Alternative form of 病原

a sick friend, a friend who is ill / different people who have the same disease (not necessarily friends)

seedbed / plant nursery

nanosecond - a measure of time equal to one billionth of a second. Abbreviation: ns

childhood diseases

a millisecond

microsecond - a unit of time equal to 0.000001 seconds (i.e., one-millionth of a second) and commonly represented with symbol µs.

Kyūjitai form of 描写 (“description; depiction; portrayal”)

even, equal

cause or source of a disease, pathogenesis, etiology