The burden of HCV in sub-Saharan Africa has been poorly studied, despite estimates indicating that the region harbors some of the highest viral hepatitis rates in the world. The 2013-2014 Demographic and Health Survey (DHS) of the Democratic Republic of the Congo (DRC) offered a unique opportunity to delineate the extent and characteristics of HCV infection in the country. Because the DHS is a nationally representative survey, we could estimate the national burden of infection in the DRC.
We extracted RNA from a subset of dried blood spots (DBS) collected during the DHS, including 1,009 adults at least 40 years of age, and performed high-throughput HCV viremia testing using the Abbott m2000 instrument (Abbott Molecular, Des Plaines, IL). The Abbott platform reliably identifies HCV RNA extracted from a 6mm punch from DBS prepared using 50uL of whole blood obtained from subjects with viral loads of at least 1,000 IU/mL and allows for high-throughput screening. HCV-positive samples underwent targeted sequencing for genotyping and phylogenetic analyses.
Eleven infections were identified; the country-wide prevalence of HCV viremia was 1.1% among adults ≥ 40 years of age and 5.3% among those with HIV infection. All successfully genotyped cases were due to genotype 4 infection. We identified a cluster of cases in one province, Kasai Occidental, all of which failed initial genotyping attempts. To explore this finding, we are performing additional sampling of adults in this region and employing alternate sequencing approaches.
HCV is common among adults in the DRC and disproportionately affects those living with HIV. Based on recent DRC population estimates, 100,000 to 200,000 adults older than 40 years of age may have active infection and be eligible for treatment. Additionally, there appears to be a cluster of HCV cases in one region with undetermined genotype. Previous sequence analysis of HCV samples obtained from this region of the DRC led to the identification of a novel and rare Genotype 7 strain of HCV. Phylogenetic analyses of these cases may provide further insight into the diversity and evolution of HCV in sub-Saharan Africa. Finally, DBS-based HCV testing represents a useful tool for defining the burden of HCV viremia and can be easily incorporated into population-based surveys.