Introduction: The hepatitis B virus (HBV) is characterized by significant genotypic heterogeneity. Circulating genotypes in Congo are not all known. The purpose of this work is to establish a national genotypic mapping of HBV.

Patients and Methods: Descriptive, cross-sectional study carried out in the blood transfusion centers and integrated health centers of the Congo departments, from 1 January 2010 to 31 December 2016. Asymptomatic, blood donor or consulting patients formed the study population. The search for HBsAg was carried out by rapid tests, supplemented by a discriminatory screening test by the ELISA technique ; then detection of the HBV viral DNA by nested PCR on the HBPol region of the PreS1 / PreS2 / HBsAg domains of the S gene, using the HBPr1 / HBPr135 and HBPr2 / HBPr3 primer pairs and determination of the genotypes by sequencing from PCR product.

Results: A total of 3017 patients with mean age of 39 +/- 16 years were included, including 1576 men and 1440 women. Of these, 379 (12.5%) were positive for HBsAg. Of these 379 samples submitted to the molecular study, 321 (84%) were positive for HBV viral DNA. The genotypes found were genotype E (n = 207, 54.6%), A (n = 88, 23.2%), D (n = 4, 1%), B (n = 1, 0.3). %), B / C (n = 1, 0.3%) and C (n = 1, 0.3%). In 19 cases (5%) the genotype
could not be determined. The identified subgenotypes were A3 and A6 for genotype A and D7 for genotype D. The distribution of genotypes was almost homogeneous across all departments. Genotype D was only identified in one department, as were genotypes B and C in only one other department.

Conclusion: Genotypes E and A are the most common in our country. The presence of genotypes D, B and C is probably related to population migrations. Subgenotypes A3, A6 and D7 were the only ones identified in our work.