Overview of the Nine Types of Herpes Viruses Found in Humans
1. Herpes simplex virus Type 1 (HSV-1)
Fever blisters and cold sores of the face, mouth, and lips are the most common symptoms of HSV-1 outbreaks. Also known as Human Herpes Virus-1 (HHV-1).
Surprisingly, most infections with this virus occur by two years of age via breaks in the skin barrier around the mouth or elsewhere on the body. While HSV-1 is thought of as the cold sore virus and HSV-2 (see below) is thought of as the genital herpes virus, distinctions between them often fail. It is well documented in the medical literature, although not yet widely publicized, that the virus released from a cold sore can easily transfer via oral-genital contact to establish a genital herpes infection in another individual.
Besides causing cold sores and possibly spreading to the genital region, HSV-1 has also been linked with the development of serious neurological diseases such as Alzheimer’s disease, Bell’s palsy and trigeminal neuralgia. Recent research also shows that co-infection by HSV-1 and HIV (human immunodeficiency virus) can enhance the activity of both viruses in patients who have AIDS and non-genital herpes lesions.
HSV-1 infects at least 50% of people worldwide.
2. Herpes simplex virus Type 2 (HSV-2)
Also called Human Herpes Virus-2 (HHV-2). This type is the usual cause of genital herpes, which is classified as a sexually transmitted disease. HSV-2 reached epidemic status in the 1980s and 1990s, mostly because of its increased incidence among teenagers. In the world of virus classification, HSV-2 and HSV-1 are nearly indistinguishable except for their different clinical symptoms. However, even these differences are inconsistent, since both types of herpes simplex can cause oral and genital herpes outbreaks.
3. Herpes zoster virus (HZV)
Also called Varicella zoster virus (VZV) and Human Herpes Virus-3 (HHV-3). Chickenpox results from a first time infection by HZV. When this virus recurs later in a person’s life, it causes shingles. As the average age of our population increases, more and more people are suffering recurring bouts of post herpetic neuralgia (nerve pain) as a result of shingles. This herpes virus is considered to be the most infectious of the known herpes viruses. Greater than 90% of the population is infected.
HZV has been linked to the autoimmune disease called lupus. Furthermore, HZV outbreaks, which are now epidemic among people with AIDS, are often the earliest indicator of HIV infection.
4. Epstein-Barr virus (EBV)
Also called Human Herpes Virus-4 (HHV-4). The major cause of infectious mononucleosis (“kissing disease”), EBV may also be the leading culprit in causing Chronic Fatigue Syndrome and other disorders of the immune system. EBV has also been linked with lupus, lymphomas, and other cancers. This virus is now considered to be quite damaging and mutagenic (causes genetic mutations) in the body.
Around 75% of the population will test positive for EBV.
5. Cytomegalovirus (CMV)
Also called Human Herpes Virus-5 (HHV-5). CMV can cause mononucleosis and hepatitis and it can also be sexually transmitted. Recent research suggests that CMV has a role, in conjunction with other types of viruses, in turning on cancer genes.
The occurrence of CMV is strongly correlated with vascular diseases such as coronary artery disease and atherosclerosis. Even though it is generally asymptomatic, CMV may turn out to be a key factor in the development and progression of heart and blood vessel disease, one of the leading killers in all developed nations.
CMV infects about 60% of adults, but is even more common among homosexual men and is associated with AIDS.
6. Human Herpes Virus-6
7. Human Herpes Virus-7
8. Human Herpes Virus-8
9. Human Herpes Virus-9
(HHV-6, HHV-7, HHV-8, and HHV-9, respectively)
All HHVs are associated with disorders of the immune system, especially AIDS. HHV-8 is also called Kaposi’s sarcoma associated human herpes virus (KSHV), which causes a type of skin cancer that occurs most often in people with AIDS.
The recent discovery of new HHVs in people with AIDS suggests that there are more herpes viruses to be discovered. Indeed, new types of these herpes viruses are probably evolving every year. HHV-6 and HHV-7, both found in about 90% of the population, are two closely related viruses that are relatively new discoveries and are considered to be “universal” herpes viruses.
Infection with HHV-6 during childhood causes “roseola infantum,” a.k.a. “sixth disease.” HHV-6 has recently been linked with the development of multiple sclerosis.