Human herpes virus 8 - also known as carposome sarcoma herpes virus - is a double-stranded DNA virus.
In the large family of herpes viruses, it belongs to the subgroup of gammaherpesviruses.
The herpes viruses belong to a generally very well-known family of viruses that can cause various popular diseases such as the fever blister, chicken pox (caused by the varicella virus) or shingles (when the varicella virus reactivates).
The virologists Patrick S. Moore and Yuan Chang, together with their research group, were able to identify the virus in 1994.
They had noticed the frequent occurrence of Kaposi's syndrome in people with HIV and were able to classify herpesvirus 8 (HHV-8) on closer examination.
Like all other herpes viruses, human herpes virus 8 has a very long latency. It can exist in the body for years without being noticed, but can reactivate and appear at any time.
Transmission of human herpes virus 8
Human herpes virus 8 is transmitted via saliva and other bodily secretions.
It can therefore be transmitted not only during sexual intercourse, or direct contact with contaminated blood, but also through kissing or other direct exchange of bodily fluids, such as passing on pre-chewed food. In our latitudes, this practice is rather unknown and not carried out, but among indigenous people it is still a common method of feeding infants.
However, in case of infection, this way of feeding can lead to the virus being passed on.
Especially in regions where HIV infection affects a very high percentage of the population, this can become an extremely dangerous problem, as very often children are already affected by the immunocompromising disease.
What diseases does the human herpes virus 8 cause?
Three diseases have been found to be caused by human herpesvirus 8. It has been found that infection with human herpesvirus 8 is directly related to the development of Kaposi's sarcoma, lymphomas in so-called serous body cavities and some types of Castelman's disease.
Kaposi's sarcoma
Kaposi's sarcoma was first described in 1872 by Moritz Kaposi, an Austrian dermatologist (from Hungary). He defined it as idiopathic multiple pigment sarcoma.
The disease involves blue-brownish tumour nodules that appear on the skin, on mucous membranes and in the intestines.
Older and immunocompromised persons are affected. Since it appeared more frequently in HIV-positive people at the onset of AIDS, it was mentioned as a symptom in the first definition of AIDS (1981).
If one is infected with the Kapos sarcoma herpes virus, there are no restrictions if the immune system is healthy.
It is only when the immune system is weakened and can no longer fight off the virus sufficiently that it multiplies unchecked, which can lead to Kaposi's sarcoma.
Reasons for the weakened immune system could be severe previous illness, therapies with immunosuppressants (e.g. after organ transplants), ageing or the onset of AIDS.
The disease appears with livid patches and nodules on the skin. The main areas affected are usually the feet, legs, trunk and face. The edge of the lesion is not clearly demarcated, but is indistinct and irregular and does not cause pain. Lymph nodes may also be affected, leading to the formation of lymphoedema. If the disease spreads throughout the body as it progresses, the mouth, genitals and internal organs may also be affected. If the internal organs are affected, there is a risk of bleeding, leading to haemoptysis and vomiting of blood.
Lymphomas in serous body cavities
Serous body cavities are those crevices in the body that are lined by the so-called tunica serosa.
This lining allows the crevices to move in relation to each other. Serous body cavities are the pleural cavity, the pericardial cavity, the peritoneal cavity and the scrotal cavity. If a lymphoma forms in one of these areas, it is called primary effusion lymphoma (PEL).
Castelman's disease
Castelman's disease is also a tumour that affects the lymph nodes. The disease is also called angiofollicular lymph node hyperplasia or giant lymph node hyperplasia.
The disease is divided into three different forms, the form that is linked to infection with human herpes virus 8 is called HHV8-associated multicentric form.
The other two forms are the idiopathic multicentric form (iMCD) and the unicentric form (UCD).
If you develop the multicentric form of Castelman's disease, there is an increased release of interleukin 6, which causes the following symptoms: Weight loss, fever, swelling of the lymph nodes, enlargement of the spleen, enlargement of the liver, hypoalbuminemia, hypergammaglobulinemia, fatigue.
In particular, HIV patients who have been infected with human herpes virus 8 have an increased risk of contracting Castelman's disease.
The human herpes virus attaches itself to the B cells, causing them to begin to proliferate as large plasmablasts.
Why does human herpes virus 8 belong to the oncoviruses?
Three cancerous diseases could be manifested whose development can be directly traced back to human herpes virus 8.
Uncontrolled multiplication of the virus leads to abnormal cell growth. In immunocompromised individuals, the virus does not cause any symptoms. However, due to viral latency, the virus remains in the body for life. Therefore, it can cause problems if one suffers an immunocompromising disease. The virus can become active in cells, and cancer can develop.
How can I protect myself?
Vaccination against the virus is not currently possible.
Since it is transmitted via body fluids, you can protect yourself by avoiding direct contact with the body fluids of an infected person.
This means no unprotected sex, no exchange of saliva and no use of used syringes.
Unlike other viruses, the virus is not very widespread. It is completely harmless for immunocompromised persons.
If you have a known immunocompromising disease, it is important to protect yourself from infection, as human herpes virus 8 can be responsible for cancer in this case.
Treatment of human herpesvirus 8
No treatment is needed for immunocompromised people, as the active virus does not cause any symptoms and there are no problems even when it is inactive. If the virus occurs in immunocompromised persons, antiviral drugs are administered for treatment.