Pathogenic Viruses

Over the course of human civilization, viral infections have caused millions of human casualties worldwide, driving the development of antiviral drugs in a pressing need [1, 2].

As of April 2016, antiviral drugs have been approved to treat 9 human infectious diseases:  HIV infections, hepatitis B (HBV), hepatitis C (HCV), human cytomegalovirus (HCMV), herpes simplex virus (HSV), human papillomavirus (HPV), respiratory syncytial virus (RSV), varicella-zoster virus (VZV), and influenza virus, albeit a definitive cure for most of them is yet to be discovered [3, 4]. Furthermore, there is still no antiviral drug or vaccine for over 200 human viruses afflicting populations worldwide [3].

The development of antiviral treatments remains a challenge due to the highly variable nature of virus genomes. Furthermore, the emerging drug resistance mutations remain a major cause of treatment failure, calling for a joint effort between scientific and industrial partners [4-8].

Viruses and cancer

Viruses account for ca. 20% of total human cancer cases. Although many viruses can cause tumors in animals, only seven of them are associated with human cancers and are considered oncogenic viruses: hepatitis B virus (HBV), hepatitis C virus (HCV), human papillomavirus (HPV), Epstein Barr virus (EBV), human herpes virus 8 (HHV8), Merkel cell polyomavirus (MCPyV), and the human T-lymphotropic virus (HTLV-1). Both HBV and HCV cause around 80% of hepatocellular carcinoma (HCC), the most common cancer of the liver. High-risk HPV strains are the major causes of cervical cancer and other ano-genital neoplasms, head and neck tumors. EBV is associated with nasopharyngeal carcinoma, Hodgkin’s lymphoma, and Burkitt’s lymphoma. HHV8 (also called Kaposi’s sarcoma-associated herpesvirus, KSHV) is responsible for Kaposi’s sarcoma, often found in patients with immunodeficiency syndrome (AIDS). MCPyV causes Merkel cell carcinoma and HTLV-1 is the causative agent of adult T-cell lymphoma [9].

Recently, Herpes virus 6A (HHV-6A) and 7 (HHV-7) has been linked to Alzheimer’s disease [10].

Antiviral compounds with broad-spectrum activity against different virus genotypes or subtypes are in demand, because the effectiveness of most antiviral drugs is limited to only certain viral strains [8].


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