Opportunistic Parasitism: Parasitic Association with the Host that has Compromised Immune System

Abstract

A symbiotic association between opportunistic parasites and immunocompromised hosts is known as opportunistic parasitism. The abnormality of immunity is caused by different factors: Aging enhances susceptibility to severe infections; malnutrition has significant depressing consequences for immune function; an immunosuppressant substance alcohol can interfere with the functions of many of the cells and molecules those are components of the immune system; infectious pathogens are also major causal agents of immunosuppression. Combined effect of these factors makes the host to be susceptible for opportunistic parasitic infections. In this review the promising factors which induce immune disorder and exemplary opportunistic parasitic infections which illustrate the real sense of opportunistic parasitism are well discussed.