There are two main types of herpes simplex virus (HSV). Type 1 mainly causes cold sores and type 2 mainly causes genital herpes.
HSV1 can also trigger genital infections and, conversely, viruses of type 2 can cause cold sores. The structures of the two pathogen types differ only slightly from each other.
The viruses of the herpes group – which also includes the varicella virus – are characterised by the fact that they settle in the nerve nodes after an initial infection and can survive there.
If the immune system is weak or in stress situations, reactivation of the infection is possible, so that blisters can occur again on the lips, in the mouth or genital area. Herpes simplex viruses are less likely to spread throughout the body (viremia), which is why transmission to the unborn child is very rare.
How widespread are the herpes viruses?
Infection with type 1 herpes viruses usually occurs in childhood. Depending on their socio-economic status, 70 to 90 percent of the adult population are infected with HSV1. With the onset of sexual contact, an increase in HSV2 infections can be observed. Adult transmission varies between 20 and 80 percent, depending on sexual activity and the number of sexual partners.
HSV1 is mainly spread by droplet infection. In HSV2, secretions of the genital tract play a decisive role.
Children of virus-excavators – regardless of whether the mother shows symptoms of the infection or not – become infected in most cases during the passage of the birth canal. Transmission is also possible in close contact after birth. The virus is very rarely transmitted to the child via blood vessels and placenta.
What are the symptoms?
Initial infections with herpes viruses often go unnoticed. In the HSV1 type, cold sores may occur and may also spread into the oral cavity. At first, blisters form which burst open after a certain time. As a result, small, subjectively mostly very unpleasant ulcers can be noticed.
In type 2 infections, painful small vesicles form on the genitals and are arranged in groups. After bursting, ulcers develop which heal without scarring. In some cases, fever, lymph node swelling, urination pain, headache and muscle pain may also occur.
Complications occur especially in people with a weakened immune system. After an initial infection, the viruses can be detected in the affected area for a longer period of time than after a reactivated infection.
When do new infections occur?
Both types of herpes can be reactivated, i.e. they can reappear after some time. The reason for this is a disorder of special immune defence mechanisms. With increasing age, however, a recurrence occurs less frequently. Reactivated infections can also occur without symptoms. In these cases there is a particularly high risk that the virus will spread unnoticed.
The following factors favour a recurrence of the infection
- UV radiation / sunbathing
- Taking drugs to weaken the immune response (immunosuppression)
- Hormonal change during menstruation or pregnancy
Complicated processes occur above all after reactivations.
The following symptoms may occur:
How can the infection be prevented?
In principle, the risk of infection can be significantly reduced with safer sex measures.
Passive prophylaxis with immunoglobulins and aciclovir therapy is recommended for newborns whose mothers have undergone a symptomatic or asymptomatic initial infection shortly before delivery. Eye drops should be administered after birth.
If the initial infection with the mother’s lip or genital herpes occurs around the birth date, mother and child should be isolated from other women in childbed until the vesicles heal. If a reactivated infection occurs, careful hygienic measures are sufficient. Isolation is not necessary in this case.
A vaccination against herpes infections does not yet exist.
Stay informed with the newsletter of netdoktor.at
Authors: Dr. Britta Bürger (2002) , Mag. (FH) Silvia Hecher, MSc Editorial work: Dr. med. Matthias Thalhammer
Status of medical information: September 2010
Guidelines for the therapy of classical venereal diseases and Sexually Transmitted Infections. Working group for STD and dermatological microbiology of the Austrian Society for Dermatology and Venerology. November 2009.
Buxbaum S et al: Epidemiology of herpes simplex virus types 1 and 2 in Germany: what has changed? Med Microbiol Immunol. 2003 Aug;192(3):177-81. Epub 2003 May 22.
Jung E, minor I: Dermatology. Thieme Verlag, 2005. Goerke K, Valet A, Bock K: Gynaecology and obstetrics. Elsevier Publishers, 2006.
More articles about this topic
Herpes during pregnancy
Genital herpes is the second most common sexually transmitted disease. It is also important during pregnancy to prevent this …