those infected with any kind of flower sneeze flowers    the flowers grow on the lining of their lungs.

those infected with a virus/ fungi have [insert infection] coming from their bones. so ribs may be partially exposed, arm/ leg bones may be shown with things gowing from them. this can also happen with the skull

being infected with vegetation will have whatever vegestable they are infected with growing from their backs, arms, and/ or head

the species will have insect traits with a mostly mammalian-alien body.