Hepatitis B virus genetic diversity in Argentina: dissimilar genotype distribution in two different geographical regions; description of hepatitis B surface antigen variants.

BACKGROUND: The hepatitis B virus (HBV) molecular epidemiological data of Argentina are still scarce, since most of the previous analyses have been performed in the Metropolitan Region.
OBJECTIVES: To deepen the current molecular and epidemiological information about the geographical distribution of HBV genotypes and subgenotypes, and to describe the hepatitis B surface antigen (HBsAg) variants circulating in Argentina. STUDY
DESIGN: Eighty-eight Argentine partial HBsAg sequences from both the Northern and the Metropolitan Regions of the country were analyzed along with 67 Argentine HBV sequences existing in GenBank.
RESULTS: Phylogenetic and amino acid sequence analysis grouped the 88 samples as genotypes A (14.8%), D (21.6%) and F (63.6%). In the Northern Region, 44 out of the 48 sequences analyzed (91.7%) grouped as genotype F. Differently, in the Metropolitan Region, the 40 samples grouped as genotype F (30.0%), genotype D (42.5%), and genotype A (27.5%). An elevated proportion (14.8%) of the genomes presented mutations in the major hydrophilic region (MHR).
CONCLUSIONS: The different genotype distribution in both Argentine regions indicates that the epidemiological landscape of HBV infection appears to be the result of the diverse human migratory movements that have given shape to the present population. Our findings show that the prevalence of HBsAg variants is quite significant among the Argentine population.