Hepatitis B virus genotypes and subgenotypes and the natural history and epidemiology of hepatitis B.

Abstract Hepatitis B virus affects more than 270 million people worldwide, with about 78,000 deaths annually from complications of the disease. Espirito Santo State (ES) is located in the Southeast region of Brazil, with a current population of 4,108,508 million people, initially colonized by black people from Africa in the 16th century and by European immigrants, mainly Italians in the 19th /20th centuries. The aim of this study is to characterize the demographic, epidemiological, laboratory, virological (HBe/anti-HBe status, viral load, genotypes, subgenotypes,) and clinical aspects of 587 chronic HBV carriers followed up at the Hepatitis B Outpatient Clinic of the Infectious Diseases Service of the Cassiano Antonio de Moraes University Hospital, University of Espirito Santo (HUCAM/UFES). The most frequent genotype was A (132/65.3%) [A1 = 129 (63.9%) and A2 = 3 (1.5%)], followed by genotypes D (66/32.7%) [D3 = 56 (27.7%), D4 = 8 (4.0%) and D2 = 2 (1.0%)] and F (4/2.0%) - all subgenotype F2a. We did not observe an association between infections by subgenotypes A1 or D3 with age, sex, co-infection with HIV or HCV, viral load, antiviral usage, HBeAg status or clinical stages of chronic hepatitis B. An association was observed between the probable HBV transmission routes and the viral subgenotype: mother –to-child-transmission (MTCT) was associated with the subgenotype A1 and intrafamilial transmission with subgenotype D3. There was also a significant association between subgenotype and birthplace: subgenotype A1 was more frequent than subgenotype D3 among individuals born outside ES compared to individuals born in ES.