Antigenic Diversity of Hepatitis B Virus Strains of Genotype F in Amerindians and Other Population Groups from Venezuela

Abstract

The adw4 subtype of hepatitis B virus (HBV) belongs to a unique genomic group (genotype F) representing the original HBV strains from the New World. Data regarding the prevalence of this subtype among HBV carriers in South America are, however, scarce, and those concerning HBV genotype F are based on only a few samples from Latin America. In this study, serum samples were obtained from 141 hepatitis B surface antigen (HBsAg) carriers from Amerindians and urban populations from Venezuela. The HBsAg subtype was identified with monoclonal antibodies in 105 samples, and the HBV genotype was identified by reverse-phase hybridization with DNA fragments in 58 samples. The adw4 subtype was highly prevalent in the population studied (75%); among the Amerindians, the prevalence was 97%. The adw2 subtype was also present (10%), while other subtypes (ayw3 and ayw4) were only occasionally found. The HBV subtype was associated with the expected genotype in most cases (80%), and thus genotype F was highly prevalent. Sequencing of viral strains that gave genotypes unpredicted by the HBsAg subtyping confirmed seven of them as belonging to not previously described genotype-subtype associations: namely, adw2 and ayw4 within genotype F.

Nomenclature for antiviral-resistant human hepatitis B virus mutations in the polymerase region

“…Genotype A is found world-wide; genotypes B and C are most predominant in Asia; genotype D is found in South Europe, the Americas, and Australia; genotype E is most commonly found in Africa; genotype F is found in native Americans and Polynesians; and genotype G is found in the United States and Europe. 33,34 Typical characteristics of prototype members of the different viral genotypes are shown in Table 1, which includes differences in the length of hepatitis B core antigen (HBcAg) and preS1 region. Because the carboxyterminal portion of HB-cAg and the complete open reading frame (ORF) of the surface gene (preS1, preS2, and hepatitis B surface antigen [HB-sAg]) overlap with polymerase, these length polymorphisms affect the total length of the polymerase protein (Table 1).…”

Clade analysis and surface antigen polymorphism of hepatitis B virus American genotypes

“…HBV genotype G has recently been described and its distribution is not yet fully known [Stuyver et al, 2000]. HBV genotype F is autochthonous to South America and highly predominant in the region, particularly in Venezuela [Blitz et al, 1998]. A new genotype, HBV genotype H, has been recently found in Central America and is closely related to HBV genotype F [Arauz-Ruiz et al, 2002].…”

Clinical relevance of viral dynamics and genotypes in hepatitis B virus

“…1). 24,[27][28][29][30] Genotype A can be regarded as pandemic but is most commonly found in northern Europe, North America and Central Africa, while genotype B predominates in Asia (China, Indonesia and Vietnam). Genotype C is found in the Far East in Korea, China, Japan and Vietnam as well as the Pacific rim and Island Countries, while genotype D, which is also more or less pandemic, is found in the Mediterranean countries, the Middle East extending to India, North America and parts of the Asia-Pacific region.…”