Fixes

code/datums/diseases/_disease.dm

@@ -119,7 +119,7 @@ GLOBAL_LIST_INIT(diseases, subtypesof(/datum/disease))
 
 	var/turf/target = affected_mob.loc
 	if(istype(target))
-		for(var/mob/living/carbon/C in oview(spread_range, affected_mob))
+		for(var/mob/living/carbon/human/C in oview(spread_range, affected_mob))
 			var/turf/current = get_turf(C)
 			if(current)
 				while(TRUE)
@@ -128,6 +128,8 @@ GLOBAL_LIST_INIT(diseases, subtypesof(/datum/disease))
 						break
 					var/direction = get_dir(current, target)
 					var/turf/next = get_step(current, direction)
+					if(!current.CanZASPass() || !next.CanZASPass(get_turf(turn(direction, 100))))
+						break
 					current = next
 
 /datum/disease/proc/cure()
@@ -153,8 +155,13 @@ GLOBAL_LIST_INIT(diseases, subtypesof(/datum/disease))
 
 /datum/disease/proc/IsSpreadByTouch()
 	if(spread_flags & CONTACT_FEET || spread_flags & CONTACT_HANDS || spread_flags & CONTACT_GENERAL)
-		return 1
-	return 0
+		return TRUE
+	return FALSE
+
+/datum/disease/proc/IsSpreadByAir()
+	if(spread_flags & AIRBORNE)
+		return TRUE
+	return FALSE
 
 /datum/disease/proc/remove_virus()
 	affected_mob.viruses -= src

code/datums/diseases/appendicitis.dm

@@ -9,7 +9,7 @@
 	viable_mobtypes = list(/mob/living/carbon/human)
 	desc = "If left untreated the subject will become very weak, and may vomit often."
 	severity = MINOR
-	disease_flags = CAN_CARRY|CAN_CARRY
+	disease_flags = CAN_CARRY|CAN_RESIST
 	visibility_flags = HIDDEN_PANDEMIC
 	required_organs = list(/obj/item/organ/internal/appendix)
 	bypasses_immunity = TRUE