What strategies have the potential to prevent the spread of disease?

Immunisation, public health promotion to raise awareness and knowledge (e.g. Ads, at the provider-patient level)
Targeting and improving infrastructure for public welfare! e.g. Sewerage services for clean water

Screening for early diagnosis and treatment
Quarantining if required..

Though the word "potential" is throwing me off a bit here, are they asking you for novel strategies instead of solid ones?

This is first hand knowledge, top-level athletes, successful business people and achievers in all fields all  set goals. setting  goals  gives you long-term vision and short-term motivation . it focuses your acquisition of knowledge, and you to organize your time and your resources so that you can make the very most of your life.