infected person; carrier
Refers to a person who has contracted an infectious disease and can potentially transmit it. Commonly used in medical and public health contexts.
新型コロナウイルスの感染者が急増している。
The number of people infected with the novel coronavirus is surging.
He was an asymptomatic carrier.
保菌者 is a more technical term for a carrier of bacteria, often without symptoms, whereas 感染者 is broader and commonly used for viral infections.
uninfected person
chronic carrier; persistent carrier of infection
newly infected person; new case
Compound of 感染 (kansen, 'infection') + 者 (sha, 'person').