New Health/Disease and Plague Mechanic

[Alexander's Hetaroi]

In this newest expansion we know that we are getting a scenario focused around the Black Plague and they are introducing a new health mechanic in that scenario.
They also said they didn't want to implement this into the regular game yet, which sounds like they will in the future.
Here's what I would want not knowing anything about the scenario, and would like to know other people's opinions and how they would implement a new health system in the regular game. Keep in mind I'm not a healthcare or medicine professional at all. I'm just a history nerd that knows the impact of diseases and plagues in history and would like for it to be implemented in the game.

Diseases: Diseases can randomly pop up at anywhere on the map. The most popular places, especially at the beginning of the game, would be in extreme locations such as settling in snow/tundra or rainforest. If a city population also goes too long without adequate food they may susceptible to diseases as well as inadequate drinking water such as coastal water or no river.
Depending on factors such as the new climate change and growing population diseases may happen more and become more intense turning into plagues.

Plagues: If diseases are prolonged and start to spread to different cities they can be considered a plague. Plagues will be able to be named and will receive random promotions. Plagues will become stronger and expand quicker if not stopped.

Health: In order to stop the spread of diseases and plagues there is a new district and buildings along with revamped old ones. Early buildings will help but to fully keep your citizens healthy you will need the late buildings.

New District: Medical Center
First Tier: Apocathery (unlock in Medieval Era at new tech?) Prevents the spread of diseases and plagues in city where it was built. More effective for every farm, pasture, and plantation in the city.
Second Tier: Hospital (unlock at Sanitation) Prevents the spread of diseases and plagues in the city where it was built and other cities at least four tiles away. Yields faith if there is a Holy Site District present with a worship building. Used to build medics maybe.
Third Tier: Public Health Clinic (unlocks in Atomic Era at new Tech?) Prevents the spread of diseases and plagues in city where it was built and other cities at lest six tiles away. Requires a lot of gold maintenance.

Existing Buildings and Districts:
Aqueduct: Prevents the spread of diseases in a city if there was no source of fresh water.
Sewers: Prevents the spread of diseases especially in large cities with a population of at least 10.
Research Lab: If you have a Medical center in the city this helps prevent the spread of diseases even more.

New World Congress Emergency: Pandemic Treatment
Special Session when a plague has crossed over to at least two civilizations.
Maintain your own medical buildings.
Send gold and research agreement to affected Civs for specific techs needed or give them the eureka if you already know the tech.

 

[Gedemon]

Here is how I plan to handle Health and Diseases, but not for the regular game, my mod use real population values and resource stockpile with supply lines, yet it's still generic enough to be adapted I think:

• Each City has a base "Health" value relative to it's population size that is:
  • Raised by :
    • Health-related buildings (Herborist, Hospital, Sewer, ...)
    • Forests
    • Food Variety
  • Lowered by:
    • Surpopulation
    • Jungle, Marsh
    • Pollution (production from Buildings)
    • Food rationing, Famine
    • No fresh water supply

• Each Turn:
  • Health = BaseHealth + (RaiseValue -LowerValue) with -100 < Health < 100
  • x% "generic" disease in population, based on Health value
  • "Medicine" resource (produced from Plants) consumption growth with % disease
  • shortage of Medicine raise Mortality rate

• Epidemic Diseases
  • There is a defined set of possible Epidemic Diseases with specific properties like:
    • Frequency
    • Mortality
    • Contagion
    • Max Acquired Immunity
  • Each Epidemic as it's own "Spawning Probability" value in each City
  • Spawning Probability start at a negative value (for ex -100) and change each turn, pondered by Health value (+/-) and some (optional or required) conditions that may be specific to a Disease type like for example:
    • No fresh water (Cholera)
    • Overpopulation (Typhus)
    • Specific Features (Jungle, Marsh for Malaria)
  • An Epidemic can not spawn before its Spawning Probability > 0
  • When an Epidemic starts, its Spawning Probability is restored to -100 and won't change until the Epidemic has ended in the city
  • The Epidemic may spread to other linked Cities by raising their own Spawning Probability for that Disease, if it has a Contagion value (Influenza, Plague, ...)
  • Units can also be affected, either by being linked to (or attacking) cities/units with a contagious disease, or by being on terrain/features related to diseases)
  • Units carrying a contagious Diseases can affect enemy cities when attacking (and friendly units/cities by proximity/link)
  • When started, an Epidemic in a city has a "strength" value that is lowered each turn based on the city Health value and available Medicine resource
  • Each turn, a percentage of population is killed based on the Disease mortality value until its strength reach 0.

 

[Alexander's Hetaroi]

I've decided to revive this thread instead of talking about it in the Winter Update thread.
Here are some changes/updates that I would make:

Apothecary and Medical Facility district unlocks at Mathematics.
Hospital unlocked at Sanitation
Health Clinic unlocked at Chemistry.

