Incidental Detection of Parasites: A Pathologists Viewpoint

In biology, immunity is the capability of multicellular organisms to resist harmful microorganisms. Immunity involves both specific and nonspecific components. The nonspecific components act as barriers or eliminators of a wide range of pathogens irrespective of their antigenic make-up [1]. Other components of the immune system adapt themselves to each new disease encountered and can generate pathogen-specific immunity. Immunity is a complex biological system that can recognize and tolerate whatever belongs to the self, and to recognize and reject what is foreign non-self. The immune system has innate and adaptive components. Innate immunity is present in all metazoans, while adaptive immunity only occurs in vertebrates [2]. The innate component of the immunity system involves the recognition of certain foreign non-self-molecules to generate one of two types of innate immune responses: Inflammatory responses and phagocytosis. The adaptive component, on the other hand, involves more advanced lymphatic cells that can distinguish between specific non-self-substances in the presence of self. The reaction to foreign substances is etymologically described as inflammation while the non-reaction to self-substances is described as immunity. The two components of the immune system create a dynamic biological environment where health can be seen as a physical state where the self is immunologically spared, and what is foreign is inflammatorily and immunologically eliminated. Disease can arise when what is foreign cannot be eliminated or what is self is not spared