The three clusters A, B and C (bold letters) are based on a similarity cut-off of 95% (Dotted line; Dice coefficient, represented by UPGMA, 1.0% optimization and 1.5% tolerance). The geographical location, year of disease onset, serogroup, serotype and multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) results are given for each V. cholerae isolate. Regional three-letter codes: ASH, Ashanti region; CEN, Central region; GAR, Greater Accra region; VOL, Volta region. District three-letter codes: AAN, Asante Akim North; ACC, Accra; ADE, Adentan; AGW, Agona-Swedru; AWS, Awutu-Senya; ASA, Ashaiman; GAE, Ga East; GAS, Ga South; GAW, Ga West; GOE, Gomoa East; GOW, Gomoa West; HOH, Hohoe; HOV, Ho; KPK, Kpone-Katamanso; LEK, Ledzekuku-Krowor; TEM, Tema.