Prevalence of infection with hepatitis C virus in Venezuela, as assessed with an immuno-assay based on synthetic peptides

Decreasing prevalence of Hepatitis B and absence of Hepatitis C Virus infection in the Warao indigenous population of Venezuela

Prevalence and molecular epidemiology studies for hepatitis B (HBV) and C (HCV) virus are scarce in Warao Amerindians from Venezuela, where an epidemic of human immunodeficiency virus type 1 (HIV-1) has recently been documented. To carry out a molecular epidemiology analysis of hepatitis B (HBV) and C (HCV) virus in Warao individuals from the Delta Amacuro State of Venezuela. A total of 548 sera were tested for serological and molecular markers for HBV and HCV. The prevalence of active infection (presence of HBV surface antigen, HBsAg), exposure to HBV (presence of Antibody to HBV core antigen, anti-HBc) and anti-HCV, was 1.8%, 13% and 0% respectively. HBV exposure was significantly lower in men below 18 years old and also lower than rates previously reported in other Amerindian communities from Venezuela. Thirty one percent (31%, 25/80) of individuals without evidence of HBV infection exhibited anti-HBs titer ≥ 10U.I / ml, being significantly more frequent in individuals younger than 20 years. A higher HBV exposure was observed among HIV-1 positive individuals (33% vs 11%, p <0.005). A high prevalence of occult HBV infection was also observed (5.6%, 11/195). Phylogenetic analysis of S gene and complete HBV genomes showed that F3 is the only circulating subgenotype, different from the F2 subgenotype found in 1991 in this population. These results suggest a recent introduction of subgenotype F3, with a low divergence among the isolates. These results highlight the importance of molecular epidemiology studies for viral control, and support the effectiveness of vaccination in reducing transmission of HBV.

Prevalence of amino acid mutations in hepatitis C virus core and NS5B regions among Venezuelan viral isolates and comparison with worldwide isolates

BACKGROUND

Recent reports show that R70Q and L/C91M amino acid substitutions in the core from different hepatitis C virus (HCV) genotypes have been associated with variable responses to interferon (IFN) and ribavirin (RBV) therapy, as well to an increase of hepatocellular carcinoma (HCC) risk, liver steatosis and insulin resistance (IR). Mutations in NS5B have also been associated to IFN, RBV, nucleoside and non-nucleoside inhibitors drug resistance. The prevalence of these mutations was studied in HCV RNA samples from chronically HCV-infected drug-naïve patients.

METHODS

After amplification of core and NS5B region by nested-PCR, 12 substitutions were analyzed in 266 Venezuelan HCV isolates subtype 1a, 1b, 2a, 2c, 2b, 2j (a subtype frequently found in Venezuela) and 3a (n = 127 and n = 228 for core and NS5B respectively), and compared to isolates from other countries (n = 355 and n = 646 for core and NS5B respectively).

RESULTS

R70Q and L/C91M core substitutions were present exclusively in HCV G1b. Both substitutions were more frequent in American isolates compared to Asian ones (69% versus 26%, p < 0.001 and 75% versus 45%, p < 0.001 respectively). In Venezuelan isolates NS5B D310N substitution was detected mainly in G3a (100%) and G1a (13%), this later with a significantly higher prevalence than in Brazilian isolates (p = 0.03). The NS5B mutations related to IFN/RBV treatment D244N was mainly found in G3a, and Q309R was present in all genotypes, except G2. Resistance to new NS5B inhibitors (C316N) was only detected in 18% of G1b, with a significantly lower prevalence than in Asian isolates, where this polymorphism was surprisingly frequent (p < 0.001).

CONCLUSIONS

Genotypical, geographical and regional differences were found in the prevalence of substitutions in HCV core and NS5B proteins. The substitutions found in the Venezuelan G2j type were similar to that found in G2a and G2c isolates. Our results suggest a high prevalence of the R70Q and L/C91M mutations of core protein for G1b and D310N substitution of NS5B protein for the G3a. C316N polymorphism related with resistance to new NS5B inhibitors was only found in G1b. Some of these mutations could be associated with a worse prognosis of the disease in HCV infected patients.

Genetic history of hepatitis C virus in Venezuela: high diversity and long time of evolution of HCV genotype 2

BACKGROUND

The subtype diversity of the hepatitis C virus (HCV) genotypes is unknown in Venezuela.

METHODOLOGY/PRINCIPAL FINDINGS

Partial sequencing of the NS5B region was performed in 310 isolates circulating in patients from 1995 to 2007. In the samples collected between 2005 and 2007, HCV genotype 1 (G1) was the most common genotype (63%), composed as expected of mainly G1a and G1b. G2 was the second most common genotype (33%), being G2a almost absent and G2j the most frequent subtype. Sequence analysis of the core region confirmed the subtype assignment performed within the NS5b region in 63 isolates. The complete genome sequence of G2j was obtained. G2j has been described in France, Canada and Burkina Fasso, but it was not found in Martinique, where several subtypes of G2 circulate in the general population. Bayesian coalescence analysis indicated a most recent common ancestor (MRCA) of G2j around 1785, before the introduction of G1b (1869) and G1a (1922). While HCV G1a and G1b experienced a growth reduction since 1990, coincident with the time when blood testing was implemented in Venezuela, HCV G2j did not seem to reach growth equilibrium during this period.

CONCLUSIONS/SIGNIFICANCE

Assuming the introduction of G2j from Africa during the slave trade, the high frequency of G2j found in Venezuela could suggest: 1- the introduction of African ethnic groups different from the ones introduced to Martinique or 2- the occurrence of a founder effect. This study represents an in-depth analysis of the subtype diversity of HCV in Venezuela, which is still unexplored in the Americas and deserves further studies.