Viruses today and tomorrow.

The current studies show that viral infections can cause not only acute, but also persistent viral diseases. A certain number of viruses are able to incorporate their nucleic acid into the genome of the host-cell, leading to rearrangement of the cell genes and formation of malignant tumors. Viral persistence can cause manifestations of latent or chronic infections, as well as prion-caused slow infections of the central nervous system. Defective Di particles play an important role in maintaining viral persistence. Viruses are important agents involved in various disorders of the immunological homeostasis of the organism.