Japanese hemagglutinating mouse virus - see Sendai virus
**Viruses** are intracellular parasites of animals and humans. More than 500 viruses are known to cause various diseases in humans, but only about 20 are of broad medical significance. About 40 thousand infectious diseases are caused by viruses; Among them, 5-6 thousand have a chronic course. Less than 1% of infectious diseases do not have a viral etiology. Recovery from viral infections is usually possible without any consequences.
Virology – the science of viruses: 1. localization of the virus in the cell; 2. methods of penetration; 3. transfer and ability for further reproduction in young cells; 5. actions of the virus. The classification is presented according to the method of virus penetration through the membrane of host cells (depending on the surface of the eukaryotic cell): viruses with a lytic mechanism of action (destructive) and viruses with an alethic mechanism of action. Most viruses have lytic mechanisms. Phagotonic and picornal viruses are viruses with an alytic route of entry.