How is a systemic infection defined?

A systemic infection is defined as one that spreads within the body, affecting multiple organ systems or the entire organism. This type of infection can originate from a localized area and move into the bloodstream, resulting in a wide-reaching impact across various bodily systems. Examples of systemic infections include sepsis and certain viral infections that can affect organ function throughout the body.

In contrast, infections that spread locally remain confined to a specific area and do not involve wider systemic effects. Those that remain in one area do not enter the bloodstream or affect other systems. Furthermore, while some infections can indeed be purely viral, systemic infections can also be caused by bacteria, fungi, or other pathogens. The defining characteristic of a systemic infection is its capacity to spread and impact the body as a whole, rather than being limited to a single location or type of pathogen.