Viruses are submicroscopic infectious agents. They replicate only inside the living cells of organisms. All living things are infected by viruses. These include bacteria, plants, and animals. Among all these species, archea and bacteria are the most common. There are many different kinds of viruses. Listed below are the most common ones: influenza, AIDS, and HIV. There are also some unusual viruses. Here is a list of the most interesting ones.


Viruses cause disease when they infect cells, so they are not pathogenic. Humans and animals can contract a number of diseases due to viruses. However, some of these infections can be harmless and even asymptomatic. They affect various systems of the body, including the liver and brain. In addition, viruses have been linked to several cancers. While they are not able to reproduce on their own, they can be transmitted from one person to another.

Viruses are divided into several types. These include the enterobacteriophages, bacteriophages, and adenovirus. The bacteriophages, which are microscopic and have a complex outer wall, inject their DNA and genome into the host cell. Then, the virus infects the host cell and sends progeny viral particles into the body. These progeny viruses can be either stored within the host cell or extruded repeatedly. This is known as the viral infection cycle. The lytic cycle causes death, while the lysogenic cycle allows the viral particle to remain in the host cell.

The virus replication process begins when the virus infects a host cell. The viral particle penetrates the host cell membrane and uncoated from its protein envelope. Then, the virus hijacks the host cell’s machinery and carries out replication. The host cell produces proteins to make new capsids. After these viral particles are made, they are assembled into new viruses and released into the environment. Most of these viruses also take part in the host cell’s membrane during the lysis.

A virus can be either a bacterial or a plant virus. The viral infection cycle is a continuous cycle that takes place over time. Some viruses live on host cells for a long time, while others will remain only for a very short period of time. The lytic cycle is the most dangerous because it may result in the death of the host cell. It is important to distinguish between a lysogenic and lytic viral infection.

Viruses have many names. A virus can be classified into two major families: Orthomyxoviridae and Togaviridae. The first two describe its nature, while the latter describes the nature of its disease. RNA is the most common type of virus in humans, and the second is the most common one in animals. The last is a parasite. It can live on the inside of the host. Its genome is a large molecule that is composed of RNA and DNA.