What term describes an aggregation of cases of a disease within a specific time period?

The term that accurately describes an aggregation of cases of a disease within a specific time period is "cluster." A cluster refers to a concentration of cases that occur in a defined geographical area and timeframe, which indicates an increase in cases relative to the expected number. This term is often used in epidemiology to investigate patterns of disease occurrence and to track potential outbreaks.

In contrast, an outbreak typically refers to a sudden increase in the number of cases of a disease in a specific location, whereas an epidemic signifies a wider occurrence of a disease that exceeds normal expectations across larger populations or regions. Prevalence, on the other hand, indicates the total number of cases of a disease in a population at a specific time, rather than focusing on the aggregation of new cases over a specific period. Thus, "cluster" is the most accurate term for describing the scenario presented in the question.