Tissue tropism refers to the cells and tissue of a host organism that make the host hospitable to the growth of certain types of viruses and bacteria. While some bacteria and viruses can infect many types of cells and tissue, most microorganisms have primarily a single tissue tropism.
Viral affinity for specific cells and tissue is largely based on viral surface structures with receptors present on the surface of the host cell. Other factors that affect tissue specificity include local temperature and pH levels, physical barriers and host defenses. Given the right environment, pathogenic microorganisms can cause serious infection or disease.