Final answer:
When a disease is dying out, it means that the number of cases or the spread of the disease is decreasing over time. The source may not have been eliminated and it could be spreading from person to person. This can happen with diseases like tuberculosis in specific regions.
Step-by-step explanation:
In the context of diseases, when it is stated that a disease is dying out, it means that the number of cases or the spread of the disease is decreasing over time. It suggests that the disease may be spreading from person to person, but the source of the disease has not been eliminated. The source of the disease may also be intermittent, meaning it occurs sporadically. For example, diseases like tuberculosis can be under control in some regions but may come back in urban areas with a high concentration of immunocompromised people.