New Medical Support Units: Are able to cure citizens inside cities when epidemics break out.
Plague Doctor: Similar to role in Scenario and will need Apothecary building to recruit when an epidemic is started. Upgrade to Medic at Sanitation
Medic: Same role in regular game plus the ability to cure more citizens. Buildable with Hospital building. Upgrades to Supply Convoy at Combustion
Supply Convoy: Same role plus the ability to cure more citizens than the medic.

Diseases will originate more frequently based off of the terrain where you settle next to. The rising sea levels will dramatically increase diseases later on.
More frequent places: Rainforest, marsh, Oasis, Coastal
Neutral: Grasslands, Plains, Rivers, Lake
Less Common: Desert, Snow, Tundra
Cities under siege are also more susceptible.

If you build an aqueduct you negate the option of diseases appearing from the Coast, River, and Lake.
Sewers will be needed for cities with larger populations.

When a disease comes prevalent in a Civ they will have a chance to name it (random name generator) if it is an AI civ. it will also get a random promotion.
Waterborne: Travel faster along rivers and to cities with harbors.
Dust borne: Travels faster through a Haboob
Viral: Cities with more populations are affected.
Non-contagion: Spreads slower
If anybody can think of more it would be greatly appreciated.

Pandemic Emergency:
When a disease hits at least two civs one of those Civs can call a Pandemic Emergency
Other Civs that join will gain points by:
Maintaining Medical Facility and Research lab buildings.
Sending medical support units to affected areas.
Run Find Cure project in cities with a Medical Facility

 

[Boris Gudenuf]

Diseases will originate more frequently based off of the terrain where you settle next to. The rising sea levels will dramatically increase diseases later on.
More frequent places: Rainforest, marsh, Oasis, Coastal
Neutral: Grasslands, Plains, Rivers, Lake
Less Common: Desert, Snow, Tundra
Cities under siege are also more susceptible.

The water source for a city makes a big difference. If a city is on or within one tile of a river, that's assumed to be the source of potable water. That means any other City Center or District Upstream (away from the coast), increases the general chance of an outbreak, and especially the chance of a Water-borne outbreak. Aqueducts that take water from the river gives the same outbreak chance, but aqueducts taking water from a mountain ('mountain spring'?) are much safer.
In order from Worst to Best water sources: Marsh, Oasis, Lake, River 0 with 'River' being variable depending what else is happening to the water in it. Also, having a Rainforest or Marsh tile next to a city should drastically increase your risk because you would, presumably, be within range of all the insect disease vectors from those two types of Disease Sources.

When a disease comes prevalent in a Civ they will have a chance to name it (random name generator) if it is an AI civ. it will also get a random promotion.
Waterborne: Travel faster along rivers and to cities with harbors.
Dust borne: Travels faster through a Haboob
Viral: Cities with more populations are affected.
Non-contagion: Spreads slower
If anybody can think of more it would be greatly appreciated.

As noted above, waterborne may travel faster down a river, but the big increase in chance of outbreak there is pollution of the water within the city: no sewer, no aqueduct to a 'clean' source.
Dust Borne isn't quite correct: germs don't travel well in dust storms at all. Airborne, from the 'common cold' virus to the pneumonic plague, on the other hand, spread very rapidly, based on the crowding - more population in a city, faster it spreads.
Viral isn't really a type of spread: viruses can be spread by water, contact, or airborne.

Many human epidemics spread from animals - notoriously, from livestock like cattle and sheep, poultry and pigs, all of which are vectors for disease that spread to people. So, perhaps the more sheep, cattle or horse Resources in the city radius could increase chances of an outbreak?
Number of Trade Routes, especially from cities/populations having a higher chance of outbreak, dramatically increases risk of outbreak. This could be countered by Quarantine, a Medieval Civic that cuts your Trade Income in half (because you are delaying receipt of goods for X weeks before letting them into the city) but reduces the outbreak risk from Trade Routes to 0.

 

[Alexander's Hetaroi]

As noted above, waterborne may travel faster down a river, but the big increase in chance of outbreak there is pollution of the water within the city: no sewer, no aqueduct to a 'clean' source.
Dust Borne isn't quite correct: germs don't travel well in dust storms at all. Airborne, from the 'common cold' virus to the pneumonic plague, on the other hand, spread very rapidly, based on the crowding - more population in a city, faster it spreads.
Viral isn't really a type of spread: viruses can be spread by water, contact, or airborne.

Thanks for the input.
I'm trying to think of gameplay mechanisms, and names, for random disease promotions and that's all that I could come up with, even if they might not make as much sense realistically.