Viral diseases are diseases that are caused due to virus namely AIDS, Ebola, Influenza, SARS (Severe Acute Respiratory Syndrome), Chikungunya, Small Pox, etc.

Transmission of the virus through the biting of infected animals, birds, and insects to humans is known as Zoonoses. Examples: Rabies virus. Alphavirus, Flavivirus, Ebola virus, etc.

There are four different types of viruses based on the type of host namely Animal viruses, Plant viruses, Bacteriophage and Insect virus.

An example of the replication of the virus within the cytoplasm in the host cell is all RNA virus except the influenza virus.

Viruses do not contain ribosomes, so they cannot make proteins. That is why they are dependent on their host. Viruses have different shapes, sizes and can be categorised by their shapes.

Some viruses cover themselves with a modified section of the cell membrane by creating a protective lipid envelope example the influenza virus and HIV.

Viruses can spread through touch, exchanges of saliva, coughing or sneezing, contaminated food or water and also through insects that carry them from one person to another.

Virus replicates in the body and starts to affect the host after a period known as the incubation period and symptoms may start to show.

Double-stranded DNA is found in poxviruses, the bacteriophages T2, T4, T6, T3, T7, Lamda, herpes viruses, adenoviruses, etc.

A virus that is made up of a DNA or RNA genome inside a protein shell is known as a capsid. Some viruses have an external membrane envelope.