 Knowledge of a pathogen's host specificity allows professionals in the research and medical industries to model pathogenesis and develop vaccines, medication, and preventive measures to fight against infection.Methods such as cell engineering, direct engineering and assisted evolution of host-adapted pathogens, and genome-wide genetic screens are currently being used by researchers to better understand the host range of a variety of different pathogenic organisms.A pathogen displays tropism for a specific host if it can interact with the host cells in a way that supports pathogenic growth and infection.