What type of measure aims to improve health or alter the course of disease?

The correct choice, intervention, refers to a specific strategy or action taken to improve health outcomes or modify the progression of a disease. Interventions can include a wide array of activities such as medical treatments, lifestyle changes, behavioral modifications, or educational programs aimed at preventing illness or managing existing health conditions. The focus of an intervention is on actively making changes to influence health positively.

In contrast, the other terms do not pertain specifically to measures aimed at improving health. Macrophages are immune cells that play a role in the body's defense against pathogens but do not represent a health measure or strategy. Memory cells are involved in the immune response, helping the body remember past infections but are not themselves a systematic method to alter health. A pedigree is a diagram that shows the lineage or genealogy of individuals but does not directly relate to health measures or interventions. Thus, intervention stands out as the correct answer in this context.