Rat Plague

"A crawling foulness will overcome you because you did not shut the gates of your heart to iniquity."

- A prophetic warning of the rat plague

The rat plague (called "The Doom of Pandyssia" by the Heart ) is a rodent-borne contagious disease, responsible for the decimation of the population of Dunwall during the events of Dishonored. According to studies conducted by Doctor Galvani, the plague has an unusual migration pattern: the oldest strains of the disease exist in the city's slums and other impoverished districts, rather than the docks, the most likely location for invasive foreign pests to have entered the city.

Corvo Attano eventually discovers that the plague was introduced to Dunwall by Royal Spymaster Hiram Burrows as a means of putting an end to poverty in the city, with the results proving catastrophic.

Origins and Spread
The rat plague originated near an unnamed river in south-central Pandyssia. The plague is carried by Pandyssian Bull Rats, which are immune to the disease but transmit it among themselves, possibly through mites. A single rat bite can infect a human, and humans can spread it to each other.

In 1835, during The Month of Clans, Royal Spymaster Hiram Burrows deliberately introduced the Pandyssian Bull Rat into Dunwall's impoverished districts. His goal was to infect and kill the city's poorest inhabitants. However, the disease quickly spread beyond those districts to the rest of the city and beyond.

Symptoms and Treatment
"Hear her terrible moans! The disease is both painful and disfiguring."

- The Heart

Symptoms of the plague include discolored skin (particularly on the face and chest), weight loss, and thinning of the hair. As the disease progresses, the lungs and brain become more damaged, leaving its sufferers with a chronic cough and a significant decrease in cognitive ability.

Late-stage symptoms include subconjunctival hemorrhaging, which causes blood to drip from the eyes, and infestation by parasitic stinging insects. Early efforts to combat the plague are fruitless once these symptoms surface, and prior to the discovery of a cure, the disease is lethal at this stage. Plague sufferers in the last stages of the disease are known colloquially as "weepers".

Preventative methods, such as Sokolov's Elixir and Piero's Spiritual Remedy, exist but are expensive and scarce. As such, they are generally not affordable to the majority of citizens in Dunwall. Cheaper and less effective methods for combating the disease have emerged, including bootleg elixir produced by the Bottle Street Gang, homeopathic remedies, and ritualistic ceremonies. Although official sources discourage the use of these methods, given the inaccessibility of elixirs, they are still commonly used.

Natural resistance to the plague does exist, as explained by a doctor in the Flooded District who is caring for a dying patient. He emphasizes, however, that the chances of the body fighting off the disease on its own are "a thousand, probably ten thousand, to one." There are also those who carry the plague but will not themselves turn into a weeper.

Prevention Efforts
"There is always a cure! The question is - what are you willing to sacrifice to have it?"

- Anton Sokolov

The rat plague has killed half of Dunwall's population since its initial spread. Empress Jessamine Kaldwin sent Corvo to solicit the other nations of the Empire for aid in stemming the plague, but the effort was in vain, and Dunwall was subsequently blockaded.

While the Empress was unwilling to use draconian measures of containment to prevent the plague's spread, others in her government were not; following her assassination, Lord Regent Burrows instituted martial law and commissioned Anton Sokolov to invent new methods of containment. Walls of light quarantine infected areas, a dusk-to-dawn curfew has been instituted (both to reduce human contact with rats and to decrease the chance of infected individuals breaking quarantine), and both civil and religious officials were given wide-reaching power to deal with disruptive or uncooperative persons. Even though these measures were considered harsh or even tyrannical by many, they did help to stop the movement of infected people and slow the spread.

Red crosses marked buildings where the plague has struck, and linen-wrapped bodies awaiting disposal littered Dunwall's streets and residences. Guards were instructed to place these corpses on barges and then trains bound for the Flooded District by official Dead Counters; however, some guards took to dumping them into the city's waterways to avoid prolonged exposure to the disease, if the bodies were not first consumed by rats.

Individuals suspected of contracting the plague had their property and assets immediately seized by the City Barrister, which were transferred to the state if there were no surviving kin to inherit. Corruption and bribery within the Legal District led to false claims of infection on otherwise healthy persons so that their property could be seized for political and financial gain.

During the infestation, scientists such as Doctor Galvani and Anton Sokolov conducted research to find a cure for the plague, occasionally in secret due to a ban on certain scientific practices. In the low chaos ending of Dishonored, provided that both Piero Joplin and Anton Sokolov survive, they combine their efforts and find a cure for the plague that heals even late-stage victims by 1838. They can at one point be seen curing weepers in their shared laboratory.

Trivia

 * The rat plague is loosely based on the real-world bubonic/septicemic plague. It too was an all-consuming disease that was thought to be carried by rodents in the Middle Ages (in reality, it was carried by the fleas living in the rats' fur, as well as through direct contact with those already infected, but this was not discovered until centuries later). The environment of Dunwall also reflects this parallel, as bodies littered the streets during the bubonic plague, with the same happening in Dunwall. Also, houses infected by the bubonic plague were marked with a cross, which corresponds with those marked on select houses in Dunwall.
 * An old Serkonan poem tells the tale of death caused by a "a disease from the East", suggesting that there was an awareness of the plague long before it reached Dunwall.
 * A guest at the Boyle Party claims that the "rats came a half year before the Empress died".
 * When examining the courtesans in the Golden Cat, the Heart will comment: "The streetwalkers. Only the rats spread the plague faster." hinting that disease also spreads through sexual contact.
 * The plague caused a number of riots, often shutting down streets.
 * A number of individuals believed that the plague was spread by infectious winds, and all one had to do was hide from those until they moved on.