RT Journal Article SR Electronic(1) A1 Sugauchi, Fuminaka A1 Kumada, Hiromitsu A1 Acharya, Subrat A. A1 Shrestha, Santosh Man A1 Gamutan, Maria Teresita A. A1 Khan, Mobin A1 Gish, Robert G. A1 Tanaka, Yasuhito A1 Kato, Takanobu A1 Orito, Etsuro A1 Ueda, Ryuzo A1 Miyakawa, Yuzo A1 Mizokami, MasashiYR 2004 T1 Epidemiological and sequence differences between two subtypes (Ae and Aa) of hepatitis B virus genotype A JF Journal of General Virology, VO 85 IS 4 SP 811 OP 820 DO https://doi.org/10.1099/vir.0.79811-0 PB Microbiology Society, SN 1465-2099, AB Complete nucleotide sequences of 19 hepatitis B virus (HBV) isolates of genotype A (HBV/A) were determined and analysed along with those of 20 previously reported HBV/A isolates. Of the 19 HBV/A isolates, six including three from Japan and three from the USA clustered with the 14 HBV/A isolates from Western countries. The remaining 13 isolates including four from The Philippines, two from India, three from Nepal and four from Bangladesh clustered with the six HBV/A isolates reported from The Philippines, South Africa and Malawi. Due to distinct epidemiological distributions, genotype A in the 20 HBV isolates was classified into subtype Ae (e for Europe), and that in the other 19 into subtype Aa (a for Asia and Africa) provisionally. The 19 HBV/Aa isolates had a sequence variation significantly greater than that of the 20 HBV/Ae isolates (2·5±0·3 % vs 1·1±0·6 %, P<0·0001); they differed by 5·0±0·4 % (4·1–6·4 %). The double mutation (T1762/A1764) in the core promoter was significantly more frequent in HBV/Aa isolates than in HBV/Ae isolates (11/19 or 58 % vs 5/20 or 25 %, P<0·01). In the pregenome encapsidation (ε) signal, a point mutation from G to A or T at nt 1862 was detected in 16 of the 19 (84 %) HBV/Aa isolates but not in any of the 20 HBV/Ae isolates, which may affect virus replication and translation of hepatitis B e antigen. Subtypes Aa and Ae of genotype A deserve evaluation for any clinical differences between them, with a special reference to hepatocellular carcinoma prevalent in Africa., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.79811-0