Classification
Herpes simplex is divided into two types: HSV type 1 and HSV type 2. HSV1 causes primarily mouth, throat, face, eye, and central nervous system infections, whereas HSV2 causes primarily anogenital infections. However, each may cause infections in all areas.[3]
Signs and symptoms
HSV infection causes several distinct medical disorders. Common infection of the skin or mucosa may affect the face and mouth (orofacial herpes), genitalia (genital herpes), or hands (herpetic whitlow). More serious disorders occur when the virus infects and damages the eye (herpes keratitis), or invades the central nervous system, damaging the brain (herpes encephalitis). People with immature or suppressed immune systems, such as newborns, transplant recipients, or people with AIDS are prone to severe complications from HSV infections. HSV infection has also been associated with cognitive deficits of bipolar disorder,[4] and Alzheimer's disease, although this is often dependent on the genetics of the infected person.
In all cases HSV is never removed from the body by the immune system. Following a primary infection, the virus enters the nerves at the site of primary infection, migrates to the cell body of the neuron, and becomes latent in the ganglion.[5] As a result of primary infection, the body produces antibodies to the particular type of HSV involved, preventing a subsequent infection of that type at a different site. In HSV-1 infected individuals, seroconversion after an oral infection will prevent additional HSV-1 infections such as whitlow, genital herpes, and herpes of the eye. Prior HSV-1 seroconversion seems to reduce the symptoms of a later HSV-2 infection, although HSV-2 can still be contracted.
Many people infected with HSV-2 display no physical symptoms—individuals with no symptoms are described as asymptomatic or as having subclinical herpes.[6]
