Molecular Genetic Diversity of Hepatitis B Virus in Kenya

Mwangi, Joseph; Ng’ang’a, Zipporah; Songok, Elijah; Kinyua, Joyceline; Lagat, Nancy; Muriuki, Joseph; Lihana, Raphael; Khamadi, Samoel; Osman, Saida; Lwembe, Raphael; Kiptoo, Michael; Mwau, Matilu; Chirchir, Ruth; Mpoke, Solomon; Nyamongo, Jack; Okoth, Fred; Yamada, Ryuji; Kageyama, Seiji; Ishiguro, Hiroshi

doi:10.1159/000205526

Cited by 24 publications

(28 citation statements)

References 35 publications

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“…Phylogenetic analysis showed presence of HBV genotypes A (78%) and D (22%) in the Ethiopian population, with genotype A being predominant. This is consistent with previous studies of HBV genotype distribution in neighboring countries and other regions of Africa [Norder et al, ; Kramvis and Kew, ; Mwangi et al, ; Mahgoub et al, ; Kwange et al, ; Yousif et al, ]. Although, genotype E has been reported in some east‐African countries we did not find genotype E in Ethiopia.…”

Section: Discussionsupporting

confidence: 93%

Molecular epidemiology and genetic diversity of hepatitis B virus in Ethiopia

Hundie¹,

Raj²,

Michael

et al. 2015

Journal of Medical Virology

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Although hepatitis B virus (HBV) infection is hyperendemic in Ethiopia and constitutes a major public health problem, little is known about its genetic diversity, genotypes, and circulation. The aim of this study was to determine the molecular epidemiology and genetic diversity of HBV in Ethiopia, using 391 serum samples collected from HBsAg-positive blood donors living in five different geographic regions. The HBV S/pol gene was amplified, sequenced, and HBV genotypes, subgenotypes, serotypes, and major hydrophilic region (MHR) variants were determined. Phylogenetic analysis of 371 samples (95%) revealed the distribution of genotypes A (78%) and D (22%) in Ethiopia. Further phylogenetic analysis identified one subgenotype (A1) within genotype A, and 4 subgenotypes within genotype D (D1; 1.3%, D2; 55%, D4; 2.5%, and D6; 8.8%). Importantly, 24 isolates (30%) of genotype D formed a novel phylogenetic cluster, distinct from any known D subgenotypes, and two A/D recombinants. Analysis of predicted amino-acid sequences within the HBsAg revealed four serotypes: adw2 (79%), ayw1 (3.1%), ayw2 (7.8%), and ayw3 (11.6%). Subsequent examination of sequences showed that 51 HBV isolates (14%) had mutations in the MHR and 8 isolates (2.2%) in the reverse transcriptase known to confer antiviral resistance. This study provides the first description of HBV genetic diversity in Ethiopia with a predominance of subgenotypes A1 and D2, and also identified HBV isolates that could represent a novel subgenotype. Furthermore, a significant prevalence of HBsAg variants in Ethiopian population is revealed.

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Section: Discussionsupporting

confidence: 93%

Molecular epidemiology and genetic diversity of hepatitis B virus in Ethiopia

Hundie¹,

Raj²,

Michael

et al. 2015

Journal of Medical Virology

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“…Previous studies have also shown that HBV/A is the main genotype endemic in Uganda [19], similar to other countries in East Africa like Kenya where 88% of HBV strains belong to genotype A [42]. This observation is in concert with the HBV genotype divide, with HBV/E dominating in the west and HBV/A in the east of Africa [41,43].…”

Section: Discussionsupporting

confidence: 54%

Disparate distribution of hepatitis B virus genotypes in four sub-Saharan African countries

