Pathogenesis of opportunistic infections

ABSTRACT

Opportunistic infections (OIs) are caused by a non-pathogenic microorganism in an immunocompromised individual. OIs causing organisms are bacteria, viruses, fungi, and parasites which are commonly present in the environment and also in immunocompetent individuals. These organisms become pathogenic and infectious when there is an imbalance between host immunity and virulence of the pathogen. Typically, the balance is maintained by our immune system which can be natural or acquired immunity. In human, natural immunity is inborn and pre-programmed at the time of birth, whereas the adaptive is stimulated naturally or by artificial means to build immunity and do the defense mechanism. The immunity is lost or reduced under certain circumstances includes genetic mutations, chromosomal abnormality, autoimmune destruction of immune cells, environmental predisposition damage to immune cells, specific infections which have tropism for the immune cells and destroy them, major trauma and injuries, nutritional deficiency and therapy for cancers with immunosuppressants. There are a few well-known conditions like Diabetes Mellitus, HIV, organ or bone marrow transplantation, covid-19 are at most risk for this OIs. Notably, patients who need to be started on prophylactic drugs to prevent OIs as the defense mechanism in the immune system is reduced and cause the non-pathogenic organism to grow in large number. Immunity in a host can be maintained by means of good control of infection with appropriate therapy for the above diseases. The conclusion is that immunity is the main weapon for an individual to protect against OIs as well the other infections which would help to lead a healthy normal life. © 2022 Nova Science Publishers, Inc.