What is the main difference between an infectious and noninfectious disease?

One can be spread, transmitted, usually through the air.

infectious disease- Can be spread

noninfectious disease- Cannot be spread

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Explanation: An infectious disease can be transmitted from one person to another, while a non-infectious disease cannot be spread through person-to-person contact.  

Infectious diseases are caused by pathogenic micro-organisms such as bacteria, viruses, fungi or parasites. These micro-organisms are contagious, meaning they can be transmitted from one person to another.

Non-infectious diseases are not caused by pathogens and therefore cannot be spread from one person to another. Instead, non-infectious diseases are caused by factors such as genetics, malnutrition, environment and lifestyle.

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