Hepatitis C virus genotypes: An investigation of type-specific differences in geographic origin and disease

Abstract

Because of the nucleotide sequence diversity of different isolates of hepatitis C virus, it has become important to clarify whether distinct genotypes of hepatitis C virus vary with respect to pathogenicity, infectivity, response to antiviral therapy and geographic clustering. We assessed nucleotide sequence variability in the 5' noncoding region of hepatitis C virus, using restriction enzymes to analyze the distribution of hepatitis C virus genotypes, in 80 patients with chronic hepatitis C virus infection. Genotypes were correlated with demographic, clinical and histological features. Thirty-seven patients were infected with type 1, 10 had type 2 and 8 had type 3, and another 23 were infected with a new distinct hepatitis C virus type now classified as type 4. Two were infected with variants whose classification are uncertain. Types 1, 2 and 3 were found in patients from the United Kingdom, southern Europe, Asia, Africa and South America. Nineteen of 23 type 4 genotype isolates were from Middle Eastern patients, compared with 0 of 37 type 1 isolates (p < 0.001). Of 21 Middle Eastern patients, 19 (90.4%) had type 4 hepatitis C virus (p = 0.001, odds ratio = 9). We found no significant difference between the mean ages or mean serum aminotransferase concentrations between the various types. Types 1, 2, 3 and 4 were found in patients with mild-to-moderate disease or severe disease. However, 21 of 29 (72.4%) patients with type 1 who underwent liver biopsy had severe chronic hepatitis, cirrhosis or hepatocellular carcinoma histologically; 8 had mild or moderate chronic hepatitis without cirrhosis (p = 0.03, odds ratio = 2.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroid Disease in Chronic Hepatitis C Infection Treated With Combination Interferon-a and Ribavirin: Management Strategies and Future Perspective

“…6 The evolution of various genotypes is influenced by infection patterns, population migration, immune selection, and replication efficiency. 7,8 …”

Geographic integration of hepatitis C virus: A global threat

“…However, while some genotypes are ubiquitous, others are found only in specific regions, where they exhibit a high diversity of subtypes (Figure 2). This distribution pattern and the antigenic and biological differences between the HCV types point to long periods of endemic infection during which there was no significant exchange with types from other regions[42]. …”

“…In North America, parts of South America, United Kingdom, Scandinavia and Australia, 1a is the most prevalent subtype[42]. In Greece, Poland and the Netherlands, subtype 3 is responsible for 30% of all cases, and in Russia and the Baltic States, subtypes 1b and 3a share dominance[48].…”

HCV Genome-Wide Genetic Analyses in Context of Disease Progression and Hepatocellular Carcinoma

“…Other associations between HCV genetic variation and pathology are less well accepted. Some studies found little evidence for virulence differences between the major HCV genotypes [39], [40], but most studies found differences, such as genotype 1 being more virulent than genotype 2 [41], [42]. Most studies have found genotype 1b to be more virulent and more highly associated with HCC than other genotypes [43]–[47].…”