Continuity mistake: After Kat finds a bedroom for herself, the long sheer white curtain hanging near the framed photo of Amelia repeatedly changes between pulled open or closed; particularly noticeable when Kat dumps her clothes from the black trash bag and tosses a ball of socks into Casper's mouth. (00:25:15)
Continuity mistake: Carrigan decides to make Dibs a ghost, so she goes after him with a double-headed axe. Then, when Carrigan slips on the muddy goo, her black pointy toe high heels turn into beige flat rubber-soled shoes, seen in her close-up as her foot lifts up. (01:11:45)
Chosen answer: It was most likely Pneumonia, which was very deadly before the discovery of antibiotics.
Donald Jenkins