Herpesviridae is the name given to a family of viruses, eight of which are known to infect human beings. Other strains of herpes viruses can infect horses, cattle, cats, pigs, chickens, turtles, fish and even oysters, according to the Los Alamos National Laboratory, LANL. The strains that infect humans are endemic, meaning that once infected, a person harbors the virus forever. After the initial, or primary, infection, the virus enters a period of latency, or hibernation. At certain times, or under certain conditions, it can reawaken.
Herpes Simplex Virus, Type 1
Generally considered the type of herpes that causes cold sores around the mouth, Herpes Simplex Virus, Type 1, HSV-1, can also cause genital herpes outbreaks. The virus commonly spreads through kissing and infects the majority of people when they are children. The American Social Health Association, ASHA, reports that 50 to 80 percent of American adults have oral herpes. HSV-1 can cause facial, labial, ocular and genital lesions.
Herpes Simplex Virus, Type 2
Usually, the cause of genital herpes, Herpes Simplex Virus, Type 2, HSV-2, also causes a minimal number of oral outbreaks. After the primary infection, which does not always include symptoms, the virus most often retreats to the sacral ganglia, a hub of nerves located at the base of the spine, according to ASHA. It reactivates from time to time, usually as a result of stress and returns to the site of infection.
Varicella-Zoster Virus
The Varicella-Zoster Virus, VZV, causes chickenpox and, later, shingles. Chickenpox, a common childhood disease, causes a widespread body rash. After the primary infection, it is rare for chickenpox to reoccur. Rather, the virus hibernates in the nervous system. When it reactivates, it causes a similar disease, shingles, which is usually limited to a smaller outbreak on one side of the body, neck, face or scalp. Chronic pain is often a symptom of shingles, according to the University of Wisconsin-Madison, UWM.
Cytomegalovirus
Discovered in the 1950's, Cytomegalovirus, CMV, has the largest genome of herpes viruses and seems to only infect humans, according to UWM. Approximately 15 percent of the U.S. population is seropositive for CMV, with the percentage increasing to 50 percent by the age of 35. CMV is transmitted through sexual activity and kissing. It infects the upper respiratory tract first, before moving to the spleen and lymph nodes. Though usually asymptomatic, CMV can cause fever.
Human Herpes Virus 6
Affecting the majority of children by the age of 2, Human Herpes Virus 6 causes roseola, a rosy rash that may include a fever. Almost never fatal, HHV6 transfers through saliva and may have some association with multiple sclerosis, according to UWM.
Human Herpes Virus 7
Causing pityriasis rosea, a skin rash with mononucleosis-type symptoms, HHV7 was discovered in the 1980's. Like CMV and HHV6, HHV7 is lymphotropic, meaning that it is associated with the lymph nodes, according to the Multiple Sclerosis Encyclopedia, MSE.
Epstein-Barr Virus
Epstein-Barr Virus, EBV, discovered in the 1960's, causes infectious mononucleosis in the west, as well as two types of cancer found in the tropics, MSE reports. In Africa, EBV causes Burkitt's Lymphoma, a tumor on the jaw and face in young children. In south China, Alaska, Tunisia and East Africa, it causes nasopharyngeal cancer, a tumor in the upper respiratory tract, according to UWM.
Human Herpes Virus 8
Human Herpes Virus 8, or Kaposi's sarcoma-associated herpes, KSHV, is a co-factor in the development of Kaposi's sarcoma in immuno-compromised people, including those who have AIDS. Kaposi's sarcoma is a cancer that causes tumors to grow under the skin, according to Medline Plus.
