Infection is the first step on the road to Disease. Infections haven't turned yet to Disease and often don't cause any symptoms.
Disease suggest that a person has a medical problem with obvious signs and symptoms.
Example:
STI and STD are different, so dont interchangeably use it.
An STI is only considered a disease when it causes symptoms.
Conclusion:
Infection and Disease is interconnected but differnet frim each other. Also with proper handling of infection will prevent the escalation of disease.
Knowledge is power.