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.

Multiple cytokine expression profiles reveal immune-based differences in occult hepatitis B genotype H-infected Mexican Nahua patients

“…Subjects -A previous, cross-sectional study conducted by our group revealed that OHB genotype H infection is common among members of the Nahua community (Roman et al 2010). In the present study, 41 sera samples from Nahua subjects were retrospectively analysed.…”

“…We have shown previously that OHB genotype H is common among the ethnic Nahua population (Roman et al 2010). Additionally, Mexico has been reported to be a low endemic area for HBV and there is a low association between HBV infection and HCC reported in the country (Roman et al 2010). These data may indicate that the natural course of liver diseases in the native populations of Mexico may be different from what is described in high endemic areas for HBV infection.…”

“…A total of 20 healthy Nahua donors (HBsAg-, HBVDNA-, anti-HBc-) were also studied. All patients were negative for antibodies to hepatitis C virus and human immunodeficiency virus (Roman et al 2010).…”

“…Clinical history and demographical data were collected from all participants by a structured questionnaire as previously reported (Roman et al 2010). Liver alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured in patient serum by an enzymatic method (Human, Wiesbaden, Germany) in an automated analyser.…”

“…Genotype H has been primarily detected in Mexico (Sanchez et al 2002(Sanchez et al , 2007. We have shown previously that OHB genotype H is common among the ethnic Nahua population (Roman et al 2010). Additionally, Mexico has been reported to be a low endemic area for HBV and there is a low association between HBV infection and HCC reported in the country (Roman et al 2010).…”