Hepatitis B virus strains from Rwandan blood donors are genetically similar and form one clade within subgenotype A1

Abstract

BackgroundRwanda is a central African country with about 12 million inhabitants. The 1994 genocide against the Tutsi destroyed much of the infrastructure, including the health system. Although this has improved significantly, many challenges remain to be addressed. In this study, the prevalence of serological markers of past and ongoing hepatitis B virus (HBV) infection and HBV vaccine related immunity was investigated in samples from blood donors from all regions of Rwanda.MethodsThe results from hepatitis B surface antigen (HBsAg) analyses of all (45,061) blood donations collected countrywide in 2014 from 13,637 first time and 31,424 repeat blood donors were compiled. Samples from 581 HBsAg negative blood donors were selected for further analysis for antibodies against HBV, anti-HBs and anti-HBc. Additional 139 samples from HBsAg positive donors were analyzed for HBeAg/anti-HBe (132 samples) and for HBV DNA. The S-gene was amplified by PCR, products sequenced, and phylogenetic analysis was performed.ResultsHBsAg was found in 4.1% of first time donors with somewhat higher prevalence among those from the Central and Eastern regions than from other parts of the country. Indications of past infection was found in 21% of the HBsAg negative donors, 4.3% had only anti-HBs suggesting HBV vaccination. HBeAg was detected in 28 (21%), anti-HBe in 97 (73%), and both HBeAg and anti-HBe in 4 of 132 HBsAg positive donors. HBV DNA was found in 85 samples, and the complete S-gene was sequenced in 58 of those. Phylogenetic analysis of the sequences revealed that all HBV strains belonged to subgenotype A1, and formed one clade in the phylogenetic tree. In addition, 12 strains from first time donors had a unique 18 amino acid deletion in the N-terminal part of the pre-S2 region.ConclusionThis study indicated that the prevalence of hepatitis B is intermediate in Rwanda and that the vaccination coverage is relatively low in young adults. All surveyed Rwandan blood donors were infected with similar subgenotype A1 strains, and a high frequency of those with anti-HBe had detectable HBV DNA. Several strains had in addition a unique pre-S2 deletion, the virulence of which needs to be further studied.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-2149-z) contains supplementary material, which is available to authorized users.

Genetic and phylogenic characterization of hepatitis B virus in the eastern part of the Democratic Republic of Congo

“…Rwanda is probably located at the East of a demarcation zone dividing Africa in West and East zones where genotypes E and A1 predominate, respectively . This hypothesis is supported by our findings, by the paper published by Twagirumugabe et al, and by the fact that the only case of genotype E identified in our study was obtained from a 41‐year‐old woman newly established in Bukavu and who was originated from Kinshasa, a western town of the DRC.…”

“…In the Sub-Saharan Africa, genotype A is mainly found in the austral and southern part while genotype E is the major type observed in West Africa (Figure 1). 11,[12][13][14] Until now, only one study was performed in the DRC and only involving samples coming from the western part of the country. 12 Results of the present study are surprising in regard with the high diversity of genotypes found in the study conducted by Hübschen et al 19 Tanzania, and Kenya.…”

“…Results of the present study are surprising in regard with the high diversity of genotypes found in the study conducted by Hübschen et al and the variability of genotypes found in Rwanda, a neighboring country of the eastern part of the DRC. In a recent article published by Twagirumugabe et al among surveyed Rwandan blood donors, they reported that all sequenced strains (58) belonged to similar HBV subgenotype A1. In our study, almost all strains belonged to genotype A.…”

“…Despite this, these new data on the distribution of HBV genotype in an African region with no information are consistent with findings reported in previous studies. In the Sub‐Saharan Africa, genotype A is mainly found in the austral and southern part while genotype E is the major type observed in West Africa (Figure . Until now, only one study was performed in the DRC and only involving samples coming from the western part of the country .…”

“…In North America and Western Europe, the majority of infections are of genotype A whereas in Africa, the most predominant genotypes are A, D, and E. 8,11 In western Africa, genotype E predominates throughout a vast area from Senegal to Namibia (African genotype E crescent) while the genotype A is more frequently found in the eastern part of sub-Saharan Africa. 8,11,12,14 Located in central Africa, the Democratic Republic of Congo (DRC)…”