Herpes simplex virus (HSV)

The Pathology Dictionary Team
April 13, 2023

What is herpes simplex virus?

Herpes simplex virus (HSV) is a DNA virus that belongs to the family Herpesviridae. There are two types of herpes simplex virus: HSV-1 and HSV-2.

What medical conditions are caused by herpes simplex virus?

The most common medical condition caused by HSV is called herpes. HSV-1 typically causes oral herpes, which is also known as cold sores or fever blisters. It can also cause genital herpes, but this is less common. HSV-2, on the other hand, usually causes genital herpes, but can also cause oral herpes.

How do you get herpes simplex virus?

Both HSV-1 and HSV-2 are highly contagious and can be spread through direct contact with the sores or blisters that are present during an outbreak. HSV can also be spread even when there are no visible sores present, as the virus can be shed from the skin or mucous membranes without causing any symptoms.

What do cells infected with herpes simplex virus look like under the microscope?

When viewed under a microscope, cells infected with HSV may show a variety of features depending on the stage of infection. In the early stages of infection, the cells may appear swollen or rounded, with changes in the cell surface and loss of connection to neighboring cells. As the infection progresses, the cells may show evidence of viral replication, with the formation of characteristic inclusion bodies, which are clusters of viral particles that can be seen within the nucleus of the infected cell. Pathologists often describe these changes as viral cytopathic effects. Later stages of infection can lead to cell death, with the release of new virus particles that can go on to infect neighboring cells. A test called immunohistochemistry is often used to confirm the presence of HSV inside infected cells.