Forbi¹,

Ben-Ayed²,

Xia³

et al. 2013

Journal of Clinical Virology

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Background Hepatitis B virus (HBV) places a substantial health burden on Africa. Here, we investigated genetic diversity of HBV variants circulating in 4 countries of sub-Saharan Africa using archived samples. In total, 1492 plasma samples were tested from HIV-infected individuals and pregnant women, among which 143 (9.6%) were PCR-positive for HBV DNA (Côte d’Ivoire, 70/608 [11.5%]; Ghana, 13/444 [2.9%]; Cameroon, 33/303 [10.9%]; and Uganda, 27/137 [19.7%]). Study design/results Phylogenetic analysis of the S-gene sequences identified HBV genotypes E (HBV/E, n = 96) and A (HBV/A, n = 47) distributed as follows: 87% of HBV/E and 13% of HBV/A in Côte d’Ivoire; 100% of HBV/E in Ghana; 67% of HBV/E and 33% of HBV/A in Cameroon; and 100% of HBV/A in Uganda. The average and maximal nucleotide distances among HBV/E sequences were 1.9% and 6.4%, respectively, suggesting a greater genetic diversity for this genotype than previously reported (p < 0.001). HBV/A strains were classified into subgenotypes HBV/A1, HBV/A2 and HBV/A3. In Uganda, 93% of HBV/A strains belonged to HBV/A1 whereas HBV/A3 was the only subgenotype of HBV/A found in Cameroon. In Côte d’Ivoire, HBV/A strains were classified as HBV/A1 (11.1%), HBV/A2 (33.3%) and HBV/A3 (55.6%). Phylogeographic analysis of the sequences available from Africa supported earlier suggestions on the origin of HBV/A1, HBV/A2 and HBV/A3 in East, South and West/Central Africa, respectively. Using predicted amino acid sequences, hepatitis B surface antigen (HBsAg) was classified into serotype ayw4 in 93% of HBV/E strains and adw2 in 68% of HBV/A strains. Also, 7.7% of the sequences carried substitutions in HBsAg associated with immune escape. Conclusions The observations of pan-African and global dissemination of HBV/A1 and HBV/A2, and the circulation of HBV/E and HBV/A3 almost exclusively in West and Central Africa suggest a more recent increase in prevalence in Africa of HBV/E and HBV/A3 compared to HBV/A1 and HBV/A2. The broad genetic heterogeneity of HBsAg detected here may impact the efficacy of prevention and control efforts in sub-Saharan Africa.

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“…Only 4 complete subgenotype A2 genomes from South Africa have been deposited in GenBank. Shorter subgenomic sequences of subgenotype A2 from South Africa ( 32 ), Tunisia ( 33 ), and Kenya ( 34 ) have also been deposited. More extensive molecular epidemiologic studies in Africa might uncover a higher circulation of subgenotype A2 in more remote regions.…”

Section: Discussionmentioning

confidence: 99%

Occult Hepatitis B Virus Infection in Chacma Baboons, South Africa

Dickens

Kew²,

Purcell³

et al. 2013

Emerg. Infect. Dis.

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During previous studies of susceptibility to hepatitis B virus (HBV) infection, HBV DNA was detected in 2/6 wild-caught baboons. In the present study, HBV DNA was amplified from 15/69 wild-caught baboons. All animals were negative for HBV surface antigen and antibody against HBV core antigen. Liver tissue from 1 baboon was immunohistochemically negative for HBV surface antigen but positive for HBV core antigen. The complete HBV genome of an isolate from this liver clustered with subgenotype A2. Reverse transcription PCR of liver RNA amplified virus precore and surface protein genes, indicating replication of virus in baboon liver tissue. Four experimentally naive baboons were injected with serum from HBV DNA–positive baboons. These 4 baboons showed transient seroconversion, and HBV DNA was amplified from serum at various times after infection. The presence of HBV DNA at relatively low levels and in the absence of serologic markers in the baboon, a nonhuman primate, indicates an occult infection.

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Molecular Genetic Diversity of Hepatitis B Virus in Kenya

Cited by 24 publications

References 35 publications

Molecular epidemiology and genetic diversity of hepatitis B virus in Ethiopia

Molecular epidemiology and genetic diversity of hepatitis B virus in Ethiopia

Disparate distribution of hepatitis B virus genotypes in four sub-Saharan African countries

Occult Hepatitis B Virus Infection in Chacma Baboons, South Africa

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