Subtype distribution among intravenous drug users with chronic type C hepatitis in southern Spain.

The hepatitis C virus (HCV) subtype distribution among intravenous drug users (IVDU), and patients without this risk of acquiring HCV infection, was evaluated. The patients included in the study were 51 with chronic type C hepatitis (36 IVDU and 25 coinfected by HIV-1), and 31 on haemodialysis. Genotyping was performed on 71 viraemic patients, with the following distribution: 25.4%, 1a; 54.9%, 1b; 8.5%, 3a; 7%, mixed (1a, 1b; 3a, 1a; 3a, 1b; 2 x 3a, 2a); 1.4%, 4; and 2.8%, non-typeable. When subtypes were related to IVDU practice, the statistical significance was p < 0.01 for subtypes 1a (48.5% vs 7.5%, for IVDU and non-IVDU, respectively) and 1b (16.1% vs 85.1%). No relation between HIV-1 coinfection and subtype distribution was observed among IVDU patients. The results suggest that among young IVDU of Southern Spain the emerging HCV subtype is 1a.