Final answer:
A public health nursing specialist needs a graduate level education with a focus in public health science, potentially including an MPH, MD, or PhD.
Step-by-step explanation:
A specialist in public health nursing typically requires a graduate level education with a focus in public health science. Epidemiologists, for example, have a bachelor's degree in a related field and most go on to obtain a master's degree in public health (MPH). Many also hold a medical degree (MD or DO) or a PhD in an associated field such as biology or microbiology.
The focus of public health is to prevent and manage diseases, and professionals in this field require significant education and training for this complex and critical work.