Additionally, molecular surveillance can provide important information about the capacity of HCV lineages to cause disease. Molecular surveillance is a critical component of HCV outbreak investigations because tracking of infections is necessary for the identification of sources of infection and accurate identification of cases associated with transmission networks. Molecular surveillance of hepatitis C is of the utmost importance for identification of HCV transmission networks. This remarkable genetic variability is one of the main factors that have prevented the development of a successful vaccine. The molecular plasticity of HCV allows rapid rearrangement of the intrahost viral population under different selection pressures. The high mutation rate is characteristic of HCV replication, resulting in a high degree of intrahost genetic diversity. These genotypes exhibit a characteristic distribution : genotypes 1–3 are distributed worldwide, while genotypes 4 and 5 are mainly found in Africa and genotype 6 is endemic in Asia. Based on the nucleotide variability in the viral genome, seven HCV genotypes and multiple subtypes have been recognized ( Figure 1B). HCV molecular evolution plays an important role in virus transmission, dictating in many ways the outcome of disease and therapy. The neighbor joining tree was constructed using maximum composite likelihood nucleotide distances using MEGA replications for bootstrapping. Sequences from the NS5B region were chosen to illustrate the maximum diversity within a subtype.
The most common regions used for molecular analyses and genetic relatedness studies are highlighted ( B) HCV representative strains belonging to all seven genotypes and all different subtypes are depicted. Additionally, the cornerstone discoveries that have defined the pathway for viral characterization are presented and the importance of implementing advanced HCV molecular surveillance is highlighted. Here, we review molecular aspects associated with HCV transmission, as well as the most recent technological advances used for virus and host characterization. Importantly, implementation of comprehensive global databases and data mining are also needed for the proper study of the mechanisms responsible for HCV transmission. Therefore, HCV AMS requires the incorporation of host factors as an integral component of the algorithms used to monitor disease occurrence. Accounting for virulence is also important for HCV AMS and both viral and host factors contribute to the disease outcome. Therefore, implementation of HCV advanced molecular surveillance (AMS) is essential for disease control. Tracking HCV infections is crucial for the elucidation of routes of transmission in a variety of settings. This high degree of variability represents a challenge for the accurate establishment of genetic relatedness between cases and complicates the identification of sources of infection. HCV exploits complex molecular mechanisms, which result in a high degree of intrahost genetic heterogeneity. Hepatitis C virus (HCV) infection is an important public health problem worldwide.