DISTRIBUTION OF HEPATITIS-B VIRUS GENOTYPES IN 2 DIFFERENT PEDIATRIC POPULATIONS FROM ARGENTINA

Differences in pathogenesis and the probability of becoming a chronic carrier depend on the age at which hepatitis B virus (HBV) infection i s acquired, ranging from 82% in infants less than 6 months of age to 1 5 to 30% in older children. HBV genotypes from 22 pediatric patients f rom two areas that differ in prevalence have been determined. Phylogen etic analysis shows a clear difference between the genotype distributi on in Buenos Aires, a low-prevalence area, and that found in Gualeguay , Entre Bios, a high-prevalence area. While the analysis allocated the sequences in the Buenos Aires group to genotypes A (36%), D (9%), and F (55%), the Gualeguay group presented exclusively genotype A isolate s with very low nucleotide divergence, which suggests a strong founder viral population, The high prevalence of genotype F in the Buenos Air es group and its high intragroup heterogeneity agree with the American origin of this genotype.