Each pawn has there own mechanism for contraction that will be checked periodically based on the frequency set in the options. They therefore do not follow the vanilla process of a random chance of an illness per time period to a listing of pawns.

There is then a base random chance for contraction. More serious illnesses and ailments will add to the chance of contraction (which have weighted characteristics), this then indicating the overall general health of the pawn. This will further be "offset" by individual and environmental factors, as well as activity.

Individual factors:

Aged less than 40 reduces the chance, whereas aged older increases the chance.

If they have the trait "frail" this will increase the chance.

If their body type is fat it will increase the chance.

If the pawn is starving this will increase the chance though if well fed this will allow for the possibility of indigestion.

Immunity traits will vary the offset both in a positive and negative way.


Environmental factors:

If the outdoor temperature is less than 21C it will increase the chance and scales with various temperature points. If the outdoor temperature is greater than 29C is will decrease the chance (again scaled).

Relative cleanliness of the pawns environment will vary the chance of contraction in both a positive and negative way. With some ailments more associated with poor general hygiene. (there is additional synergy here with Dubs bad hygiene mod where used).


Activity factors:

If the pawn is well rested there is a possibility of restlessness, whereas poor rest can incur an increase in the chance to contract an ailment.

If the pawn is associated with physical activities then the possibility of knicks and sprains is apparent. Similarly if the pawn is associated with plant activity they could then contract hay fever.


There are other more subtle nuances and rules but the above should provide an overall indication how the potential for contraction is effected by other elements.