increases infectivity, especially in poor countries
Mango Pathogen spreads through consumption of mangos. Increases infectivity, especially in hot climates
Pork Pathogen spreads through consumption of pork. Increases infectivity and chance of mutation
Potato Pathogen spreads through consumption of potatoes. Increases infectivity, especially in cold climates
Poultry Pathogen spreads through consumption of poultry. Increases infectivity and chance of mutation
Preservative Storage Resilience Significant amino acid variances trigger rapid pathogen development when refrigerated. Increases ship and plane transmission
Rabbit Pathogen spreads through consumption of rabbit. Increases infectivity and chance of mutation. Especially effective in rural countries
Rice Pathogen spreads through consumption of rice. Greatly increases infectivity, especially in hot climates
Wheat Pathogen spreads through consumption of wheat. Increases infectivity
Wild Game Pathogen spreads through consumption of wild game. Increases infectivity across land borders and raises mutation chance


Confusion Dopamine production stimulated to cause bouts of confusion in host. Harder to concentrate on complex work.
Dysphagia Difficulty swallowing causes occasional coughing when eating. Slight increase in infectivity.
Headache Strong headache behind the eyes causes discomfort and reduces ability to work.
Memory Loss Recent memories become nebulous in patients, replaced with vague historical recollections. Negatively impacts cure process.
Paranoia Irrational delusions and mental symptoms. Victims distrust of others makes them unlikely to seek treatment or cooperate with others.
Pins and Needles Breakdown of the nervous system causes victims to experience numbing or tingling sensations in extremities.
Psychosis Psychotic episodes lead to occasional bursts of extreme violence which can be lethal. Increases infectivity and slows future research speed.
Acute Encephalitis Multiple inflammatory lesions in the brain triggered. Causes neurological damage resulting in death.

Cross-Infection Traits

These are unlocked after Human Cross-infection has been obtained.

Abscesses Pockets of infected flesh are painful and act as breeding grounds for the pathogen, increasing infection rates when burst.
Ataxia Cerebellum becomes vulnerable to infection, impairing victims' coordination, balance, and speech.
Blindness Primary visual cortex disconnected causing blindness. Significantly reduced awareness and causes fatal accidents.
Cannibalism Extreme Compulsion to bite or eat other humans - significantly increasing infectivity as well as lethality.
Coma Neuropathic effects in the brain stem cause loss of consciousness and sometimes death. Significantly harder to cure.
Coughing Chance of infection by spreading pathogen into surroundings. Especially in high density, urban areas.
Delirium Reduction in cognitive function causes irrationality and paranoia. Can be fatal and significantly slows future research speed.
Hallucinations Occipital lesions created, causing severe hallucinations. Lack of awareness increases transmission chance as well as risk of injury.
Inflammation Inflammation obstructs bodily processes. Swelling can obstruct breathing and be fatal.
Insanity Neuropathic action of the pathogen in the frontal lobe causes severe emotional and behavioural abnormalities. Significantly harder to cure.
Mania Excess serotonin production triggered. Manic episodes lead to increased contact with others and inability to focus.
Necrosis Large swathes of infected tissue lose blood supply and become fatal sources of gangrene. Decomposed bodies remain a vector of transmission.
Paralysis Pathogen destroys motor neurons to cause paralysis. Significantly harder to cure and lethal.
Pneumonia Serious fluid build and discharge from the lungs. People in cold climates especially vulnerable.
Pulmonary Oedema Potentially fatal heart abnormality causes breakdown of respiratory system, releasing pathogens into the air.
Seizures Random blackouts and fits reduce the patient's ability to function independently. Can be fatal
Systemic Infection Pathogen affects multiple organ and tissue types, causing body-wide infections that spread fast and can be fatal.
Total Organ Failure Catastrophic cell death of multiple tissue types causes body-wide organ failure and rapid death.


Mad Cow Disease has two unique abilities, but shares the vast majority of them with standard plagues otherwise, and additionally lacks Drug Resistance 1 as well as Drug Resistance 2.

Plant Dissemination - Adjustments to protein folding give Prion the ability to infect plant life. Unlocks new transmissions.

Human Cross-infection - Radical folds of amino acid sequence allow prion to be transferred between humans. Unlocks new symptoms.



  • Mad Cow Disease is a reference to the nickname of Bovine spongiform encephalopathy (BSE), a lethal, neurodegenerative disease caused by misfolded prion of unknown origins affecting first spotted in British cows since the late 1980s, which in turn was responsible for the Variant Creutzfeldt–Jakob Disease (vCJD) outbreak in the 1990s due to humans ingesting contaminated Cow tissue as well. This was then followed by multiple expansive bans against British beef.
    • However, the in-game Mad Cow Disease, as with regular Prions, are incredibly easy to cure and develop symptoms rapidly and have multiple transmissive options, unlike their real-life counterparts where infected populations can remain asymptomatic for decades with limited transmissions easily preventing potential outbreaks - Only a mere 177 people were killed due to humanity slaughtering around 4,000,000 cattle in the wake of this disaster.
  • Mad Cow Disease was introduced in the Mutation 1.15 update with Flight Club and Where Is Everyone?.
    • The update also emphasized this scenario as a "Mega Moo-Tation".
  • Plant life must be infected in order to kill vegans in the game, since vegans do not consume dairy, unlike vegetarians. However, this does not apply if you managed to infect the world before the world knew that your disease is there, since everyone will eat normally and therefore can be infected.
Scenarios in Plague Inc.
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World Changes
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