Figure 3. Neighbor-joining phylogenetic tree of a 348-bp section of the viral capsid protein 1//2A junction region of hepatitis A virus (HAV) constructed by using the Kimura 2-parameter distance model. Place of infection (A), migration background (B), and age of case-patients (■, 0–9 y; ■■, 10–19 y; ■■■, 20–39 y; ■■■■, 40–59 y; ■■■■■, >60 y) (C) are shown for each HAV isolate. Linked cases as judged by health departments are indicated by brackets. HAV subgenotypes are indicated by roman numerals and letters. Scale bar indicates nucleotide substitutions per site.