Human immunodeficiency virus (HIV) is a single-stranded ribonucleic acid (RNA) virus recognized as the causative agent of acquired immunodeficiency syndrome (AIDS)
Types of HIV epidemics:
Low-level epidemic is when HIV may have existed for many years but has never spread to significant levels in any sub-population; recorded infection is largely confined to high-risk individuals (eg drug injectors, sex workers, men having sex with other men [MSM]); HIV prevalence has not consistently exceeded 5% in any sub-population
Concentrated HIV epidemics is when HIV has spread rapidly in a defined sub-population but is not well established in the general population; HIV prevalence is consistently >5% in at least one sub-population but is <1% in pregnant women in urban areas
Generalized HIV epidemic is when HIV is firmly established in the general population; HIV prevalence is consistently >1% in pregnant women
Pathophysiology
The outer viral membrane which contains HIV-specific glycoproteins (gp) including gp120 and gp41, facilitates attachment and entry of HIV into the host's CD4+ cells
CD4+ T cell destruction is the hallmark of HIV infection
Viral replication progresses with the presence of two key enzymes: Reverse transcriptase and integrase
Reverse transcriptase: Forms viral RNA to viral DNA
Integrase: Transports viral DNA into the nucleus to integrate with human chromosomal DNA
B cell proliferation and abnormal antibody production impairs humoral immunity
Ongoing viremia with pro-inflammatory cytokines, B cell proliferation, and hypergammaglobulinemia leads to a chronic inflammatory state that contributes to cardiovascular disease, cancer, and other chronic diseases
