Herpes simplex 1, or herpes simplex virus, type 1, HSV-1, is a highly contagious infectious agent that replicates itself within cells of a living host. It can infect animals other than humans, though only humans show symptoms of infection, according to the University of South Carolina, USC. Belonging to a family of viruses called herpesviridae, HSV-1 is spread from person to person in a number of ways, including self-inoculation and direct physical contact.
Herpes Family
There are at least 25 known strains of the virus in the herpesviridae family. Of these, eight are known to infect humans, including HSV-1. It targets mucoepithelial cells found in the skin and mucus membranes. USC reports that as long as the virus remains moist, it can cause an infection. It remains in the body for life and can cause recurrent outbreaks.
Latency
HSV-1 is highly pervasive. The University of Maryland Medical Center, UMMC, reports that by adulthood between 30 and 90 percent of all people will show antibodies to HSV-1. After a person is infected with HSV-1, in an event called the "primary infection," the virus goes dormant for a period of time. This period of inactivity, or latency, allows the virus to remain in the body without the immune system attacking it. For unknown reasons, the virus can become active again.
Oral Herpes
HSV-1 can be found in the saliva of an infected individual and is most often the cause of cold sores on or around the mouth. USC reports that the initial eruption can spread to all areas of the mouth and pharynx. It can be passed from individual to individual through kissing, which is often how it is passed to children, according to the American Social Health Association, ASHA, though it can also be transmitted through shared utensils, or via the hands of an infected person.
Genital Herpes
While another strain of herpes, herpes simplex virus, type 2, is the usual cause of genital herpes, HSV-1 can cause a genital infection. It can be transmitted through oral sex, or through genital to genital sex from an individual genitally infected with the virus.
Symptoms
The classic HSV-1 symptom is an itchy or painful blister, or cluster of blisters, that eventually crusts over and dries out, leaving no scars. A day or two before the eruption of the blisters, there is often a tingling or burning feeling in the area where the outbreak is going to occur. The outbreak usually lasts eight to 10 days, according to ASHA. Many people infected with herpes do not know they have the infection because herpes outbreaks can by asymptomatic.
