can_contract_disease_trait_scope_trigger

can_contract_disease_trait_scope_trigger = {
	save_temporary_scope_as = sick_character_check

	# Is not immune to disease
	NOT = { has_character_flag = immune_to_disease }

	#Doesn't already have the trait
	NOT = { has_trait = $DISEASE$ }

	#Only get measles once
	trigger_if = {
		limit = { $DISEASE$ = trait:measles }
		NOT = { has_character_flag = disease_immunity_measles }
	}

	#Only get bubonic plague once
	trigger_if = {
		limit = { $DISEASE$ = trait:bubonic_plague }
		NOT = { has_character_flag = disease_immunity_bubonic_plague }
	}

	#Young characters do not get gout
	trigger_if = {
		limit = { $DISEASE$ = trait:gout_ridden }
		current_weight >= 50
		is_young_character = no
	}

	trigger_if = { #Lover's pox can only be contracted if you are sexually active
		limit = {
			$DISEASE$ = trait:lovers_pox
			is_imprisoned = yes
		}
		imprisoner = {
			OR = {
				AND = {
					scope:sick_character_check = { is_in_prison_type = dungeon }
					any_prisoner = {
						OR = {
							has_relation_lover = scope:sick_character_check
							any_consort = {
								this = scope:sick_character_check
							}
						}
					}
				}
				AND = {
					scope:sick_character_check = { is_in_prison_type = house_arrest }
					OR = {
						any_prisoner = {
							OR = {
								has_relation_lover = scope:sick_character_check
								any_consort = {
									this = scope:sick_character_check
								}
							}
						}
						any_courtier = {
							OR = {
								has_relation_lover = scope:sick_character_check
								any_consort = {
									this = scope:sick_character_check
								}
							}
						}
					}
				}
			}
		}
	}

	# Check to see that there is someone for you to have sex with if you are traveling
	trigger_if = {
		limit = {
			$DISEASE$ = trait:lovers_pox
			is_travelling = yes
			# Do not block Goliardic Shenanigans!
			involved_activity ?= {
				NOT = { has_activity_type = activity_adult_education }
			}
		}
		current_travel_plan = {
			any_entourage_character = {
				OR = {
					has_relation_lover = scope:sick_character_check
					any_consort = {
						this = scope:sick_character_check
					}
				}
			}
		}
	}

	#Secondary requirements (mutually exclusive diseases or immunity)
	OR = {
		NOR = { #No secondary requirement
			$DISEASE$ = trait:ill
			$DISEASE$ = trait:smallpox
			$DISEASE$ = trait:measles
			$DISEASE$ = trait:bubonic_plague
		}
		AND = {
			$DISEASE$ = trait:ill
			NOT = { has_trait = pneumonic }
		}
		AND = {
			$DISEASE$ = trait:smallpox
			NOT = { has_character_flag = disease_immunity_smallpox }
		}
		AND = {
			$DISEASE$ = trait:measles
			NOT = { has_character_flag = disease_immunity_measles }
		}
		AND = {
			$DISEASE$ = trait:bubonic_plague
			NOT = { has_character_flag = disease_immunity_bubonic_plague }
		}
	}

	#No disease stacking

As written in game/common/scripted_triggers/20_health_triggers.txt.