Importance of viral genetic variability in human diseases

Pesistant viral infections represent great medical chalenge for diagnosis, monitoring and treatment. The life-long viral presence in chronic, latent or slow infections is associated with genetic variability of the virus with different mutation rates.The specific mutations at the characteristic positions infuence biological properties of the virus, by altering virulence and replicative ability, enabling escape from the host immune response or introducing resistance to antiviral therapy. Resistance to antivirals is the inevitable consequence of incomplete viral supression and selective pressure of the drug and its appearance is most prominent in immunocompromised patients on prolonged therapy. The other emerging problem is further circulation of resistans virus strains in the population. This study will include molecular analyses, genotypic and phenotypic characterization of viruses causing most important persistant infections (HBV, HCV, EBV, CMV, JCV, BKV, HPV and Parvovirus B19). Viral genetic characteristics will be correlated to virulence and other biological consequences of mutations particularly those important for diagnosis, prevention and treatment of persistant infections. The specific attention will be paid to oncogenic potential of EBV, HPV and hepatitis viruses. The results will contribute to the development of strategies for prevention of these diseases and optimal use of antiviral treatment.