First, the virus has to be able to invade the new host’s cells: That’s a minimum requirement for making the host sick. But to become capable of causing epidemics, the virus also has to become infectious — that is, transmissible between individuals — in its new host.Why are some viruses difficult to treat?
However, some viruses are not successfully treated by the immune system, such as human immunodeficiency virus, or HIV. This leads to a more chronic infection that is difficult or impossible to cure; often only the symptoms can be treated.What is the Assembly and release of viruses?
Assembly – viruses are produced from the viral components. Release – newly formed virions are released from the cell. Outside of their host cell, viruses are inert or metabolically inactive.What is the scariest virus in history?
Many of the scariest viruses that have caused past or current epidemics originated in other animals and then jumped to people: HIV from other primates, influenza from birds and pigs, and Ebola probably from bats.