Figure 1.

Some features of the natural history of HIV infection. A) Approximate time course of HIV infection, with estimates of kinetics of viral load and CD4 count taken from longitudinal studies of acute or chronic infection (8, 10, 13). B) Typical time course of diversity (average pairwise distance between sequences) and divergence (percent genetic distance from first detected virus) of viral populations over the course of infection, with rates taken from Shankarappa et al (10). C) Maximum likelihood phylogenetic tree for viral sequences sampled over six years of infection (image taken from (14) under CCBY license, created with data from Patient 6 in (10)).