# Virology Test Note --- # Herpesviruses MD=markdown [Herpesviruses](https://www.ncbi.nlm.nih.gov/books/NBK8157/) are in [Herpesviridae](https://en.wikipedia.org/wiki/Herpesviridae) family. --- Virion shape is like this:  --- > Herpesviruses are known for their ability to establish lifelong infections. One way this is possible is through immune evasion. Herpesviruses have many different ways of evading the immune system source: [Wikipedia](https://en.wikipedia.org/wiki/Herpesviridae#Immune_system_evasions) --- Here's a video about Herpesvirus replication cycle: {%youtube fH1zS7hlW54%} --- # Coronavirus > [time=Thu, May 13, 2021 2:56 PM] > The name "coronavirus" is derived from Latin corona, meaning "crown" or "wreath". Source: [Ethymology](https://en.wikipedia.org/wiki/Coronavirus#Etymology) --- It looks like:  Source: [PHIL](https://phil.cdc.gov/) --- **SARS-CoV-2 transmission**  Source: [The Natural History](https://link.springer.com/article/10.1007/s11481-020-09944-5) --- **SARS-CoV-2 life cycle in virus susceptible host cells.**  Source: [The Natural History](https://link.springer.com/article/10.1007/s11481-020-09944-5) # Retrovirus > A retrovirus is a type of virus that inserts a copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. Source: [Wikipedia](https://en.wikipedia.org/wiki/Retrovirus) --- Virion shape is as follows:  --- Lifecycle of the Retrovirus:  --- # Picornavirus > Picornaviruses are a group of related nonenveloped RNA viruses which infect vertebrates including mammals and birds. They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30 nm icosahedral capsid. Source: [Wikipedia](https://en.wikipedia.org/wiki/Picornavirus) --- Virion shape is as follows: ![](https://upload.wikimedia.org/wikipedia/commons/e/ef/Rhinovirus.PNG width="200" height="200") <img src="https://upload.wikimedia.org/wikipedia/commons/e/ef/Rhinovirus.PNG" width="300" height="300" />    --- # ELISA  --- Figure 1.2 Serological techniques in virology. The four assays illustrated in this figure have been used for many years and are of widespread value in many circumstances. They are used to test both for viruses and for immune responses against virus infection. (a) The complement fixation test works because complement is bound by antigeneantibody complexes. Sensitized (antibody-coated) red blood cells, known amounts of complement, a virus antigen, and the serum to be tested are all added to the wells of a multiwell plate. In the absence of antibodies to the virus antigen, free complement is present, which causes lysis of the sensitized red blood cells (hemolysis). If the test serum contains a sufficiently high titre of antivirus antibodies, then no free complement remains and hemolysis does not occur. Titrating the test serum through serial dilutions allows a quantitative measurement of the amount of antivirus antibody present to be made. (*source*: Principles of Molecular Virology, 5th Ed. p.12)