What is a patient considered who is infected with a virus but who does not have any outward sign of the disease?

A) Pathogen
B) Fomite
C) Vector
D) Carrier

A patient who is infected with a virus but has no outward signs of the disease is called a carrier. They may be asymptomatic or in the incubation period of the disease. Carriers can still spread the virus to others, making them a potential source of infection.