7 WORLD GASTROENTEROLOGY NEWS JANUARY 2015 Editorial | Expert Point of View | Gastro 2015: AGW/WGO | WDHD News | WGO & WGOF News | WGO Global Guidelines | Calendar of Events HIV/HBV and HIV/HCV Co-infection in Sub-Saharan Africa: Transmission, Disease Outcomes, and Treatment Options Mark W. Sonderup, MD Senior Consultant Hepatologist, Division of Hepatology Department of Medicine, Faculty of Health Sciences University of Cape Town Cape Town, South Africa Introduction Liver disease, particularly in the post antiretroviral era of HIV/AIDS, has emerged as a major cause of mor-bidity and mortality in Hepatitis B (HBV) or Hepatitis C (HCV) co-infected patients1-4. Sub-Saharan Africa, an epicenter of HIV infection, comprises 11% of the global population, but 70% of those infected with HIV. This translates to 24 million HIV infected individu-als in a region that is simultaneously highly endemic for hepatitis B with an estimated >8% population preva-lence or some 65 million people. The population prevalence data for hepati-tis C is limited for most sub-Saharan African regions, however it is estimat-ed that almost 30 million are infected. In contrast to developed countries, HBV co-infection outnumbers HCV co-infection in sub-Saharan Africa and probably reflects the low preva-lence of injecting drug use (IDU). Rates of co-infection with hepatitis B of up to 36% are reported with the highest rates recorded in West and Southern sub-Saharan Africa5. Transmission and acquisition of HIV, Hepatitis B and Hepatitis C in sub-Saharan Africa In sub-Saharan Africa, HIV and HBV transmission occurs mostly indepen-dent of each other with HBV infec-tions usually occurring via horizontal transmission before the age of 5 and HIV heterosexually acquired during adulthood. However, HIV and hepa-titis B may share routes of acquisition in neonates as a result of perinatal mother-to-child transmission. Mater-nal HIV infection increases mother-to- child transmission up to 2.5 fold as HIV promotes Hepatitis B replication and HIV/HBV co-infected mothers are more likely to be HBeAg positive and are thus potentially more infec-tious leading to increased perinatal transmission risk6. As opposed to IDU, the predomi-nant mode of HCV transmission in sub-Saharan Africa is thought to be iatrogenic via inadequate screen-ing of blood products or the reuse of syringes in health care facilities. AlthoughHIV is thought to increase the risk of vertical HCV transmission 2.8 fold, studies suggest low rates of <5% vertical HCV transmission in sub-Saharan Africa 7, 8. Hepatitis B and Hepatitis C genotype distribution Genotypes A, D and E are the pre-dominant hepatitis B genotypes in Africa. Genotype A accounts for up to 90% of HBV infections in south-ern, eastern and central Africa with genotype E occurring in West Africa. Genotype D occurs mainly in North Africa9. Genotype A predisposes to chronicity with an elevated risk of hepatocellular carcinoma, but is also more responsive to alpha-interferon treatment. Genotype D is associated with reduced response rates to alpha-interferon and with acute infection, is associated with an increased risk of fulminant hepatitis. Hepatitis C Genotypes 1, 2, 4 and 5 have endemic origins in Africa. Hepatitis C Genotypes 1 and 2 occur throughout Africa with Genotype 4 occurring in Egypt and parts of Central Africa. Genotype 5 occurs in Southern Africa and less commonly, in some parts of Central Africa. Outcomes of HIV/HBV and HIV/ HCV co-infection HIV promotes chronicity of infection, liver fibrosis and increases the risk of hepatocellular carcinoma in both chronic hepatitis B and C, particularly in the clinical setting of low CD4 counts1-4. HIV co-infection augments the risk of reactivation or sero-reversion of hepatitis B. In adult-acquired hepati-tis B infection, concurrently acquired or existing HIV infection increases C. Wendy Spearman, MD Head: Division of Hepatology Department of Medicine, Faculty of Health Sciences University of Cape Town Cape Town, South Africa
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