create_contagion_list_effect

create_contagion_list_effect = {
	$CONTAGION_COURT_OWNER$ = {
		if = {
			limit = {
				NOR = {
					this = $SICK_CHARACTER$
					is_in_list = contagion_list
				}
			}
			add_to_temporary_list = contagion_list
		}
		every_courtier_or_guest = {
			limit = {
				NOR = {
					this = $SICK_CHARACTER$
					is_in_list = contagion_list
				}
			}
			add_to_temporary_list = contagion_list
		}
		every_prisoner = {
			limit = {
				NOR = {
					this = $SICK_CHARACTER$
					is_in_list = contagion_list
				}
			}
			add_to_temporary_list = contagion_list
		}
	}
	$SICK_CHARACTER$ = {
		every_scheme = {
			limit = {
				friendly_scheme_trigger = yes
				NOT = { scheme_target_character = { is_in_list = contagion_list } }
			}
			scheme_target_character = { add_to_temporary_list = contagion_list }
		}
		every_targeting_scheme = {
			limit = {
				friendly_scheme_trigger = yes
				NOT = { scheme_owner = { is_in_list = contagion_list } }
			}
			scheme_owner = { add_to_temporary_list = contagion_list }
		}
	}
}

As written in game/common/scripted_effects/20_health_effects.txt.