Which of the following describes a host in a disease context?

In the context of disease, a host is defined as an organism that harbors a pathogen, which can lead to infection and illness. Option B accurately captures this definition by referring to "one that is getting sick." This implies that the individual is at least showing signs of infection or being affected by a disease, aligning well with the accepted use of the term "host" in medical and scientific descriptions.

To clarify the other options, the idea that a person who spreads disease without symptoms refers to a carrier rather than a host, as they may not exhibit overt signs of being affected. Describing a healthy individual does not fit the notion of a host in the disease context because a host typically experiences some level of involvement with the disease, even if asymptomatic. Lastly, a vector for infection refers to organisms that transmit pathogens from one host to another rather than being a host themselves. Therefore, option B is the most appropriate descriptor for a host in the context of disease.