Serologic markers and molecular epidemiology of HBV from an HIV infected cohort from Cameroon Tshifhiwa Magoro 1, Emmaculate Nongpang 2, Lufuno Mavhandu 1, Roland Ndip 2, Helen Kimbi 2, Pascal Bessong 1 1 HIV/AIDS and Global Health Research Programme, Department of Microbiology, University of Venda, Thohoyandou, South Africa 2 Department of Parasitology, Faculty of Science, University of Buea, Buea, Cameroon

Background and rationale Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) are of global public concern. Despite the availability of a safe and efficient HBV vaccine. The results of HBV infection varies widely among infected patients, response to antiviral treatment and disease progression may differ depending on the genotype of a patient (Singh et al., 2009). It is imperative to determine HBV genotypes to identify patients at great risk for disease progression to cirrhosis and the risk of HCC.

Background and rationale Occult HBV infection (presence of HBV DNA in the absence of HBsAg). Guidelines for the use of antiretroviral agents in HIV/HBV co-infected patients recommend combination therapy with a tenofovir (TDF) Plus lamivudine (3TC) or Emtricitabine. The majority of HIV-HBV co-infected patients therefore receive an anti-HBV lamivudine monotherapy that has been shown to lead to frequent emergences of drug resistance. This study was aimed at investigating the prevalence, genotypes, and to assess HBV Lamivudine resistance mutations in a Cameroon HIV infected population.

STUDY DESIGN

Study site and study participants Study population Outpatient clients of the Baptist Health Centre, Mutengene, Cameroon. The centre offers HIV treatment. Mutengeni Idenau Ekona Yoke Limbe

Laboratory procedures Ethical consideration Sample n=455 Plasma Serology Isolation of DNA HBsAg seropositive HBsAg seronegative HBeAg Anti- HBc Anti- HBs Occult infection DNA amplification Sequencing Genotyping Drug resistance mutation

Results and discussion Prevalence of hepatitis B virus serological markers in 455 study participants in Cameroon.

Why are children still infected? In subjects below the age of 15 years (1-14), 20.9% (9/43) of them were reactive for HBsAg. Of which 44.4% (4/9) were reactive for HBeAg (indicating high levels of infectiousness in this subset of participants). However, those who were found to be infected in the same age group, it might be due to vaccine escape mutants or did not receive the vaccine at all or they did not respond to HBV vaccine. 31.3% (5/16) of subjects reactive for HBeAg were women of child-bearing age. Vertical transmission is frequently observed in women with HBeAg.

Epidemiological risk factors and HBsAg seropositivity (univariate analysis )

Occult HBV infection Occult HBV infection was assessed in samples with a negative HBsAg serology, regardless of their anti-HBc and anti-HBs serology. The prevalence of occult HBV infection was 6.5% (20/310). 35% (7/20) of the samples which showed occult HBV DNA, were also negative for anti-HBc and anti-HBs markers. In most countries, blood is screened for HBsAg; however the techniques used vary widely. A study from Ghana showed that using particle agglutination or dipstick tests, 46 and 29% of viremic patients were missed, respectively.

Why only a fraction of HBsAg positive patients were positive for HBV DNA? HBV DNA was successfully amplified in 45.7% (48/105) of the HBsAg positive patients. HBsAg is a marker of active infection, so we expected to find HBV DNA in such patients

Two major genotypes: HBV genotype E (n=33; 71.7 %) ; HBV genotype A (n=13; 28.3 %). Genotype E Genotype A Genotypes

Lamivudine mutations Several mutations were observed in the polymerase region of seven patients only [ 15.2 % (7/46) ]. Note: Samples in RED- Lamivudine naïve Samples in Black- Lamivudine experienced as part of HIV treatment No mutations that can code for resistance to tenofovir and adenofovir were detected ETV-entecavir TBV-telbivudine FTC-emtricitabine

Limitations Sample size HBV vaccination history were not recorded during sample collection. HBV viral load Measuring the level of protection (anti-HBs plasma levels of ≥10 IU/ml).

Conclusion and recommendations The present study demonstrates that HBV infection is endemic in the study population, with genotype E dominating and HBV genotypic resistance to lamivudine exists in the studied population. The results also highlight the importance of screening for HBV resistance before HIV treatment. This data can contribute to the development of policies for screening programmes in Cameroon. The study also illustrated the need for occult HBV detection to be implemented even if anti-HBc and anti-HBs were negative especially in an endemic area, such as Cameroon.

Acknowledgements We are grateful to the study participants. University of Venda- funding. National Research Foundation. The entire team of HIV/AIDS and Global Health Research Programme at the University of Venda.

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