Unexpected high prevalence of hepatitis C virus genotype 4 in southern Spain

Background/Aims: A unusually high rate of HCV-infected individuals in whom the HCV genotype cannot be ascertained by means of single PCR and LIPA. procedures has recently been reported in our area. The aim of the present study was to investigate the epidemiological, clinical and molecular characteristics of these patients. Methods: Cross-sectional study Eighty anti-HCV-positive patients with chronic liver disease, 45 (56.25%) of them intravenous drug users, were included. HCV genotyping was carried out in all patients using commercial single PCR and LIPA procedures. Samples where no HCV RNA amplification and/or indeterminate HCV genotype were found mere also tested by means of a nested PCR, HCV viral load was measured in all patients. Results: HCV genotyping was not achieved in 23 (28.75%) individuals. No amplification of HCV RNA was found in 19 of them, and in four other cases the LIPA procedure did not allow identification of a distinct HCV genotype. After the use of nested PCR+LIPA, it was found that the HCV genotype 4 was found in 11 of those 23 individuals (47.82%), Ten of these 11 HCV genotype 4-harboring individuals mere intravenous drug users. The HCV viral load was lower in HCV genotype 4-harboring individuals than in those whom the genotypes 1, 2 or 3 were found (p<0.001). Conclusions: A high rate of HCV genotype 4-harboring cases has been found among HCV-infected individuals in Southern Spain. Had only single PCR been used, these individuals could have been wrongly regarded as non-viremic.