Hepatitis C virus genotypes and viral ribonucleic acid titers in Nigeria

Abstract

Background and Objectives: Hepatitis C virus (HCV) is a major cause of chronic liver disease, cirrhosis and hepatocellular cancer worldwide, with associated significant morbidity and mortality. It is estimated that 3% of the world population have HCV, and in Nigeria, prevalence rates of between 4.7-20% have been reported suggesting its endemicity in the country. HCV is classified into at least 6 genotypes, which determine the response to, and duration of treatment. Not much is known about this virus in Nigeria. This study aims to provide information on the prevalent HCV genotypes and viral load titers in Nigerian patients. Methods: A cross-sectional study using plasma from 100 serologically confirmed HCV positive patients from across Nigeria who accessed the Human Virology Laboratory, Nigerian Institute of Medical Research (NIMR), for HCV RNA viral load (HCVL) and HCV genotyping tests, from September 2010 to October 2012. Plasma (1000μL) collected from each individual was used to obtain HCVL using the automated COBASAmpliprep/TaqMan hepatitis C kit and the COBAS-Ampliprep/TaqMan instruments (Roche). Subsequently, HCV RNA qualitatitve assay was done with 200μL of plasma on the COBAS Amplicor analyzer using the COBAS Amplicor hepatitis C test kits. The amplicons (100μL) generated were used for genotyping with the aid of the LINEAR-ARRAY HCV genotyping and detection kits ( Roche). Results: Samples were from 74 males, 26 females, with a mean age of 36 years (±6.5). The range of HCV RNA titers obtained was from 39 – 6,380,000 IU/mL; median of 141,166 IU/mL. The genotypes found were 1, 3, 2, 4 and 6 with the following prevalence; 64.7%, 7.4%, 5.9%, 4.4%, and 2.9% respectively. Genotype 5 was absent from the cohort. Dual genotypes were found in 14.7%, and 32 samples were excluded from genotype analysis due to undetectable viral titers observed. Conclusion: The median viral titre in this study population was 141,166 IU/mL. Genotype 1 was the most prevalent and is one of the most difficult to treat HCV genotypes requiring 48 weeks of therapy. Since several genotypes were observed, it is pertinent that genotype be determined before commencing treatment.

Keywords: Genotype, hepatitis C virus, hepatitis C viral load, Nigeria