Which term refers to the spread of pathogens between different species or objects?

The term "cross infection" refers specifically to the transmission of pathogens that can occur when infectious agents are spread between different species or objects. It often involves the transfer of bacteria, viruses, or other microorganisms from one host to another, particularly in cases where an infection moves from one species to another, such as from animals to humans, or from surfaces to people.

In the context of infection control and public health, understanding cross infection is crucial because it highlights the importance of hygiene practices and measures to prevent the spread of infections across different hosts or environments. This is particularly relevant in healthcare settings where pathogens can move between patients and medical staff or contaminated surfaces.

The other terms do carry relevance but are broader or more general in their application. For example, "transmission" is a general term for how pathogens move from one host to another, but it does not specifically imply that different species or objects are involved. "Infection" refers to the invasion of the body by pathogens and their multiplication, while "contagion" typically describes how an infectious disease can spread from one person to another, rather than specifying cross-species transmission. Thus, cross infection provides a more precise understanding of the dynamics behind how infections can spread between different species or settings.