title: Occult hepatitis B in the genotype H-infected Nahuas and Huichol native Mexican population.
abstract: Mexico is considered to be a low endemic country for HBV infection. However, a high anti-HBc against a low hepatitis B surface antigen (HBsAg) seroprevalence is the reported characteristic of native Mexicans. HBV diagnosis and genotype distribution was examined in native populations (Nahuas and Huichol, n = 306), and compared to a non-native population (Mestizos, n = 17). Overall, 6% of the natives were positive for HBsAg and 33% had detectable anti-HBc. HBsAg prevalence was lower in Nahuas compared to Huichols (1.4% vs. 9.4%, P < 0.002). Occult hepatitis B was detected in 14.2% (41/289) of natives, who either tested positive (5.88%, 17/289 HBsAg-negative) or negative for anti-HBc marker (8%, 24/289 HBsAg-negative). Age-adjusted anti-HBc seroprevalence and HBsAg quantitation revealed a sub-optimal sensitivity of conventional immunoassays. Nahuas had HBV/H and Huichol had HBV/A as the predominant genotypes followed by genotypes D, C, B, A, and D, G and H, respectively. A less variable HBV/H was characteristic in Mestizos, compared to a much variable HBV/H identified among the Nahuas. In conclusion, these findings indicate a high HBV endemicity among native Mexican groups where occult B infection is common. The different distribution of HBV genotypes among natives suggests multiple reservoirs of HBV from which these genotypes spread into the local communities. High anti-HBc seroprevalence against a low HBsAg prevalence rate may be due to the limited sensitivity of the immunoassays for the detection of HBsAg that are available in Mexico and/or unknown immunogenetic characteristics of native Mexicans.
authors.affiliation: Department of Molecular Biology in Medicine, Civil Hospital of Guadalajara, Fray Antonio Alcalde, Health Sciences Centre, University of Guadalajara, Guadalajara, Jalisco, Mexico.
authors.forename: Sonia
authors.initials: S
authors.lastname: Roman
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Anis
authors.initials: A
authors.lastname: Khan
authors.forename: Fuat
authors.initials: F
authors.lastname: Kurbanov
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kato
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizokami
authors.forename: Arturo
authors.initials: A
authors.lastname: Panduro
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D002648:Child; D004279:DNA, Viral / Q000145:classification; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology*; D006510:Hepatitis B Antibodies / Q000097:blood; D006512:Hepatitis B Core Antigens / Q000235:genetics / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000235:genetics* / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D016036:Seroepidemiologic Studies; D012698:Serologic Tests / Q000379:methods
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens