What is defined as a disease whose incidence has recently increased and poses a significant health risk?

The term that best fits the definition of a disease whose incidence has recently increased and poses a significant health risk is "emerging disease." Emerging diseases are typically new infections that have recently been identified or are increasing in incidence or geographical range. Factors such as environmental changes, globalization, and increased human-animal interactions can contribute to the emergence of these diseases, which can pose serious public health threats.

Chronic diseases, on the other hand, are long-lasting conditions that usually cannot be prevented through vaccines or cured with medication. Endemic diseases are those consistently present in a specific geographic area or population, and they do not necessarily exhibit recent increases in incidence. Infectious diseases refer broadly to diseases caused by pathogens, which can include both emerging diseases and those that are endemic or have a stable incidence rate. However, the key aspect of the question highlights the recent increase in incidence, making "emerging disease" the most accurate choice.