Origin and Distribution of HIV-1 Subtypes

Abstract

DefinitionHIV-1 displays a high genetic diversity that can be classified into clades, called subtypes. HIV-1 subtypes represent separate epidemics with independent evolutionary histories that occasionally overlap to generate recombinant forms. The stratification of HIV-1 strains into subtypes and circulating recombinant forms (CRFs) is useful to study the impact of HIV-1 genetic diversity on pathogenesis, disease progression, treatment including resistance development, molecular epidemiology, and vaccine design. Furthermore, such a classification provides a way to monitor the evolution of different subtype epidemics, its geographic distribution, and its spread across countries, continents, and risk groups.HIV Genetic DiversityHIV accumulates mutations at an alarming rate, mainly due to its error-prone replication cycle, vast virus burden, and high recombination rate. This fast evolution allows the virus to adapt quickly upon attack by the immune system and to resist drug treatment and, ...