What 4 elements are required for the spread of infection to occur?

The four elements required for the spread of infection are a pathogen (the infectious agent), a reservoir (the natural habitat where the pathogen lives), a mode of transmission (the way the pathogen is spread, such as direct contact or airborne), and a susceptible host (an individual who can become infected). These elements interact in a cycle, facilitating the transmission of infections. Breaking any link in this chain can help prevent the spread of disease.